Albert Einstein also predicted the existence of something called gravitational waves. He did this in his theory of general relativity in 1916, and the study still continues today.


What is a gravitational wave? Gravitational waves are ripples in the curvature of space-time itself, which propagate as waves away from the source of gravity. These sources are large bodies of mass, like a neutron star or a black hole.


We have seen indirect evidence of gravitational waves, but we still have not directly observed gravitational waves. In March 2014 however, an image produced by the Harvard-Smithsonian Center for Astrophysics appears to show evidence of the waves existence around the time of the big bang! Some further analysis is required before this conclusion can be made however.




Gravitational waves can be very useful in astrophysics. They can be used to make observations and measurements of very large objects, like black holes. The nice thing about gravitational waves is they appear to be unaltered by matter in the path of propagation. This means there is much less noise in detected signals, compared to traditional methods of measurement.


Click here for a printable version of this page.


There are 18 scientific principles, most of which kids need to know before they hit college. With the content in this unit, you’ll be able to quickly figure out what they know and where the gaps are, so you can focus on the areas you need to most.


Once kids have wrapped their heads around these ideas, they can pretty much explain the universe around them, including why airplanes fly, how electricity works, and why socks disappear in the dryer.


Don’t worry if these ideas are new to you – it may have been that no one has ever explained them to you or how important they are. The content in this unit is just a quick overview of what we’ll be learning in the main e-Science Online Learning program. The content in this program can be stretched over several years, so don’t try to cover it all in one night.


You’ll be able to tell when your child has mastered these principles in the way they describe how things work when they teach these ideas to others.


One of the most important things you can do as parents is to focus on the long-term outcome (how to think like a scientist), not how quickly you can get your child to memorize these top principles.


Scientists do real science by being patient observers, getting curious about the world around them, and asking questions.


There seems to be a predominant myth about scientists: that real scientists put on a white lab coat, walk into their lab, and have an ah-HA! moment about how to cure the common flu or invent warp drive and then fame and fortune follows (along with a wild hairdo).


That’s not the way real scientists do science. In fact, nothing could be further from reality.


Real scientists are everyday folks that have a curiosity mindset (How does that work? Why did that happen? What’s really going on here?) and are really good at watching the world around them. They see things in ways most people overlook. Why are things overlooked? Either because they are too busy or just weren’t trained to think like a scientist.


Thinking like a scientist is a way you train your mind to focus on how you can make things better for people or the planet. It’s a way of contributing while at the same time challenging yourself to understand something that you didn’t just a moment ago. It’s fun to figure things out if they are not too far out of reach. Just as you wouldn’t teach a toddler to sky-dive, we wouldn’t start you on your science adventure with stuff that too complicated to understand. We’ll make sure to go at your pace and throw enough solid content your way so you grow in order to keep up.


One of the quickest ways to kill your child’s passion for science is to not teach him how to deal with frustration when it pops up. If you’re anxious about doing science because you don’t want him to ever feel frustrated while doing science, let me tell you the good news up front:


SCIENCE CAN BE FRUSTRATING! This is especially true if you’re doing an experiment right in front of other people.


While every scientist gets to feeling frustrated or disappointed at times, they also don’t stay there long. When an experiment goes awry, or something doesn’t work, it’s important to work through these emotions (and events) with your child so they get into the habit of picking themselves up, brushing themselves off, and getting back in the saddle. What this usually means is taking a closer look at your experiment setup, your original ideas and guesses and see what happened.


Everyone gets frustrated. It’s part of life, part of reality. What’s not realistic is letting frustration stop you, or even reliving the same frustration over and over in your mind. That’s not how the real world operates. Everyone experiences setbacks, and the sooner your child figures out how to deal with these, the more resilient they are going to be and the faster they’re going to learn what works and what doesn’t.


In fact, one of the greatest experiments of all time gave a null result, which baffled top scientists for decades until Einstein came to the rescue with his special theory of relativity. It was the 1887 Michelson-Morley experiment that failed to detect the Earth’s motion through the ‘ether’. It’s good thing, too, because now we know the truth Einstein’s relativity principles that tell us the speed of light being constant for all observers (we’ll cover more of that in Unit 7).


We’re going to focus on the top scientific principles that will make you a brainiac extraordinaire. You might be surprised at the materials or experiment setup. But real science doesn’t need to be fancy – you can demonstrate all of these spades of science for dirt cheap. Ready?


Newtonian Physics

Scientists study motion. They study how things move through space and time in order to understand and predict the world.


The Principles of Galilean (Newtonian) Relativity are where Einstein’s original principles of relativity came from. The ideas that “I am at rest” don’t mean anything unless you talk about your motion relative to something else.


There is a natural state of motion to move at constant speed in a straight line. When you toss a ball, it wants to go in a straight line. But air resistance (drag) and gravity are working to bring it to a stop. Launch a Voyager spacecraft into space and it goes in a straight line until it hits something or is gravitationally affected by another object.


Newton’s three laws of motion (which are based on Galileo’s work) make all motion predictable once we know all the forces acting on the object:
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First Law: Objects at rest stay at rest. Objects move uniformly unless acted on by outside forces. The soccer ball rolls down the field because you pushed it (or kicked it), and it rolls to a stop because of air resistance (the ball hits air particles) and friction (between the ground and the ball). More on this in Unit 1 and Unit 2.


Second Law: F=ma. This tells us how much force makes a change in motion. Acceleration (a) is the change of velocity. Velocity has two parts: speed and direction (55 mph heading east is velocity.)


When you hit the gas pedal (accelerator) in the car, the car changes speed (accelerates). When you make a turn while traveling at constant speed, you are also changing the velocity (changing the direction), so traveling in a circle is also acceleration.


This law also states that momentum is always conserved. That is, mass multiplied by velocity into a system equals the mass multiplied by the velocity coming out. For example…


When you aim a billiard ball toward another, the momentum  is transferred from one ball to another. The first ball will slow if not stop altogether after impact while the second one zooms away. More on this in Unit 1 and Unit 2.


Third Law: For every action there is an equal and opposite reaction. Another way of saying this is that forces come in pairs. If you push against the wall, the wall pushes back against you with the same about of push (force). A rocket fires a flame out the back which pushes it forward. More on this in Unit 1 and Unit 2.


Law of Gravitation: Every object attracts another with a force that depends on both their masses and the distance between them.


Newton realized that the circular motion of the planets and the apple falling from the tree are really the same thing. (Whether he was hit on the head with the apple first is still up for debate.)


Further, he guessed that all objects have an attraction to each other.


He was on his way to prove this idea when he ran into a road block – the math he needed to prove his idea about gravitation did not yet exist. So he invented a branch of Mathematics (called Calculus) in order to figure out his law of gravitation. More on this in Unit 1.


Maxwell’s Equations

James Maxwell and a host of others worked to form new ideas that formed a new branch of physics called Electricity & Magnetism.


Maxwell’s First Equation: Electrical charge is a fundamental property of matter. Like charges repel, and opposite charges attract. A balloon rubbed on your hair collects a negative static charge as electrons are collected on the balloon. These negative charges attract the positive charges in your hair and your hair stands up when the balloon is brought close. More on this in Unit 10.


Maxwell’s Second Equation: All magnets have two poles. Like poles repel, opposite poles attract. North attracts the South pole of a bar magnet. More on this in Unit 11.


Maxwell’s Third Equation: Invisible fields exert forces on charges and magnets. You can have an electric field or a magnetic field (or both).


Drop a magnet into a pile of iron filings, and you’ll find the filing arrange themselves to show you the magnetic field lines around the magnet.


You detect an electric field when you have a bad hair day! But here’s another way:


Place an object that is sensitive to electrical charges (like a fluorescent light) in an electrical field (you can do this by vigorously rubbing the outside of a long fluorescent light with a plastic bag), and you’ll find the fluorescent tube lights up without having it being plugged in! More on this in Unit 10 and Unit 11.


Maxwell’s Fourth Equation: A moving electric charge produces magnetism.


When you wrap a wire around a nail and run electric current through the wire, the nail-coil turns into a magnet (you can even pick up paper clips!). It’s called an electromagnet, as you can turn the magnet on and off by switching the electricity on and off.


Changing magnetic fields produce electric fields. Wave a permanent magnet back and forth along a coil of wire (or your electromagnet nail used previously), and you’ll measure a pulse of electricity.


Electromagnetic Radiation was first predicted by James Maxwell. He suggested when the magnetic fields produce electrical fields, those emerging electrical fields generated magnetic fields, which then created electrical fields… and continue to create each other, leap-frogging their way through space. He calculated the speed those waves would travel at and was surprised to find it was the speed of light! Maxwell concluded that light must be an electromagnetic wave traveling at speed c, which created a new field of study called optical science, now a branch of electromagnetism.


We’ll cover more on magnetism in Unit 11, and how to make circuits in Unit 10 and Unit 14.


The Electromagnetic Spectrum

If a wave moves across the surface of a pond, wave itself moves, not the water. The energy travels through water as a wave, just like light. Light waves are traveling energy, but they don’t need substances to travel through – they can travel through the vacuum of space.



If you could count the number of waves that pass by you in one second, the number would determine what color of light you see. Red light has 430 trillion waves that pass by in one second, while violet light has 750 trillion. The more energy a light wave has, the higher the frequency. Violet light is higher energy than red light.


Light travels at different speeds, depends on what it travels through. When light passes through different substances, the speed of the wave and the angle change, which is exactly what eyeglasses to: they allow you to focus the light.


The photoelectric effect (electrons are ejected from a substance when illuminated by an intense blue or UV light) was the first experiment that proved light traveled as a wave and interacted as a particle. When the light hits the substance, the photons (light particle) are absorbed and transfer their energy to the material, and if there’s enough energy, the electrons are allowed to escape. Hertz first saw this as sparks in his electroscope in the 1890s. We’ll cover more on this in Units 9 and Unit 10.


Ideal Gas Law

We live in a sea of air called the atmosphere. Everything around us has atoms pushing on it equally in all directions, a lot like a room full of continuously-bouncing ping pong balls.


Think of each ping pong ball as a molecule. If we raise the temperature of the molecules, they start whizzing around faster and faster.  Temperature is basically a speedometer for molecules. The faster they are wiggling and jiggling, the higher the temperature and the higher the thermal energy that object has.


If we lower the temperature, the ping pong balls move more slowly. The push the wall feels from each ball add up to equal the total pressure on the wall by the balls. The faster the balls move around, the more pushes the wall feels. This means the higher the temperature, the higher the pressure.


If we keep the temperature constant but instead shrink the size of the room in half, the balls also move more quickly. When the volume of a gas decreases, the temperature and pressure increase. More on this in Unit 13.


The Atom

All matter is made of atoms. An atom is the smallest part of stable matter.


If you magnify an apple to be the size of the earth, the atoms inside would be the size of an apple.


If you magnified the atom to be the size of the earth, then nucleus would be the size of a basketball at the center of the earth and the first electron shell would be on the surface of the earth. An atom is mostly empty space!


Atoms rarely hang out alone. They join together in groups from two to millions of atoms. H2O for example is made up of two hydrogen atoms and one oxygen atom.


Atoms are made of three basic particles: neutrons, protons, and electrons. Neutrons and protons are made up of smaller particles called quarks (more on this in Unit 7).


Neutrons and protons are together in the middle of the atom and make up the nucleus of the atom. Electrons move around the nucleus. They don’t “orbit” the nucleus. Next lesson we will talk more about how they move. It’s one of the wacky things about electrons.


Atoms differ from one another by how many protons, neutrons, and electrons they have in them.


Elements are specific kinds of atoms. Every atom is a type of element.


There are over 112 elements. Ninety of which are found naturally. Twelve different elements are the major ingredients of over 90% of all matter.


Five different elements are the major ingredients of all living things. Carbon, Hydrogen, Oxygen, Nitrogen, and Calcium are the five main elements that make up all living matter.


Most atoms come from stars and have been around since the beginning of time.


Atoms get used, and reused again and again as things change over time. Atoms, which is to say matter, cannot be created or destroyed, only changed into another form.


You can split apart the water molecule into separate tubes of hydrogen and oxygen using a battery. You can then recombine the hydrogen and oxygen back into water and use the energy generated by this combination to power a motor.  It takes energy to split apart the molecules, and the chemical reaction of recombining the atoms into a new molecule generated energy. Matter and energy are two sides of the same coin (more on this soon when we get to E=mc2).


Electrons are as small as you can get (only recently have scientists figured out how to split an electron… normally we call particles we can’t split apart any further ‘elementary particles’). Electrons don’t orbit nuclei. They pop in and pop out of existence. Electrons do tend to stay at a certain distance from a nucleus. This area that the electron tends to stay in is called a shell.


The electrons move so fast around the shell that the shell forms a balloon like ball around the nucleus.


An atom can have as many as seven shells. The number of electrons an atom has determines how many shells it has. A shell can only hold so many electrons. Atoms are “satisfied” if they have a full outer shell or if they have a multiple of eight electrons in their outer shell. If an atom is not “satisfied” it will gladly share electrons with other atoms forming molecules. We’ll cover more on this in Unit 3 and Unit 8.


States of Matter

There are five states of matter: Solid, liquid, gas, plasma, and BEC. Since BEC is only found at very unusual places in special laboratories, we’ll outline the four more common states of matter.


Solids have strong, stiff bonds between molecules that hold the molecules in place.


Liquids have loose, stringy bonds between molecules that hold molecules together but allow them some flexibility.


Gasses have no bonds between the molecules.


Plasma is similar to gas but the molecules are very highly energized. The molecules in this state are moving around so fast that they are knocking electrons off each other, which ionizes the gas (gives the molecules in the gas an electrical charge).


Materials change from one state to another depending on the temperature and these bonds.


Changing from a solid to a liquid is called melting. When enough energy is added to a solid, the atoms start vibrating so hard that they jiggle loose from the solid structure into a liquid form.


Changing from a liquid to a gas is called boiling, evaporating, or vaporizing. When more energy is added to the liquid, the top layer vibrates even faster and breaks free of the liquid state atoms to float off in a gaseous state.


Changing from a gas to a liquid is called condensation. When you pull enough energy from a substance, you slow down the molecules enough that they start to link up with each other.


Changing from a liquid to a solid is called freezing. When enough energy is pulled from the system, the atoms (or molecules) lock into place with strong bonds.


We’ll discover more about matter and the bonds that hold it together (including how to break them!) in Unit 3 and Unit 8 and Unit 15.




Energy

There are many different kinds of energy: kinetic, potential, elastic, chemical, nuclear, electrical, mechanical, thermal…


Energy can be transferred, in other words it can be changed from one form to another and from one object to another.


First Law of Thermodynamics: Energy cannot be created or destroyed in a closed system. A system is the place the energy is happening in.


The terms hot, cold, warm etc. describe what physicists call thermal energy. Thermal energy is how much the molecules are moving inside an object. The faster molecules move, the more thermal energy that object has.


Heat is the movement of thermal energy from one object to another.


Second law of thermodynamics: Heat can only flow from an object of a higher temperature to an object of a lower temperature. Heat can be transferred from one object to another through conduction, convection and radiation.


Imagine your cup of hot coffee on a cold morning… which way does the heat flow? Does your coffee get warmer or cooler over time?


Gravitational potential energy is the amount of energy something has due to its height above the ground. The higher it is and more mass it has the more gravitational potential energy it has.


Kinetic energy is energy of motion. The faster something is moving and/or the more massive it is the more kinetic energy it has.


Imagine a ball dropping and hitting the floor. If the system is closed, that means no energy can get in or escape from the system. The energy the ball started with is the same energy it hit the floor with and transferred to the floor at impact. No energy was created or destroyed, just transferred within the system.


Now here’s a question you may be asking yourself, “If energy is neither created nor destroyed in a closed system then why doesn’t a kid swinging on the playground swing go forever?


Energy is neither created nor destroyed, but it can be transferred into non-useful energy. In the case of the swinging kid (picture a pendulum), every swing loses a little bit of energy, which is why each swing goes slightly less high than the swing before it.


Where does that energy go? To heat. The second law of thermodynamics states basically that eventually all energy ends up as heat. If you could measure it, you’d find that the string, and the weight have a slightly higher temperature then they did when they started due to friction.


Elastic Potential Energy is the energy stored by stretching or compressing something. If you take a rubber band and stretch it out, you’re storing more energy in that rubber band. We’ll cover more on this in Unit 4 and Unit 5.


Airplanes are Heavier than Air… How Do They Fly?

There’s air surrounding us everywhere, all at the same pressure of 14.7 pounds per square inch (psi). (Remember the ping pong ball experiment earlier?)


An interesting thing happens when you change a pocket of air pressure – things start to move. Higher pressure always pushes stuff around. While lower pressure does not “pull,” we think of higher pressure as a “push”. The higher pressure inside a balloon pushes outward and keeps the balloon in a round shape.


When air moves quickly, it doesn’t have time to push on a nearby surface, such as an airplane wing. The air just zooms by, barely having time to touch the surface, so not much air weight gets put on the surface. Less weight means less force on the area, which really means less pressure.


Bermoulli’s Principle: Fast moving air creates low pressure regions. There’s a reason airplane wings are rounded on top and flat on the bottom. The rounded top wing surface makes the air rush by faster than if it were flat.


When you put your thumb over the end of a gardening hose, the water comes out faster when you decrease the size of the opening.


The same thing happens to the air above the wing: the wind rushing by the wing has less space now that the wing is curved, so it zips over the wing faster, and creates a lower pressure area than the air at the bottom of the wing. The faster air travels over a surface, the less time it has to push down on that surface and create pressure.


The reason airplanes fly? There’s more lift (generated from the wings) than weight and more thrust (from the engine) than drag.  We’ll talk a lot more about this in the Flight Lab (released in summer).


Mass and Energy

E=mc2 is the conversion between mass and all energy. This includes nuclear, chemical, electromagnetic, elastic, potential, kinetic, electrical, mechanical, thermal, etc. (not just the energy inside the nucleus).


If you stretch a rubber band, you could measure the mass and find it’s slightly greater than its un-stretched length (if you had a scale sensitive enough).


The extra mass didn’t come from extra atoms, but rather from the energy you put into the rubber band by stretching it. The energy is stored in the electromagnetic forces holding the atoms together, and anything that stores energy will have mass associated with it. We’ve got an entire lesson on this in Unit 7.


Click here to get started with the experiments for this lesson!

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How many of these items do you already have? We’ve tried to keep it simple for you by making the majority of the items things most people have within reach (both physically and budget-wise).


If you find you don’t have something, simply add it to your next errand or shopping store list.


Shopping List for Unit Zero: Overview of eScience


Click here for Shopping List for Unit Zero.


  • Ball (any size)
  • Garden hose attached to a faucet
  • 4 sheets of paper
  • Ping pong ball
  • Small funnel (you can even make one out of a cone of paper)
  • A couple of large latex balloons, un-inflated
  • Assortment of magnets, including two that are rectangular (you’re going to break one)
  • Large nail (at least 2 inches long)
  • Spool of magnet wire
  • D-cell battery
  • Paper clips
  • Compass (any cheap one will work)
  • Glass of water
  • Glow-in-the-dark toy
  • Cup of hot coffee
  • Can of soda

If you've ever wanted to sneak a peek into my cabinet of educational games and books for kids, now is your chance. Use this list for gift ideas, boredom busters, and just plain family fun. Some of these games you can pick up at the store, and the rest are the home-made, print-it-out, cut-and-play variety that your kids will really learn from.

I first made this list because I felt that so many games are watered-down versions of either bingo or "roll the dice and see where you land", with the occasional card pick. I was curious to see if there were any truly great educational games still available, or if they were all just brain candy.

My games listed here are designed to develop strategy, critical thinking, and chaotic surprise in addition to having the kids learn practical knowledge along the way (not trivial fluff). And when a kid memorizes the card deck, it works in their favor because now they know the entire periodic table.

Here you'll find games including arithmetic, fractals, equations, chemistry, physics, and more. If you have any you'd like to add to the pile, just submit it in the comments section so everyone can benefit. Are you ready?

Note: This list is growing so please check back for updates!

Favorite Books

Favorite Resource for Science Supplies

A lot of science supplies can be purchased online these days, especially the hard to find stuff. However, if you're in the market for oddball items from a company that reuses industrial overruns, here it is:

  • RAFT Resource Area For Teaching RAFT (Resource Area For Teaching). When I was first starting out, I would take a pickup truck to RAFT in San Jose and load up on everything I needed to teach science for the month. Since I was teaching at 60 different schools (about 50 classes per week), I went through a LOT of materials... and I knew I had to get them inexpensively. RAFT has grown a lot over the years, and if you've never had the opportunity before, now is your chance to check it out for yourself.
  • Educational Innovations is the place I got a lot of my physics stuff when I was teaching at the university.
  • Sci-Supply is an inexpensive physics store with lots of great stuff for smart kids.
  • Science First is where I get a lot of my higher-end, more commercial grade physics demos.

Favorite Science Games

Math Games

  • Equate the Math version of Scrabble, which is great for kids that are getting the hang of arithmetic
  • Best Dice Game for honing math skills - I keep a set in my purse wherever I go (no kidding!)
  • Monopoly using a third and fourth die to calculate tax for purchases or compound interest (for rate and time); federal income tax brackets (which depend on your capital) replaces the 'income tax' square... we try to make it as realistic as we can, and even do the 'bidding option' stated in the rules when buying property.
  • Mathematician Dice
  • Cryptarithms (one of my favorite math games - it's the image of "SEND MORE MONEY" at the above right - you have to figure out what number each letter represents!)
  • More Math Recommendations

Awesome Games Overall

  • Chess find a 34-piece set (with four queens) and a vinyl mat

Intelligent Music for Kids

(that doesn't make adults want to rip their hair out)

Here's the video of the Element Song:

 

 

Here's the video of the Nano Song:

 

Note: You can find more songs at the Harvard Physics Song site, but be sure to preview them before sharing them with your kids as they are more appropriate for college-level students!

What Pi Sounds Like by Michael Blake (see video below):


Chemical Data & Safe Handling Information Sheet

What do I really need to know first? First of all, the chemicals in this set should be stored out of reach of pets and children. Grab the chemicals right now and stuff them in a safe place where accidents can’t happen. Do this NOW!


If you haven’t already done so, make sure to watch the introductory video for the Intermediate Chemistry and Advanced Chemistry lessons. They contain important information about the chemicals and lab equipment you’ll be using. When you’re done storing your chemicals out of reach, watch this video:


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Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.


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1. Determine the number of moles of N2O4 needed to react completely with 2.56 mol of N2H4 for the reaction:


2 N2H4(l) + N2O4(l) ? 3 N2(g) + 4 H2O(l)


2. When the following reaction begins with 4.52 moles of N2H4, determine the number of moles of N2 produced for the reaction:
2 N2H4(l) + N2O4(l) ? 3 N2(g) + 4 H2O(l)


3. The balanced equation for the synthesis of ammonia is:
3 H2(g) + N2(g) ? 2 NH3(g).


Calculate:
a. the mass in grams of NH3 formed from the reaction of 72.0 g of N2
b. the mass in grams of N2 required for form 3.00 kg of NH3


4. What are the most dangerous chemicals in your C3000 set?


5. After mixing two chemicals together, you observe your solution bubbles, gets warm and turns litmus paper red. What do you know about the solution already?


6. If you cut an apple in half and leave it for ten minutes, it turns brown. Why?
7. Practice balancing the equations below:
a. ___KOH + ____H3PO4 –> ___K3PO4 + ___H2O
b. ___NH3 + ___O2 –>___NO + ___H2O
c. ___BF3 + ___Li2SO4 –> ___B2(SO3)3 + ___LiF


8. How many moles in 26 grams of carbon dioxide?


9. If we have 42 moles of H2SO4, how many grams is that?


10. What’s the difference between an acid-base reaction and a redox reaction?


11. If you want to speed up the rate of a reaction, what could you do?


Need answers?

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Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.


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1. You mix together two chemicals and notice that the outside of the container feels like ice. What type of reaction is it?


2. You test a solution with litmus paper and find that there’s no change in the color of the paper. Is it acidic or basic?


3. You need a source of oxygen for an experiment. How would you generate it? Would you use a catalyst?


4. Your fish tank is registering a pH of 6.8. Is your tank acidic or basic?


5. What type of reaction is a campfire? Nail rusting? Turning lead into gold?


6. You have two test tubes that both contain a clear gas. One is hydrogen, the other oxygen. Which one will ignite with a match? Why doesn’t the other ignite?


7. You have two containers, one with lightweight helium and the other with heavier neon gas. What happens to the temperature of both when you squish the containers down to half their original size?


8. What is the difference between a highly corrosive acid and a strong acid?


9. How many protons are in a copper atom? How many electrons? Neutrons?


10. What’s a ‘mole’? Why bother using the ‘mole’ to measure stuff in chemistry?


11. What are the most dangerous chemicals in your set?


12. What are the most important lab skills to master in this unit?


13. You want to build a vehicle that runs only on sunlight and water (no batteries). Draw out the experiment you would use to get energy from water. What type of chemical reaction are you using?


Need answers?

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Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.


Answers:
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1. Determine the number of moles of N2O4 needed to react completely with 2.56 mol of N2H4 for the reaction


2 N2H4(l) + N2O4(l) ? 3 N2(g) + 4 H2O(l)


Find the relation between moles of N2H4 and N2O4 by using the coefficients of the balanced equation:


2 mol N2H4 is proportional to 1 mol N2O4


Therefore, the conversion factor is 1 mol N2O4/2 mol N2H4:


moles N2O4 = 2.56 mol N2H4 x 1 mol N2O4/2 mol N2H4
moles N2O4 = 1.28 mol N2O4 (answer)


2. Determine the number of moles of N2 produced for the reaction


2 N2H4(l) + N2O4(l) ? 3 N2(g) + 4 H2O(l) when the reaction begins with 4.52 moles of N2H4.


Find the relation between moles of N2H4 and N2 by using the coefficients of the balanced equation:


2 mol N2H4 is proportional to 3 mol N2 In this case, we want to go from moles of N2H4 to moles of N2, so the conversion factor is 3 mol N2/2 mol N2H4:


moles N2 = 4.52 mol N2H4 x 3 mol N2/2 mol N2H4
moles N2 = 6.78 mol N2O4 (answer)


3. The balanced equation for the synthesis of ammonia is 3 H2(g) + N2(g) ? 2 NH3(g). From the balanced equation, it is known that:


1 mol N2 ? 2 mol NH3


Use the periodic table to look of the atomic weights of the elements to calculate the weights of the reactants and products:


1 mol of N2 = 2(14.0 g) = 28.0 g
1 mol of NH3 is 14.0 g + 3(1.0 g) = 17.0 g


These relations can be combined to give the conversion factors needed to calculate the mass in grams of NH3 formed from 72.0 g of N2:


mass NH3 = 72.0 g N2 x 1 mol N2/28.0 g NH2 x 2 mol NH3/1mol NH3 x 17.0 g NH3/1 mol NH3


mass NH3 = 87.43 g NH3 (answer)


To obtain the answer to the second part of the problem, the same conversions are used, in a series of three steps:


(1) grams NH3 ? moles NH3 (1 mol NH3 = 17.0 g NH3)
(2) moles NH3 ? moles N2 (1 mol N2 ? 2 mol NH3)
(3) moles N2 ? grams N2 (1 mol N2 = 28.0 g N2)


mass N2 = 3.00 x 103 g NH3 x 1 mol NH3/17.0 g NH3 x 1 mol N2/2 mol NH3 x 28.0 g N2/1 mol N2


mass N2 = 2.47 kg N2 (answer)


4. The most dangerous chemicals in your set are:


a. C1000 & C3000: Potassium Hexa-cyanoferrate(II) – do not release this back into the environment, as it is harmful to aquatic organisms, , so dispose of in container as directed. Do not inhale the dust, and avoid contact with skin and eyes.


b. C1000 & C3000: Hexamethyl-eneteramine – flammable, do not inhale the dust and avoid contact with skin, always wear protective gloves when handling.


c. C1000 & C3000: Copper Sulfate – wear protective gloves and glasses when handling, very poisonous to aquatic organisms, so dispose of in container as directed. Do not release into environment.


d. C3000: Calcium Hydroxide – do not inhale dust, wear protective gloves and glasses when handling, caustic.


e. C3000: Potassium Permanganate – flammable, wear protective gloves and glasses when handling, very poisonous to aquatic organisms, so dispose of in container as directed. Do not release into environment.


f. C3000: Sodium Hydrogen Sulfate – caustic, wear protective gloves and glasses when handling.


g. C3000: Hydrochloric Acid –wear protective gloves and glasses when handling. You’ll be generating a small amount of a weak solution of this with your experiments, so follow all directions carefully.


h. C3000: Sodium Hydroxide – caustic, wear protective gloves and glasses when handling. You’ll be generating this with your experiments, so follow all directions carefully.


5. After mixing two chemicals together, you observe your solution bubbles (generates a gas), gets warm (exothermic) and turns litmus paper red (acidic).


6. If you cut an apple in half and leave it for ten minutes, it turns brown because the fruit is basically rusting. An enzyme in the fruit (polyphenol oxidase) reacts with the oxygen in the air. You can add lemon juice or other acid to slow this chemical reaction down or by removing the oxygen (by vacuum sealing the fruit). If you cut the apple with a rusty knife, the reaction will occur even faster!


7. The balanced equations are below:
a. 3 KOH + H3PO4 –> K3PO4 + 3 H2O
b. 4 NH3 + 5 O2 –> 4 NO + 6 H2O
c. 2 BF3 + 3 Li2SO4 –> B2(SO3)3 + 6 LiF


8. Let’s figure out how many moles are in 26 grams of CO2. First, we peek at the periodic table and find out the atomic mass of carbon is 12, and the atomic mass for oxygen is 16. Here’s how you find the mass of CO2:


C + 2 (O) –> 12 + 2(16) = 44


So one mole of CO2 weighs 44 grams. This now becomes our conversion factor of (1 mole)/(44 grams) and we use it like this:


Number of moles of CO2 = 26g x (1 mole/44grams) = 0.59 moles


So there are 0.59 moles of CO2 in 26grams.


9. If we have 42 moles of H2SO4, how many grams is that?


First, look up H, S, and O in the periodic table to find their atomic masses: H = 1, S = 32, O = 16. So the atomic mass of H2SO4 is:


H2SO4 –> 2H + S + 4O –> 2(1) + 32 + 4(16) = 98


So one mole of H2SO4 weighs 98 grams. Now use this conversion to find the mass for 42 moles:


Grams of H2SO4 = 42 moles x (98 grams/1mole) = 4.12 kg


So there are 4.12 kg of H2SO4 in 42 moles. (That’s a lot – you’d never use that much!)


10. Redox reactions involve electron transferring between atoms. Hydrogen ions (protons) transfers are found in acid-base reactions.


11. Grind up the reactants into a fine powder, swirl them in a minimal amount of water, raise the temperature of the water, and add an appropriate catalyst.


Here’s why: Increasing the temperature will usually increase the rate of reaction, as the higher the temperature of the reactants, the more kinetic energy is in the system. Putting the reactants in a solution allows them to not only react on all sides of the substance but also allows the reactants the most amount of freedom to mingle and react with each other. A higher concentration of the reactants increases the reaction rates because the number of collisions increase. Fine powders react more quickly than large chunks because there’s more area exposed to react when a substance is in powder form, so surface area plays a role in the reaction rates as well. To speed up a reaction without altering the chemistry of the reaction involves adding a catalyst.


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Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.


Answers:
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1. An endothermic reaction needs energy in order to happen. The energy comes from the molecular bonds itself as they break apart to form new bonds with the new chemicals in the solution.


2. Basic solutions do not change blue litmus paper. They can reverse a piece of litmus paper previously dipped in an acidic solution back to blue.


3. Leave a container of hydrogen peroxide out on the counter and stick a balloon over the neck of the bottle to capture the gas. To speed this reaction, add in a crushed lump of charcoal.


4. The fish tank is acidic. And this pH level is preferred by most fresh water fish.


5. A campfire is a combustion reaction. A nail rusting is a synthesis reaction: the iron (Fe) in a nail combines with oxygen (O2) to form rust, also called iron oxide (Fe2O3). Here’s the chemical equation for this reaction: 2Fe + O2 –> Fe2O3.
Turning lead into gold is a nuclear reaction, not a chemical reaction, as it requires altering the nucleus of an atom using a linear accelerator.


6. The hydrogen ignites when a match is brought to it. The oxygen will not ignite, as oxygen is not a fuel source.


7. Both gases behave the same, no matter what atomic weight they have, so using the Ideal Gas Law, you can estimate that the temperature of both doubles when you squish the containers down to half their original size.


8. Here’s the difference between acid strength and corrosiveness: strong acids are quick to donate protons. Corrosive substances are highly reactive (like the HF example). Even though HF is super-corrosive, it’s not a strong acid because it does not completely dissociate (break apart into H+ and Fl-) in water.


9. Copper has the atomic number 29, which means it has 29 protons in the core and 29 electrons in the shells. The atomic weight of copper is 63.546, so rounding up gives an atomic weight of 64. Since electrons are so lightweight, they really don’t add to the overall mass of the atom compared to the protons and neutrons. The number of protons and neutrons need to add up to give the atomic weight of 64. So the number of neutrons in the nucleus is 64 – 29 = 35.


10. A mole is a unit of measurement, just like inches or meters. Since chemical reactions take place on such a small scale, the unit of the mole was invented to help keep track of the particles interacting with each other. One mole is the amount of a substance that has the same number of particles as found in 12 grams of carbon C-12. How many particles, you ask? 602,214,150,000,000,000,000,000 particles to be precise. Or in shorter notation: 6.022 x 1023 particles. This special number is called Avogadro’s constant, and since “mole” is a lot easier to write than 6.022 x 1023, chemists like to use it to help keep track of the particles in a chemical reaction. It’s a handy way to convert between atoms and grams, or even molecules and grams.


11. The most dangerous chemicals in your set are:


a. C1000 & C3000: Potassium Hexa-cyanoferrate(II) – do not release this back into the environment, as it is harmful to aquatic organisms, , so dispose of in container as directed. Do not inhale the dust, and avoid contact with skin and eyes.


b. C1000 & C3000: Hexamethyl-eneteramine – flammable, do not inhale the dust and avoid contact with skin, always wear protective gloves when handling.


c. C1000 & C3000: Copper Sulfate – wear protective gloves and glasses when handling, very poisonous to aquatic organisms, so dispose of in container as directed. Do not release into environment.


12. The most important lab skills to master in this unit are: don’t eat anything in your chemistry lab, keep children and pets away from your lab, lock up your chemicals safely, learn how to store your chemicals safely, and don’t create large quantities of anything explosive, corrosive, or toxic. Always wear safety equipment and do your experiments in a spot what has plenty of air for ventilation, water and a drain, and a phone.


13. Refer to the Electrolysis experiment to split the water molecule into oxygen and hydrogen. Use a solar cell to provide electricity for the electrochemical cell and capture the gases in individual tanks. When you combine the two gases, you will get water and electricity as an output. This is exactly how a fuel cell works.


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You can go your whole life without paying any attention to the chemistry behind acids and bases. But you use acids and bases all the time! They are all around you. We identify acids and bases by measuring their pH.


Every liquid has a pH. If you pay particular attention to this lab, you will even be able to identify most acids and bases and understand why they do what they do. Acids range from very strong to very weak. The strongest acids will dissolve steel. The weakest acids are in your drink box. The strongest bases behave similarly. They can burn your skin or you can wash your hands with them.


Acid rain is one aspect of low pH that you can see every day if you look for it. This is a strange name, isn’t it? We get rained on all the time. If people were dissolving, if the rain made their skin smoke and burn, you’d think it would make headlines, wouldn’t you? The truth is acid rain is too weak to harm us except in very rare and localized conditions. But it’s hard on limestone buildings.


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Acids are liquids with a pH less than seven. A pH of seven is considered neutral. Bases are liquids with a pH greater than seven.


The combustion of fossil fuels such as oil, gasoline, and coal, create acid rain. Rain, normally at a pH of about 5.6, is always at least slightly acidic. Carbon dioxide is released into the air reacts with moisture in the air to form carbonic acid (HCO3). Sulfur dioxide and nitrogen oxides are released into the air by fossil fuel combustion. They react with the slightly acidic rain and form sulfuric acid (H2SO4) and nitric acid (HNO3).


We’re going to have fun with color changes in this experiment. We will make magic paper that changes color to tell us important things about liquids. It’s called litmus paper.


Litmus is harvested from a plant called a lichen, and bottled up as a powder. We’ll take the powder and make an acid-base indicator with it. Then we will use what we make to test solutions. And if you exercise your mind a bit, you will discover ways to use your litmus paper to discover things about the house and the world around you.


Materials:


  • Test tube rack
  • 2 Test tubes
  • Test tube stopper
  • Distilled water
  • Ruler
  • Litmus powder (MSDS)
  • Measuring spoon
  • Denatured alcohol (MSDS)
  • Pipette
  • Sodium carbonate (Na2CO3) (MSDS)
  • Sodium hydrogen sulfate (NaHSO4) (MSDS) Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.
  • Scissors
  • Filter paper (or paper towel or coffee filter)
  • Impervious surface

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


We will be using a ruler to measure the amount of water in a test tube. Ordinarily, chemists use more accurate measurement tools than a ruler. For the first part of this lab, making litmus solution, all we need is an approximate volume of water.


We will also be shaking a liquid in a test tube. Ever leave the top of a blender off when the “on” button is depressed? If not, just believe that it’s not a good idea. There is a certain technique t use when shaking up a liquid. We’ll place a stopper on a test tube and shake vigorously. Remember to do that as a chemist would do.


In a laboratory, whenever a chemist stoppers a solution and shakes it, it will be done the same way no matter if it is a toxic substance or just salt and water. That way, they are in the habit of doing it one way, the right way, so a mistake is not made at any time. A mistake at the wrong time could even be fatal.


Stopper the test tube firmly. Seat it well, but don’t grind down on the stopper. A test tube is thin-walled glassware, and as we grip harder it could collapse in our hand and now we have open cuts, blood, and toxic chemical is now entering your bloodstream. Stoppered firmly, we hold the test tube in our hand and place our thumb over the stopper for added security. To top off our safety measures, point the test tube, with a thumb firmly on top, away from us or anyone else and shake to our heart’s content.


We need to be careful with our chemicals. After using a chemical, cap the container to prevent spillage and contamination. Clean everything thoroughly after you are finished with the lab, or if you are going to reuse a tool. To dip a measuring spoon into one chemical after another, contaminates the chemicals and will affect your results.


C1000: Experiments 1-10
C3000: Experiments 5-18


Download Student Worksheet & Exercises


Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Place all chemicals, cleaned tools, and glassware in their respective storage places.


Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.


You can test how acidic different substances are with an acid-base indicator like litmus paper.


Using the litmus powder in the chemistry set, we will make litmus paper. Our litmus paper is going to start out blue, and will turn red when an acid is placed on it. You can turn it back to blue by placing a few drops of a basic solution on it.


Let’s look a little further into the chemistry behind acids and bases. An acid produces hydronium ions (example: H3O+) when dissolved in water. The + or notation on a molecule tells us that after a chemical reaction creates it, the molecule is left with a net positive (electrons have been lost) or net negative charge (electrons have been added). Now, the ion could have more than just a +1 or -1 charge. Often, we will discover molecules with positive or negative charges of 2, 3, or 4.


Every liquid has a pH, and some of them may surprise you. Fruits contain citric acid, malic acid, and ascorbic acids, and the distilled white vinegar in your kitchen is a weak form of acetic acid. You’ll find carbonic acids in sodas, and lactic acid in buttermilk. And remember that acids taste sour and bases taste bitter? Don’t taste your chemicals, but the sour taste of vinegar and lemons and the bitter taste of club soda water and baking soda are familiar to people.


Generally, acids are sour in taste, change litmus paper from blue to red, react with metals to produce a metal salt and hydrogen, react with bases to produce a salt and water, and conduct electricity. Strong acids often produce a stinging feeling on mucus membranes (don’t ever taste an acid, or any chemical for that matter!).


Acids are proton donors (they produce H+ ions). Strong acids and bases all have one thing in common: they break apart (completely dissociate) into ions when placed in water.  This means that once you dunk the acid molecule in water, it splits apart and does not exist as a whole molecule in water. Strong acids form H+ and an anion, such as sulfuric acid:


H2SO4 –> H++ HSO4


There are six strong acids:


  • hydrochloric acid (HCl)
  • nitric acid (HNO3) used in fireworks and explosives
  • sulfuric acid (H2SO4) which is the acid in your car battery
  • hydrobromic acid (HBr)
  • hydroiodic acid (HI)
  • perchloric acid (HClO4)

The record-holder for the world’s strongest acid are the carborane superacids (over a million times stronger than concentrated sulfuric acid). Carborane acids are not highly corrosive even though are super-strong. Here’s the difference between acid strength and corrosiveness: the carborane acid is quick to donate protons, making it a super-strong acid.  However, it not as reactive (negatively charged) as hydrofluoric (HF) acid, which is so corrosive that it will dissolve glass, many metals, and most plastics.


What makes the HF so corrosive is the highly reactive Fl ion. Even though HF is super-corrosive, it’s not a strong acid because it does not completely dissociate (break apart into H+ and Fl) in water. Do you see the difference? Weak acids only partly dissociate in water, such as acetic acid (CH3COOH).


On the other hand, bases taste bitter (again, don’t even think about putting these in your mouth!), feel slippery (don’t touch bases with your bare hands!), don’t change the color of litmus paper, but can turn red litmus back to blue, conduct electricity when in a solution, and react with acids to form salts and water. Soaps and detergents are usually bases, along with house cleaning products like ammonia.


Bases are also electron pair donors (they produce OH ions). Strong bases also completely dissociate into the OH (hydroxide ion) and a cation. LiOH (lithium hydroxide), NaOH (sodium hydroxide), KOH (potassium hydroxide), RbOH (rubidium hydroxide), CsOH (cesium hydroxide), Ca(OH)2 (calcium hydroxide), Sr(OH)2 (strontium hydroxide), and Ba(OH)2 (barium hydroxide).  Weak bases only partly dissociate in water, such as ammonia (NH3)


pH stands for “power of hydrogen” and is a measure of how acidic a substance is.  We can make homemade indicators to test how acidic (or basic) something is by squeezing out a special kind of juice (dye) called anthocyanin. Certain flowers have anthocyanin in their petals, which can change color depending on how acidic the soil is (hibiscus, hydrangeas, and marigolds for example).  The more acidic a substance, the more red the indicator will become.


Going Further

Experiment: What household items are acidic or basic? Test various liquids to see. You may be surprised. Liquids you should be sure to test are vinegar, lemon or orange juice, baking soda, and cola. Use a dropper to place drops onto the paper instead of dunking the strip into your entire carton of orange juice. Litmus flavored orange juice is not my first choice in the morning.


Experiment: Collect soil samples from various places. Not the types of plants growing in the immediate area you are sampling from. Place about an inch of dirt in the bottom of a test tube. Fill the test tube near the top with water. Use distilled water if you have it for more accuracy. Stopper the tube and shake vigorously. Use your pipette to place drops of the water on your litmus paper and see if the soil is acidic or basic. Is there a correlation between the acidity of the soil and the plants that grow there?


Note: Litmus paper will not be able to indicate how acidic the rain in your area is, because the acid content in the water droplet is not high enough to register on the indicator. The effects of acid rain take time to develop and require more sensitive equipment to detect. [/am4show]


This experiment is for advanced students.


Purple and white colors, making the whitewash that Tom Sawyer used, and produce an exothermic chemical reaction…..does it get any better?


Limewater is one of the compounds we work with in this experiment. Limewater was used in the old days of America. We’re talking about the 80’s…..the 1880’s.


Traveling medicine shows sold what was called “patent medicines”. These usually had no medicinal properties at all. The man in charge, the salesman of the operation, was called a “huckster”. He would have the one of the people gathered around to listen to him blow into limewater. Their exhaled breath contains carbon dioxide, and the lime water turned cloudy, just like in our experiment.


The man would hold up the glass with the cloudy limewater in it and pour in some of his fantastic remedy. As long as the “medicine” was acidic, it would turn the cloudy limewater clear. This was proof that the remedy would cure whatever ailed the person.


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Today, lime water is used in the traditional making of corn tortillas, tamales, and corn chips. People who have marine (saltwater) aquariums use lime water to assist in maintaining a healthy tank. Lime water is also used in the hide tanning process to remove hair. Parchment paper is made possible by the use of lime water as well. Here’s what you’ll need for your experiment with limewater:


Materials:


  • Granulated white sugar (MSDS)
  • Distilled water
  • Test tube rack
  • 2 test tubes
  • On-hole rubber stopper
  • Measuring spoon
  • 900 bend glass tubing
  • Test tube clamp
  • Potassium permanganate (KMnO4) (MSDS)
  • Sodium hydrogen sulfate (NaHSO4 ) (MSDS) Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.
  • Measuring syringe
  • Calcium hydroxide, Ca(OH)2 (MSDS) to add to H20 to make limewater (MSDS)

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


Keep the potassium permanganate solution from entering the glass tube and being transported into the limewater.


Saturated calcium hydroxide solution has been historically called lime water Ca(OH)2 . That is what we will be bubbling our carbon dioxide into. It looks like water, but isn’t. Limewater smells like dirt and has an alkaline taste. (Don’t taste to find out. Not a safe laboratory practice.)


Saturated calcium hydroxide solution has been used as paint since the early years of the settlement of America. Ever hear of Tom Sawyer and the whitewashed fence? Whitewash is another name for limewater. We’re going to be using some pretty nasty chemicals, but you already follow all the safety precautions. Just remember to remember, and be careful.


The solution in one of your test tubes is going t undergo a chemical reaction to produce carbon dioxide. Another solution will be the indicator that CO2 has been produced.


C3000: Experiment 64


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


When carbon dioxide is produced and bubbled into the lime water, a chemical reaction takes place.


Ca(OH)2 + CO2 –> CaCO3 + H2O


Calcium hydroxide (lime water) and carbon dioxide yields calcium carbonate and water. A milky precipitate forms that is calcium carbonate (CaCO3).


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.


Disposal: Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.


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This experiment is for advanced students. This is a repeat of the experiment: Can Fish Drown? but now we’re going to do this experiment again with your new chemistry glassware.


The aquarium looked normal in every way, except for the fish. They were breathing very fast and sinking head first to the bottom of the tank. They would sink a few inches, then jerk into proper movement again.


The student had to figure out what was wrong. He had set up the aquarium as an ongoing science project, and it was his responsibility to maintain the fish tank. His grade depended on it.


He went to his mom for help. She looked over the setup. “Have you tested the water?”


A quizzical look on his face, the boy said, “Everything is normal nitrates, nitrites, hardness, alkalinity, and pH. The pH was a little acidic, but not outside the proper range.”


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His mother said to him, “Show me how you would look if you were gasping for air and look in the mirror while you do it.”


He did, and he remarked, “I look like my fish.” I swear a light bulb actually appeared over his head and lit all up. He said, “They need air!” His mom was standing near the aquarium holding an air pump, vinyl tubing, and an air stone.


“Looking for this?” His mom said. He and his mom set up the air pump and soon his fish were jumping in the air and kissing him on the cheek. Well, maybe not that last part, but you get the idea. Water does not contain an inexhaustible amount of oxygen in it. It must be replenished if there is something in the water that is using it up.


The oxygen carrying capacity of water varies with conditions. Rainbow trout are found in cold water streams because the colder the water, the more oxygen it will hold. Rainbow trout need lots of oxygen in their water to survive. Other species of fish are found only in warmer water because they are adapted to a condition of less oxygen in the water. Still other fish can gulp the air from the surface if the water is severely depleted of oxygen. I have seen carp gulping air as they swim around in a pond looking for food on a hot summer day.


In this experiment we will discover that water does contain oxygen. We will subject the water to heat and we will see the oxygen for ourselves.


Materials:


  • Test tube rack
  • Test tube
  • Test tube holder
  • Rubber stopper
  • 90 degree bent glass tubing
  • Alcohol burner
  • Striker

Be careful not to let your water boil. Pressure will build up inside the test tube because only a small amount of pressure at a time can leave via the glass tubing. Pressure will build up and the stopper will fly off or the test tube will rupture. (Glass shrapnel and boiling water will get all over you. Not a pleasant thought.)


Inserting the glass tubing into and through the stopper is the most dangerous part of this lab or any other lab requiring this to be done. Most lab injuries, student or chemist, are due to cuts from broken glass. Proper technique will save you the pain of a deep cut. Lubricate the rubber stopper with glycerol if you have it. (It is a non-reactive laboratory grease that will not contaminate as badly as household or automotive oils and greases.) DO NOT use any other grease or oil. You probably don’t have any glycerol, so your second choice is just plain old water.


So, water on the tubing, gently start the glass tubing into the stopper. Don’t grip the glass with your hands, get a thick wash cloth, small towel, or work gloves and grab the tubing. Gently twist the tubing as you push gently on the tubing. Don’t pull to one side or the other, make your push a straight line. Once the tubing gets going, don’t stop unless you have to. Your second shot may be much more difficult because you have pushed a lot of the water off the tubing.


You are not going to see a chemical change. You are not going to work with chemicals. You are going to see for yourself that there is oxygen in water. That is, of course, what fish use up in the water. Unless it is replenished, fish can’t breath and they suffocate….not drown. The oxygen is replenished in the wild through various means. We can replenish the water with air pumps and water changes.


C3000: Experiment 51


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Heated surfaces will be hot for awhile. Let things rest for a couple of minutes before doing your cleanup.


Your test tube probably has a blackened surface. It should wipe off easily, or will with a little soap, water, and a light touch.


Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.


Disposal: Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.


The filter pump in your fish tank ‘aerates’ the water. The simple act of letting water dribble like a waterfall is usually enough to mix air back in. Which is why flowing rivers and streams are popular with fish – all that fresh air getting mixed in must feel good! The constant movement of the river replaces any air lost and the fish stay happy (and breathing). Does it make sense that fish can’t live in stagnant or boiled water?


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This experiment is for advanced students.


Don’t put this in your car….yet. Hydrogen generation, capture, and combustion are big deals right now. The next phase of transportation, and a move away from fossil fuels in not found in electric cars. Electric cars are waiting until hydrogen fuel cell vehicles become practical. It can be done and is being done.


Cars being powered by hydrogen are here, but not on the market yet. Engineers and chemists are always finding new ways to improve the chemical reaction that produces hydrogen and making the vehicles more efficiently use the fuel. Hydrogen fuel is not just easy to make, it is inexpensive, and the “exhaust” is water.


We will generate hydrogen in this lab. We will also see how combustible it is. Just let your imagination wander….just a bit and you will see noiseless cars and trucks zipping along the streets and interstates, carrying people and cargo. The Indianapolis 500 wouldn’t be quite the same, though. “And there they go, roaring, I mean quietly entering turn two…”


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Materials:


  • Goggles
  • Gloves
  • Measuring syringe
  • Water
  • Test tube rack
  • One-hole rubber stopper
  • Alcohol burner
  • Lighter
  • Test tube
  • Test tube holder
  • Water bath
  • Chemistry stand
  • Rubber tubing
  • 90 degree bend glass tubing
  • Zn powder (MSDS)
  • Copper sulfate CuSo4 (MSDS)
  • Sodium hydrogen sulfate NaHSO4 (MSDSSodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


We will combine sodium hydrogen sulfate, water, and zinc. As soon as they are all together in our test tube, bubbles will begin forming in the solution. The bubbles will continue coming off, but we can speed up the reaction by adding a little copper sulfate. Now, instead of leisurely coming off, the gas is being given off quickly and we must act quickly ourselves to capture as much of the gas as possible. We can aid the gas movement ourselves by swirling the solution gently.


C3000: Experiment 74


Here’s what’s going on in this experiment:


NaHSO4 + H2O + Zn + CuSO4 –> H2 + NaSO4 + CuHSO4 + ZnO


Sodium hydrogen sulfate is added to water and dissolved completely. Zinc is added and hydrogen gas is generated by the chemical reaction. Copper sulfate is added as a catalyst to speed up the generation of hydrogen.


Double replacement occurs where the compounds are broken apart and the pieces realign and re-bond with different parts of the original molecules, and zinc oxide is left as a byproduct of the oxidation of the zinc powder. Hydrogen gas is freed in the reaction.


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids must be neutralized before they can be washed down the drain. Solids are thrown in the outside trash.


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This experiment is for advanced students.


In industry, hydrogen peroxide is used in paper making to bleach the pulp before they form it into paper. Biologists, when preparing bones for display, use peroxide to whiten the bones.


At home, 3% peroxide combined with ammonium hydroxide is used to give dark-haired people their desired blonde moment. Peroxide is also used on wounds to clean them and remove dead tissue. Peroxide slows the flow from small blood vessels and oozing in wounds as well.


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Peroxide is a chemical produced in a Bombardier Beetle, and it squirts its irritating load into the face or onto the lips of a predator. Zebra fish produce peroxide after their skin is damaged. This action acts as a signal to produce an abundance of white cells to fight any infection and assist in the healing.


Scientists believe that healing can occur in humans in the same way. Future experiments may prove them right. It is also believed that people who have asthma have elevated levels of peroxide in their lungs, levels much higher than people without asthma.


Hydrogen peroxide can also help an animal that has eaten poison. A small amount of it can be put down the animal’s throat to induce vomiting and clear the poison out of their body as much as possible. Did your dog get too close to a skunk? There is no real “cure” other than a lot of time outside to air out, but peroxide mixed with hand soap is pretty good at removing the stink. Then, how you remove that stink from yourself…..another problem.


Materials:


  • 2 test tubes
  • Burner
  • Lighter
  • Chemistry stand
  • Test tube holder
  • Glass jar
  • Water pan
  • Water
  • Rubber tubing
  • 90o glass tubing
  • 3% Hydrogen peroxide (H2O2) (MSDS)

Hydrogen peroxide comes in a dark bottle because sunlight will slowly decompose hydrogen peroxide in the same way that we are doing with the exception that our way is much quicker.


When finished heating hydrogen peroxide, if you leave everything together, water will climb the tubing and attempt to enter the hot test tube. Cold water and hot peroxide are not safely compatible. To avoid this, remove the stopper from the test tube and set it aside while the solution cools.


Wait until all the equipment is cool enough to touch before disassembling for cleaning and storage.


When heating the test tube, be careful. Don’t heat in one place for too long. Move the flame of the burner around periodically to heat the reaction area of the test tube uniformly.


Don’t boil the peroxide too vigorously. If boiling gets too wild, remove the burner form the test tube until it calms down, then move it back to heat again.


At all times, keep the flame and peroxide apart…well apart.


Hydrogen peroxide is going to get broken down, is going to decompose, into the base elements of hydrogen and oxygen.



Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


Hydrogen peroxide (H2O2) breaks down with heat. A decomposition reaction occurs where hydrogen peroxide breaks down into its component elements, H2 and O2


2H2O2 –> 2H2O + O2


2 molecules of hydrogen peroxide are heated, creating a chemical decomposition reaction, producing 2 molecules of water and 1 molecule of oxygen.


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids can be washed down the drain


Going further: Elephant’s Toothpaste

A really fun experiment with hydrogen peroxide is making Elephant’s toothpaste. It requires an adult helper, and is fun for the kid and the adult.


Materials:


  • Empty 20 or 24 ounce plastic bottle
  • 3 % hydrogen peroxide
  • Liquid dish soap
  • Warm water
  • Food coloring
  • One packet or 2 1/2 ounces of yeast
  • One really big container to contain the big mess – laundry tub, bathtub, etc.

This video below is a demonstration of the Elephant Toothpaste experiment using much nastier chemicals than the ones I’ve mentioned above… the hot gas generated is actually oxygen. Enjoy!



Procedure:


  • Dissolve the yeast in a little warm water and stir well.  Use just enough water to make a pourable liquid.  Let it sit for about 5 minutes while you prepare the rest of the experiment.
  • Pour 1/2 cup of hydrogen peroxide, 1/4 cup of dish soap and a little bit of food coloring in the bottle.  Swirl to mix and put the bottle in the middle of your large pot, container or sink.
  • Pour the yeast solution into the bottle.  A funnel can help, but be prepared to pour fairly quickly and remove it again because the reaction will start as soon as you start pouring.
  • Stand back and watch the fun!

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This experiment is for advanced students.


This time we’re going to use a lot of equipment… really break out all the chemistry stuff. We’ll need all this stuff to generate oxygen with potassium permanganate (KMNO4). We will work with this toxic chemical and we will be careful…won’t we?


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Oxygen is pretty important… it’s only the single most important thing that mammals need. Besides breathing, oxygen is important for so much on this world. Oxygen is used in welding, rocket fuel, and water treatment. Without oxygen, there is no oxidation and no fire. Simply put, we wouldn’t have rusty bicycles or campfires. Can your believe it?


Potassium permanganate is an important chemical in the film industry. It is used to make props like cloth, ropes, and glass, appear “old”. Some films it has been used in are “Troy”, “Indiana Jones”, and “300”. The KMnO4 stains any organic material. KMnO4 is also used as an antiseptic, and is used to treat skin ulcers and rashes. It is also used to treat foot fungus…..phew! People living in the country are sometimes plagued with an iron taste or a rotten egg smell in the water from their wells. Potassium permanganate can be used to remove the taste and smell from the water.


Materials:


  • Chemistry stand
  • Plastic tub
  • Water
  • 2 test tubes
  • Test tube clamp
  • Potassium permanganate (KMnO4) (MSDS)
  • Alcohol burner
  • Lighter
  • One-hole rubber stopper
  • Solid rubber stopper
  • 900 bend glass tube
  • Measuring spoon
  • Rubber tubing
  • Match
  • Wooden splint

Be careful inserting the glass tubing into the stopper. Wet the short end of the glass tube with water and gently push and twist the glass through the stopper. Wear work gloves and work carefully and slowly. Do not use oil or grease you have laying around the house.


When lighting the oxygen in the test tube, use a wooden splint. Wooden splints can be purchased from craft stores, or make your own by shaving thin strips from a piece of pine wood.


C3000: Experiment 58


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


2KMnO4 + O2 –> K2MnO4 + MnO2 + O2


Potassium permanganate is heated and produces potassium manganate, manganese dioxide, and oxygen


Oxygen is generated by heating the KMnO4, and is collected in the test tubes. We will test the contents of the tubes to see if oxygen has been generated. What do you think will happen when a glowing splint is pushed up inside the test tube? Don’t know? Do the experiment and try to figure it out. Remember, in order for there to be flame, you need fuel and oxygen. If that gas was carbon dioxide, what would happen when the glowing splint was placed inside?


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.


Disposal: Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.


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This experiment is for advanced students.


Zinc (Zn), is a metal and it is found as element #30 on the periodic table. We need a little zinc to keep our bodies balanced, but too much is very dangerous.


Zinc is just like the common, everyday substance that we all know as di-hydrogen monoxide (which is the chemical name for water). We need water to survive, but too much will kill us.


DHMO: In chemistry, “Di” equals the number 2; hydrogen is H; mono equals the number one; and oxide is derived from oxygen, and its symbol is O. Put these together and you have Di-hydrogen (H2), and mono oxygen (O). Put them together, what do you have? Water!


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Materials:


  • Goggles
  • Gloves
  • Test tube rack
  • 3 test tubes
  • Burner
  • Lighter
  • Zinc powder (Zn) (MSDS)
  • Calcium hydroxide (Ca(OH)2 (MSDS)
  • Rubber tubing
  • Measuring spoon
  • Solid rubber stopper
  • Pan
  • Water
  • Chemistry stand
  • Test tube holder
  • 90o glass tubing
  • One-hole rubber stopper
  • Evaporating dish
  • Dish soap
  • Wood splint
  • Measuring syringe

Be careful of the hot test tubes! It may not look hot, but don’t find out the hard way. If a chemist wants to know if something is hot, he places the back of his hand near the surface. If he feels heat, he concludes that it is hot. That’s the same way we test a person’s forehead for a fever. The back of your hand is more sensitive than the front.


Zinc, zinc oxide, and calcium hydroxide are dangerous chemicals. Use your safety equipment. Dispose of the residue in the test tube in the outside garbage.


We will be creating hydrogen gas by making a heterogeneous mixture of zinc powder and calcium hydroxide and heat it. The hydrogen bubbles into test tube in a water bath. When we mix our test tube of hydrogen with the air the room, the hydrogen burns…it actually explodes. Our amounts are small, but you will witness a cool, small, explosion.


In the second part of the lab we will again create hydrogen. This time, we have a tricky way to add oxygen to the hydrogen and we are able to create a ration of 2 parts hydrogen to 1 part oxygen. This is the perfect ratio to make the most explosive mixture of hydrogen and oxygen. The explosion here is very cool.


C3000: Experiment 76-78


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


In the first part of the lab we produce hydrogen by combining two dry chemicals and heating them. Now two things will happen. Calcium hydroxide, when heated, produces water.


Ca(OH)2 –> CaO + H2O


Calcium hydroxide, when heated, produces calcium oxide and water. This is an oxidation reaction because the calcium oxidizes….combines with the oxygen and releases the other elements.


Next, Zinc will react with water created by calcium hydroxide. As the Ca(OH)2 is heated and turns to water and calcium oxide, the zinc then reacts and produces zinc oxide and hydrogen gas.


Zn + H2O –> ZnO + H2


Zinc when heated in the presence of water, produces zinc oxide and hydrogen gas. This is a single replacement reaction as oxygen kicks out hydrogen and replaces it with zinc.


Here’s the safety information for the products of the reaction:


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more. Dry all equipment.


Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.


Disposal: Dispose of all solid waste in the outside garbage. Liquids can be washed down the drain.


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This experiment is for advanced students.


Lewis and Clark did this same experiment when they reached the Oregon coast in 1805. Men from the expedition traveled fifteen miles south of the fort they had built at the mouth of the Columbia River to where Seaside, Oregon now thrives.


In 1805, however, it was just men from the fort and Indians. They built an oven of rocks. For six weeks, they processed 1,400 gallons of seawater, boiling the water off to gain 28 gallons of salt.


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Lewis and Clark National Historic Park commemorates the struggles of the expedition. (The reconstructed fort is also there to visit.) It is Fort Clatsop National Memorial, and is quite an experience to go through the fort.


Lewis and Clark went to great lengths to obtain salt. The men had been complaining that fish without salt had become something to avoid. Salt is important to us as well. It is a condiment, an addition to food that brings out the food’s natural flavor. Besides its food value, salt is used as a food preservative. It destroys bacteria in food by removing moisture from their “bodies” and killing them.


Sodium chloride, table salt, NaCl….they’re all acceptable names for salt. If NaCl is broken down into its component elements, the elements don’t act like our friend salt. Its components are sodium and chlorine.


Sodium is a highly reactive alkali metal, element #11 on the periodic table. It is exothermic in water, which means that is gives of heat as it reacts with water. Small pieces tossed into water will react with it. The sodium particles give off heat that melts them into round balls. The sodium particles bounce and scurry around the surface at a high rate of speed. If you ever get the chance to observe this, do it. The reaction continues until the sodium is gone. Sodium, as it reacts with the water, changes chemically into sodium hydroxide. These cool things that sodium does are also dangerous. Sodium and sodium hydroxide are caustic…they are so pH basic that they will burn you.


Chlorine is a halogen, group 17, element #17. Chlorine is used in bleach, disinfectants, and in swimming pool maintenance. It seems that anywhere you want to remove color or life, chlorine is your element. This property of chlorine to kill was used in war. (It would react with the mucous linings in their throat, undergoing a chemical reaction to turn into hydrochloric acid in their throats. Hydrochloric acid is a very dangerous acid, usually fatal once inside you.) Chlorine is known as bleach at home. Never, never, drink it or breathe its fumes.


Materials:


  • Goggles
  • Gloves
  • Jar or glass
  • 2 90o glass tubes
  • Chemistry stand
  • Rubber tubing
  • Test tube clamp
  • Erlenmeyer flask
  • One-hole rubber stopper
  • Wire screen
  • Alcohol burner
  • Lighter
  • Test tube
  • Water
  • Saltwater
  • Heating rod

Look out for the hot flask and other glassware. Allow everything to cool before cleaning.


When done heating, move the rubber tubing out of the water. There is a difference in pressure between the heated glassware and the water bath. That difference in pressure will cause the water to enter the tubing and cool water will flow into the hot glassware and could cause catastrophic damage to the glassware.


Never…Never!….drink the results of an experiment. Yeah, I know that plain old water is supposed to be in the test tube, but follow the experiment’s safety guidelines. You’ve had other stuff in that test tube, too.


C3000: Experiment 83


Here’s what’s going on in this experiment:


That flask of saltwater will start to boil, and water vapor will leave the flask and travel to the test tube. There is no chemical change occurring in this experiment, but a physical one. A physical change involves a change in state (melting, freezing, vaporization, condensation, sublimation). Physical changes are things like crushing a can, melting an ice cube, breaking a bottle, or boiling saltwater until there is nothing left but salt and steam.


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids can be washed down the drain


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This experiment is for advanced students.


Glo-sticks! Parents hang them from their trick or treaters, backpackers read with them light late at night in a tent. Glo-sticks work on the principle of chemiluminescence.  Chemiluminescence is defined as emitting light without heat as the result of a chemical reaction.


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We might be tempted to mistake cold light for fluorescence. Fluorescent light is created by exciting electrons, not from a chemical reaction.


Luminol is one of out chemicals in this lab. Luminol is most famous by its use by criminal investigators when they need to locate blood. What makes this happen is that the iron in the blood reacts with the luminol to generate cold light.


Let’s have fun creating our own little version of cold light….I’ll use the term “cold light” from now on. It takes a long time to type out “chemiluminescence”.


Materials:


  • Glass jar
  • Measuring cup
  • Water
  • Test tube
  • Luminol C8H7N3O2 (MSDS)
  • Sodium hydroxide NaOH (MSDS)
  • Stir rod
  • Hydrogen peroxide H2O2 (MSDS)
  • Potassium hexacynoferrate II    K3Fe(CN)6 (MSDS)
  • Measuring spoon

The chemical reaction in this lab produces light without heat. Photons of light are emitted, but no heat. That must be cold heat. The light emitted from this lab is not as bright as a glow stick, but it still emits light. The same principle is used in the glow sticks. Our light will be seen as a low power blue-green light. The cold light effect is best viewed in a darkened room.


C3000: Experiments: 105, 110


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


Solution #1 C8H7N3O2 + NaOH is added to Solution #2 H2O2 + K3Fe(CN)6 –> Cold Light


Cold Light is the production of light from a chemical reaction without the radiation of heat. There are three types of cold light reactions: Fluorescence, phosphorescence, and chemiluminescence. In chemiluminescence no radiation is absorbed. A chemical reaction provides the energy needed to emit light. Chemiluminescence is usually referred to as “cold light”. It rolls off the tongue much better and is easier to type. (I find that every time I type “chemiluminescence” I spell it differently.)


People used to rub their walking sticks with a luminescent jellyfish to light the path while walking. Today, light sticks from the store aren’t made from jellyfish. Modern-day light sticks involve a different reaction from the experiment you will be performing. We will have the luminal glow, but light sticks use a different reaction.


Light sticks use a di-ester of hydrogen peroxide that oxidizes in an organic solvent. The reaction is tons slower, giving a light stick a life span of hours instead of seconds or minutes. Dyes are added to produce different colors. When you break the class vial inside to activate the light stick, you mix the luminol with the other reactant, and the chemical reaction is under way.


A general chemical equation producing cold light:


A + B –> high energy intermediate à products + light


The luminol is oxidized by B. This oxidation produces cold light.


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids can be washed down the drain. Solids are thrown in the trash.


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This experiment is for advanced students. This lab builds on concepts from the previous carbon dioxide lab.


Limewater….carbon dioxide…indicators. We don’t know too much about these things. Sure, we know a little. Carbon dioxide is exhaled by us and plants need it to grow. Burning fossil fuels produces carbon dioxide.


Indicators…something we observe that confirms to us that something specific is happening. Lime water turns cloudy and forms a precipitate in the presence of carbon dioxide. Blue litmus paper turns red in the presence of an acid. The dog barking at the door and dancing around indicates that you better let the dog out, and quick, to avoid….a pet spill?


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Materials:


  • Limewater from a previous lab (MSDS)
  • One-hole rubber stopper
  • 900 bend glass tubing
  • Test tube rack
  • 2 Test tubes
  • Sodium hydrogen sulfate (NaHSO4) (MSDS) Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.
  • Sodium carbonate (Na2CO3) (MSDS)

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


When pouring our limewater into the test tube, be careful! Limewater is dangerous to your skin and your nasal passages. Pour just the limewater into the test tube, not any solids that may have gotten into the limewater container.


A chemical reaction will occur between sodium hydrogen sulfate, sodium carbonate, and water. We could have used any combination of chemicals for this lab that will produce carbon dioxide (CO2), but these chemicals are already in our kits, so……


The reaction will create a gas, that gas, we think, is carbon dioxide. If we are right, we will be bubbling CO2 gas into lime water. If we observe the limewater becoming cloudy and if a precipitate forms on the bottom of the test tube, that is a positive indicator that CO2 is present.


C3000: Experiment 31


Here’s what’s going on in this experiment:


Some combination of chemicals will produce carbon dioxide –> CO2 + ?


Notice that specific chemicals are not in the chemical equation? The actual chemistry of the chemical reaction is not our focus in this lab. We want to experience how an indicator can test for a particular compound or element.


Instead of sodium hydroxide and sodium carbonate and water, we could choose to combine vinegar and baking soda for example. Even simple household supplies can be chemicals for our experiments.


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids can be washed down the drain. Solids are thrown in the trash.


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This experiment is for advanced students.


Who gets to burn something today? YOU get to burn something today!


You will be working with Zinc (Zn). Other labs in this kit allow us to burn metal, but there is a bit of a twist this time. We will be burning a powder.


Why a powder instead of a solid ribbon or foil as in the other labs?  Have you heard of surface area being a factor in a chemical reaction? The more surface area there is to burn, the more dramatic the chemical change. So, with this fact in mind, a powder should burn faster or be more likely to burn than a large solid.


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Zinc (Zn) is a metallic element. It is element #30 on the periodic table. Chemically, it is similar to magnesium, another element that we use in our experiments.


Brass is an alloy of zinc and copper. Brass has been an important metal since the 10th century B.C. Alchemists in the dark ages burned zinc in air, just like we will do, to make what they called “white snow”. Their “white snow is our zinc oxide.


Zinc is an important element in our lives. Zinc deficiency causes lack of proper growth, delayed physical maturation, and susceptibility to infection. Zinc deficiency contributes to the death of 800,000 children per year. Excess zinc in our bodies can cause problems for us as well.


Materials:


  • Alcohol burner
  • Lighter
  • Measuring spoon
  • Zinc powder (MSDS)
  • Porcelain tile work surface

Remember to dispose of your zinc oxide in the outside trash, and conduct your experiment in a well ventilated area. Fumes from this experiment are irritating and a little dangerous.


C3000: Experiment 53


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


Zinc powder will burn in the presence of oxygen, producing interesting colors. The flame from burning zinc is blue, as the zinc undergoes a chemical change to become zinc oxide. Zinc oxide is thermochromic. That means that it changes colors depending on the temperature. When cool, ZnO is white. When heated, zinc oxide turns yellow, and as it cools, returns to become a white powder again. The color changes are caused by a small loss of oxygen at high temperatures, and a small gain of oxygen as it cools in air.


2Zn + O2 –> 2ZnO


Zinc powder burned in air reacts with the oxygen and turns into zinc oxide. Zinc oxide is used in sunscreen and to treat burns, cuts, and diaper rash.


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place all chemicals and cleaned tools, and glassware in their respective storage places.


Disposal: Dispose of all solid waste in the garbage.


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Magnesium is one of the most common elements in the Earth’s crust. This alkaline earth metal is silvery white, and soft. As you perform this lab, think about why magnesium is used in emergency flares and fireworks. Farmers use it in fertilizers, pharmacists use it in laxatives and antacids, and engineers mix it with aluminum to create the BMW N52 6-cylinder magnesium engine block. Photographers used to use magnesium powder in the camera’s flash before xenon bulbs were available.


Most folks, however, equate magnesium with a burning white flame. Magnesium fires burn too hot to be extinguished using water, so most firefighters use sand or graphite.


We’re going to learn how to (safely) ignite a piece of magnesium in the first experiment, and next how to get energy from it by using it in a battery in the second experiment. Are you ready?


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Materials:


  • magnesium strip (MSDS)
  • matches with adult help
  • tile or concrete surface (something non-flammable)
  • gloves, goggles

Burning magnesium produces ultraviolet light. This isn’t good for your eyes, and the brightness of the flame is another danger for your eyes. Avoid looking directly into the flame.


Burning magnesium is so hot that if it gets on your skin it will burn to it and not come off. As difficult as burning magnesium is to put out, avoid letting the burning metal come in contact with you or anything else that might catch fire.


As explained later in this lab, magnesium burns in carbon dioxide. Therefore, a CO2 fire extinguisher won’t work to put it out. Water won’t work, CO2 won’t work. It takes a dry chemical fire extinguisher to put it out, or just wait for it to burn up completely on its own.


Magnesium is a metal, and in this experiment, you’ll find that some metals can burn. The magnesium in this first experiment combines with the oxygen in the air to produce a highly exothermic reaction (gives off heat and light). The ash left from this experiment is magnesium oxide:


2Mg (s) + O2 (g) –> 2Mg O (s)


Not all the magnesium from this experiment turned directly into the ash on the table – some of it transformed into the smoke that escaped into the air.


Caution: Do NOT look directly at the white flame (which also contains UV), and do NOT inhale the smoke from this experiment!


C3000: Experiment 52


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


As you burn your magnesium, you will get your very own fireworks show….a little one, but still cool.


2Mg + O2 –> 2MgO


Magnesium burned in oxygen yields magnesium oxide. Because the temperature of burning magnesium is so high, small amounts of magnesium react with nitrogen in the air and produce magnesium nitride.


3Mg + N2 –> 2Mg3N2


Magnesium plus nitrogen yield magnesium nitride.  Magnesium will also burn in a beaker of dry ice instead of in air (oxygen).


2Mg + CO2 –> 2MgO + C


Magnesium burned in carbon dioxide yields magnesium oxide and carbon (ash, charcoal, etc.)


Cleanup: Rinse off and pat dry the rest of the magnesium strip.


Storage: Place everything back in its proper place in your chemistry set.


Disposal: Dispose of all solid waste in the garbage.


Magnesium Battery

Now let’s see how to make a battery using magnesium, table salt, copper wire, and sodium hydrogen sulfate (AKA sodium bisulfate).


Materials:


  • magnesium strip
  • test tube and rack
  • light bulb (from a flashlight)
  • 2 pieces of wire
  • measuring cup of water
  • salt (sodium chloride)
  • copper wire (no insulation, solid core)
  • measuring spoon
  • sodium hydrogen sulfate (NaHSO4) (MSDS) Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.
  • gloves, goggles

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.

C1000: Experiment 75
C3000: Experiment 295


We’re going to do another electrolysis experiment, but this time using magnesium instead of zinc. In the previous electrolysis experiment, we used electrical energy to start a chemical reaction, but this time we’re going to use chemical energy to generate electricity.  Using two electrodes, magnesium and copper, we can create a voltaic cell.


TIP: Use sandpaper to scuff up the surfaces of the copper and magnesium so they are fresh and oxide-free for this experiment.  And do this experiment in a DARK room.


How cool is it to generate electricity from a few strips of metal and salt water? Pretty neat! This is the way carbon-core batteries work (the super-cheap brands labeled ‘Heavy Duty’ are carbon-zinc or ‘dry cell’ batteries). However, in dry cell batteries scientists use a crumbly paste instead of a watery solution (hence the name) by mixing in additives.


In this chemical reaction, when the magnesium metal enters into the solution, it leaves 2 electrons behind and turns into a magnesium ion:


Oxidation: Mg (s) –> Mg2+(aq) + 2e


The magnesium strip takes on a negative charge (cathode), and the copper strip takes on a positive charge (anode).  The copper strip snatches up the electrons:


Reduction: Cu2+(aq) + 2e –> Cu (s)


and you have a flow of electrons that run through the wire from surplus (cathode) to shortage (anode), which lights up the bulb.


Note: You can substitute a zinc strip or aluminum strip for the magnesium strip and a carbon rod (from a pencil) for the copper wire.


Going further: You can expand on this experiment by substituting copper sulfate and a salt bridge to make a voltaic cell from two half-cells in Experiment 16.5 of the Illustrated Guide to Home Chemistry Experiments.


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This experiment is for advanced students.


Brimstone is another name for sulfur, and if you’ve ever smelled it burn…..whoa….I’m telling you ….you will see for yourself in this lab. It is quite a smell, for sure. Sulfur is element #6 on the periodic table. Sulfur is used in fertilizer, black powder, matches, and insecticides. In pioneer times sulfur was put into patent medicines and used as a laxative.


To further the evil reputation of sulfur, or brimstone, when sulfur is burned in a coal fired power plant, sulfur dioxide is produced. The sulfur is spewed into the air, where it is reacts with moisture in the air to form sulfuric acid. The clouds get full and need to let go of this sulfuric acid. Down comes the acid rain to wreak havoc on the masonry and plant life below.


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Materials:


  • Goggles
  • Gloves
  • Measuring spoon
  • Sulfur (MSDS)
  • Alcohol burner
  • Lighter
  • Test tube of O2

Be careful when bending the ends of your measuring spoon. Bend them where you need them and leave them alone. Continuing to bend, straighten, and re-bend will weaken the metal and cause your measuring spoon to break. We will do this experiment to compare the flames produced by burning sulfur in air and oxygen


C3000: Experiments: 36,60


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


S + O2 –> SO2


Sulfur and oxygen are heated and sulfur dioxide is produced. This is a synthesis reaction because the sulfur and the oxygen react and form a new substance, sulfur dioxide. We see the flame of sulfur dioxide burn in air. Small flame, little smoke. When the flame is left lit and placed in the oxygen, the flame flares up and lots of white smoke is generated. It appears that sulfur’s flame burns brighter and stronger in pure oxygen.


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids can be washed down the drain. Solids are thrown in the trash.


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In this lab, we’re going to investigate the wonders of electrochemistry. Electrochemistry became a new branch of chemistry in 1832, founded by Michael Faraday. Michael Faraday is considered the “father of electrochemistry”. The knowledge gained from his work has filtered down to this lab. YOU will be like Michael Faraday. I imagined he would have been overjoyed to do this lab and see the results. You are soooo lucky to be able to take an active part in this experiment. Here’s what you’re going to do…


You will be “creating” metallic copper from a solution of copper sulfate and water, and depositing it on a negative electrode. Copper is one of our more interesting elements. Copper is a metal, and element 29 on your periodic table. It conducts heat and electricity very well.


Many things around you are made of copper. Copper wire is used in electrical wiring. It has been used for centuries in the form of pipes to distribute water and other fluids in homes and in industry. The Statue of Liberty is a wonderful example of how beautiful 180,000 pounds of copper can be. Yes, it is made of copper, and no, it doesn’t look like a penny…..on the surface. The green color is copper oxide, which forms on the surface of copper exposed to air and water. The oxide is formed on the surface and does not attack the bulk of the copper. You could say that copper oxide protects the copper.


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Our bodies use copper to our advantage, but in a proper form that is not toxic. Too much copper will make you sick and could kill you. Remember…don’t eat your chemistry set!


Materials:


  • Carbon rod (MSDS)
  • Copper sulfate (CuSo4) (MSDS)
  • Aluminum foil
  • 9V battery with clip
  • 2 wires
  • Disposable cup
  • Water

You are going to make a saturated solution of copper sulfate (CuSO4) in water. Pour a measuring spoon of granulated copper sulfate in the measuring cup of water. Stir well. Continue adding a spoonful and stirring until no more crystals will go into solution. The solution is saturated when no more crystals will dissolve and there are undissolved crystals at the bottom of the container.


C1000: Experiment 74

C3000: Experiment 121, 289


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


CuSO4 + H2O (Copper sulfate is added to water)


CuSO4 + H2O à Cu2+ + SO42- (Copper sulfate plus water yields positively charged carbon ion and negatively charged sulfate ion)


When mixed with water, copper sulfate dissociates into copper and sulfate ions. Notice that the ions, now separated, take on negative and positive charges.


Next, 9V of electricity is passed through the solution with an electrode of carbon and an electrode of aluminum foil inserted into the solution. As electricity flows from one electrode to another, the copper ions, being positively charged, are attracted to the negative electrode. You can confirm this in two ways. One, if litmus paper, held close to an electrode, turns blue, that is the negative electrode. The other way is to just follow the negative lead from the battery to the negative electrode.


As the process moves along, the negative electrode gains copper ions. Evidence of this is seen on the surface of the electrode.


Here’s the breakdown of the entire process:

When the copper sulfate (CuSO4) mixed with water (H2O), the copper sulfate dissociated:


CuSO4 –> Cu2+ + SO42-


When power is added to the solution, the copper ions move toward the negative cathode (carbon rod) and take electrons from it, forming solid copper right on the electrode:


Cu2++ 2e –> Cu(s)


On the positive anode (the aluminum foil), you’ll see bubbles instead of a solid forming. The anode attracted electrons from the water molecule to form oxygen bubbles:


6H2O –> O2 + 4H3O+ + 4e


Let’s put these two reactions together to get the overall reaction of:


2Cu2+ + 6H2O –> 2Cu + O2 + 4H3O+


Note the difference between galvanic cells and electrolytic cells: galvanic use spontaneous chemical reactions (like in a car battery) to generate electricity, and electrolytic cells use electricity to make the chemical reaction to occur and move electrons to move in a way they would go on their own (like in this experiment).


Clean up: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. Rinse three times, wash with soap, rinse three times.


Wipe off the carbon rod to remove the copper. The aluminum goes in the trash, but the solution and solids at the bottom cannot. The liquid contains copper, a toxic heavy metal that needs proper disposal and safety precautions. Another chemical reaction needs to be performed to remove the heavy metal from the copper sulfate.  Add a thumb sized piece of steel wool to the solution. The chemical reaction will pull out the copper out of the solution. The liquid can be washed down the drain. The solids cannot be washed down the drain, but they can be put in the trash. Use a little water to rinse the container free of the solids.


Place all chemicals, cleaned tools, and glassware in their respective storage places.


Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.


Going Further

Here is a link to information about making your own geode (crystal lined rock) of copper sulfate crystals:


http://chemistry.about.com/od/growingcrystals/ht/geode.htm


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If we don’t have salt, we die. It’s that simple. The chemical formula for salt is NaCl. Broken down, we have Na (sodium) and Cl (chlorine). Either one of these can be fatal in sufficient quantities. When chemically combined, these two deadly elements become table salt. What once could kill now keeps us alive. Isn’t chemistry awesome?


Chlorine, element 17, is called a halogen as are all the elements in the 17th row. All halogens have similar chemical properties. They are highly reactive nonmetals, and react easily with most metals. Sodium is a metal, and is bonded with sodium in the table salt used in this lab. Besides being found in salt, chlorine has many uses in our world such as killing bacteria in our water, making plastic, cleaning products, and the list goes on. A very useful chemical, and is among the top ten chemicals produced in the United States. Ever since its discovery in 1774, chlorine has been very useful. It is found in nature in sodium chloride, but in very small concentrations. Seawater, the most abundant source of chlorine, has a concentration of only 19g of chlorine per liter.


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Although chlorine is abundant in nature (about 2% of the mass of the ocean is chloride ions), scientists have developed a safe way to make chlorine. Chlorine has been manufactured for a hundred years through different processes: Membrane Cell, Diaphragm Cell, and Mercury Cell processes. In the first two processes, salt water (NaCl + H2O) and caustic soda (NaOH) are used along with a power supply to generate chlorine and hydrogen gas.


Molecules that contain chlorine that find their way into the upper atmosphere can destroy the ozone layer. The ozone-oxygen cycle is a chemical process that transforms the harmful UV light (240-310nm) from the sun into heat. The oxygen and ozone molecules are constantly being switched back and forth as the sun’s UV breaks down the ozone and the oxygen molecules reacts with other oxygen atoms.


This reaction converts UV radiation into thermal energy which heats up the atmosphere (this reaction happens slowly):


O3 –> O2 + O


If two free oxygen atoms meet, they form a new oxygen molecule:


2O –> O2


If this new molecule meets another free oxygen, it creates another ozone molecule:


O2 + O –> O3


If an ozone and an oxygen molecule meet, they form two oxygen, and this process removes ozone from the atmosphere. This process is very slow, however, so the naturally occurring reaction of:


O3 + O –> 2O2


is nothing to worry about. It’s when this reaction gets sped up by catalysts that we have to pay close attention. There are many catalysts that can speed up the removal of ozone, such as chlorine, bromine, and nitric oxide (NO3). And since they are catalysts in the reaction (meaning they simply speed up the reaction without getting used), they can do this over and over again before they move out of the atmosphere completely. One chlorine atom can speed up (catalyze) tens of thousands of ozone removal reactions before it moves out of the stratosphere. Scary, huh?


CFCs (chlorofluorocarbons) such as aerosols, refrigerants (R-12), and solvents have been banned because of their damaging effect on the atmosphere. When sunlight hits a CFC, it splits off a chlorine ion:


CCl3F –> CCl2F + Cl


This free chlorine ion catalyzes the ozone into oxygen:


O3 + O + Cl –> 2 O2 + Cl


The chlorine we’re going to generate in our experiment is a minuscule amount. Even so, it is still a good idea to perform this experiment in an area with good ventilation or outdoors.


Remember to wear your gloves and goggles. True, the amount of chlorine produced is small and pretty harmless. But there are several factors that make it prudent to wear your protection. Not everyone has the same sensitivity to chemicals. Even in this lab, a person could get their skin irritated to some degree. Eyes are very sensitive organs, and I know I don’t want any amount of chlorine contacting my eyes.


Here’s what you’re going to need to do this experiment:


Materials:


  • 9V battery clip
  • carbon rod
  • wires
  • disposable cup
  • salt
  • water
  • aluminum foil
  • gloves, goggles

We will be observing a decomposition reaction. A decomposition reaction separates a substance into two or more substances that may differ from each other and from the original substance.


ZcQr –> Zc + Qr


When separated, the free elements to the right of the equation become ions, one positively charged and one negatively charged.


A very important concept to learn in this lab is that charged particles (ions) will move toward either a positive or negative electrode. The ions that move toward the anode (positive terminal) are anions, and the ones that move toward the cathode (negative) are cations.


Decomposition of any kind is the breaking down of the whole into smaller parts that were once part of the whole.



Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


An electrical charge is passing through a saturated solution of salt (NaCl). It will sit there and just be salt unless that electrical charge is imposed on it. The electrical charge excites the molecules, and causes the molecules of salt to decompose, to pull apart, to break into simpler parts. These ions are negatively and positively charged. Negatively charges particles have more electrons than protons and seek a balance. In order to have an electric current, you need to have positive and negative electrodes. Opposites attract, so the negative ions move to the positive electrode and the positive ions are attracted to the negative electrode.


NaCl –> Na+ + Cl


Sodium chloride decomposes into sodium and chlorine ions.


The anode (positive, carbon rod) soaks up free electrons, which get pumped to the cathode (negative, aluminum foil) and released into the solution. If you press litmus paper against the aluminum strip, you’ll find it’s blue (basic), and red when pressed to the anode (carbon rod). The bubbles on the carbon rod are made of chlorine. The chlorine ions in the solution are attracted to the positive pole (carbon rod) and quickly combine to form chlorine gas:


2Cl –> Cl2


The sodium ions move toward the aluminum foil and split the water molecule into ions:


H2O –> H+ + OH


The hydrogen ions are converted into hydrogen gas:


2H+ –> H2


The sodium ions (Na+) that remain in the solution combine with the OH- ions to create sodium hydroxide which turns the litmus paper blue:


Na+ + OH –> NaOH


The main concept I want you to understand with this experiment is that charged particles (ions) will move toward either a positive or negative electrode. The ions that move toward the anode (positive terminal) are anions, and the ones that move toward the cathode (negative) are cations.


Before you dispose of the solution, try this variation on the experiment: remove the foil and hold a salt-water filled test tube (filled to the top with salt water and capped with a gloved thumb and submerged into the solution). Place the cathode wire into the tube and you’ll see bubbles rising up into the tube. What type of gas is it? (Hint: wait until the tube is nearly full before removing it and using a match to test.)


For C3000 Students: Use this experiment as the basis for Experiment 123.


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.


Disposal: Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.


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Electricity. Chemistry. Nothing in common, have nothing to do with each other. Wrong! Electrochemistry has been a fact since 1774. Once electricity was applied to particular solutions, changes occurred that scientists of the time did not expect.


In this lab, we will discover some of the same things that Farraday found over 300 years ago. We will be there as things tear apart, particles rush about, and the power of attraction is very strong. We’re not talking about dancing, we’re talking about something much more important and interesting….we’re talking about ELECTROCHEMISTRY!


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Materials:


  • Test tube rack
  • 9V battery clip
  • 9V battery
  • Flashlight lamp
  • Gloves
  • Electrical wires
  • Aluminum foil
  • Water
  • Sugar
  • Salt
  • Sodium carbonate (MSDS)
  • Measuring spoon

When the salt sodium chloride (NaCl) mixes with water, it separates into its positively (Na+) and negatively (Cl-) charged particles (ions). When a substance mixes with water and separates into its positive and negative parts, it’s called a ‘salt’.


Salts can be any color of the rainbow, from the deep orange of potassium dichromate to the vivid purple of potassium permanganate to the inky black of manganese dioxide. Did you know that MSG (monosodium glutamate) is a salt? Most salts are not consumable, as in the lead poisoning you’d get if you ingested lead diacetate.


If you pass a current through the solution of salt and water, opposites attract: the positive ions are attracted tot he negative pole and the negative ions go toward the positive pole. These migrations ions allow electricity to flow, which is why ‘salt’ solutions conduct electricity.


C1000: Experiments 66-70


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


Our experiment uses a saturated solution of table salt that is just sitting in a container minding its own business. That just won’t do! We must intervene. Our 9V battery pushes its voltage through the saltwater. That electric current tears the sodium from the chlorine. These positively and negatively charged ions rush about, looking for something they are attracted to. Opposites attract, so positively charged sodium ions find spending time with the negative electrode a treat. They are very happy together. Negatively charged chlorine ions are attracted to the positive electrode. The match is wonderful, and the negativity and the positivity somehow enjoy the time spent with each other.


NaCl –> Na+ + Cl


Sodium chloride decomposes into sodium and chlorine ions


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.


Disposal: Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.


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Ammonia has been used by doctors, farmers, chemists, alchemists, weightlifters, and our families since Roman times. Doctors revive unconscious patients, farmers use it in fertilizer, alchemists tried to use it to make gold, weightlifters sniff it into their lungs to invigorate their respiratory system and clear their heads prior to lifting tremendous loads. At home, ammonia is used to clean up the ketchup you spilled on the floor and never cleaned up.


The ammonia molecule (NH3) is a colorless gas with a strong odor – it’s the smell of freshly cleaned floors and windows. Mom is not cleaning with straight ammonia (it’s gas at room temperature because it boils at -28oF, so the stuff she cleans with is actually ammonium hydroxide, a solution of ammonia and water).  Ammonia is found when plans and animals decompose, and it’s also in rainwater, volcanoes, your kidneys (to neutralize excess acid), in the ocean, some fertilizers, in  Jupiter’s lower cloud decks, and trace amounts are found in our own atmosphere (it’s lighter than air).


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Ammonia is a strong base – it combines with acids to form salts:


NH3 + HCl –> NH4Cl


But ammonia also can act as a weak acid. Remember, an acid is a proton donor, as in this reaction with lithium, where the ammonia molecule donated one hydrogen atom:


2 Li + 2 NH3 –> 2 LiNH2 + H2


In this experiment, we make a stink and then we see something that will make us go ooooooh… and aaaaw. How fun is that? But you need to follow the instructions carefully and perform your experiment safely. Promise?


Ammonia will be generated by the combination of ammonium chloride and sodium carbonate. The amount of ammonia generated in this experiment is not a large amount. However, you really should experience this particular stink.


Materials:


  • 3 test tubes and rack
  • sodium carbonate (MSDS)
  • ammonium chloride (MSDS)
  • copper sulfate (MSDS)
  • sodium hydrogen sulfate (NaHSO4) (MSDS) Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.
  • water
  • test tube stopper
  • measuring spoon
  • gloves, goggles

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


A chemical reaction is going to occur when the ammonium chloride, sodium chloride, and another chemical reaction is going to occur when the copper sulfate is added. These compounds are the reactants in our chemical reaction, and the blue liquid, CuCl (copper chloride), at the end of the experiment, will be our product. This experiment displays two types of reactions, a decomposition reaction when we combine ammonium chloride and sodium chloride, and a double replacement reaction when we add copper sulfate to the mixture.


C1000: Experiments 19-21


Download Student Worksheet & Exercises


When we combine ammonium chloride and sodium carbonate, ammonia will be produced. We will add copper sulfate to that mixture, producing two chemical compounds with totally different properties from those exhibited by the original chemicals.


Two chemical reactions will occur in this experiment:


(1)   When you add ammonium chloride and sodium chloride to the water, a decomposition reaction will occur that produces ammonia gas, carbon dioxide gas, and sodium chloride dissolved in water. It is identified as a decomposition reaction because the reactants breakdown into elements or simpler compounds.


NaHCO3 + 2NH4Cl –> NH3 + CO2 + NaCl + 2H2O


sodium carbonate + ammonium chloride –> ammonia + carbon dioxide + sodium chloride + water


(2)   The next reaction takes place when copper sulfate is added to the sodium chloride and water. The products of this reaction are sodium sulfate and copper chloride (the blue color). This reaction is identified as a double replacement reaction due to the fact that the two reactants break apart and recombine, the reactants trading parts, recombining to form two other different compounds with properties completely different than those of the reactants.


NaCl + CuSO4 –> NaSO4 + CuCl


sodium chloride + copper sulfate –> sodium sulfate + copper chloride


Big suggestion here: All chemical vapors are best experienced by “wafting”, a procedure that brings the vapor to you, instead of sticking your nose in the test tube, bringing you to the vapors. Please get in the habit of smelling properly. If ammonia vapors can bring unconscious people back to consciousness, you should probably make sure you are sniffing safely.


Reminder: Always wash your hands or gloves, and your chemistry tools, when switching from one chemical to another to avoid contamination that could affect the experiment adversely.


Store: Put all chemicals away in their proper places to keep them organized and ready to be used again. All tools should be put away as well, but make sure hat they have been cleaned and dried before storing them. A rule of thumb in chemistry is always wash something three times.


Disposal: Pour liquids down the drain using plenty of water. Throw solid waste into the outside garbage to prevent filling the house with bad smells.


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This experiment is for advanced students.


ACID!!! The word causes fear to creep in and get our attention.


BASIC!!! The word causes nothing to stir in most of us.


The truth is, a strong acid (pH 0-1) is dangerous, but a strong basic (pH 13-14) is just as dangerous. In this lab, we will get comfortable with the basics of bases and the acidity of acids along with how you can use both and tell the difference between them.


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Familiar acidic solutions:


  • pH 1: Stomach acid
  • pH 2: Lemon juice
  • pH 3: Vinegar
  • pH 4: Soda pop
  • pH 5: Rainwater (serious acid rain could have a pH of 2-4)
  • pH 6: Milk
  • pH 7: Distilled water
  • pH 8: Egg whites
  • pH 9: Baking soda
  • pH 10: Antacid
  • pH 11: Ammonia
  • pH 12: Limewater
  • pH 13: Drano
  • pH 14: Sodium hydroxide (NaOH)

Materials:


  • Lemon
  • Apple
  • Blue litmus paper
  • White vinegar
  • Clear glass cup
  • Tartaric acid (C4H6O6)
  • Measuring spoon
  • Measuring syringe
  • Water
  • Test tube rack
  • Test tube
  • Cool water
  • Sodium hydroxide (NaOH) (MSDS)
  • Dropper pipette
  • Calcium hydroxide (CaOH) (MSDS)
  • Erlenmeyer flask
  • Solid rubber stopper
  • Storage bottle
  • Stick-on label
  • Permanent marker

Acids usually taste sour and turn blue litmus paper red. There are exceptions. One exception to this is with apples. They contain malic acid. Malic acid does in fact taste sour by itself, but apples produce so much sugar that the sour taste of the acid is overpowered with sweetness. Making lemonade is a good example as well.


NaOH – Be very careful working with sodium hydroxide (NaOH). It isn’t an acid, so it shouldn’t be very harmful, right? WRONG! A strong base is just as dangerous as a strong acid. Please be careful when using them.


Don’t get confused and don’t forget what litmus paper indications mean. Acids turn blue litmus paper red, and bases turn red litmus paper blue. If you are testing a substance and the paper doesn’t change color, try the other type. The substance might not be neutral, but an acid or base that you used the wrong color litmus paper.


When testing with litmus paper, don’t dip the litmus paper into the chemical bottle. Use a clean dropper to transfer the chemical to the paper. Dipping into the chemical can and will, eventually, contaminate the chemical.


When shaking a liquid in a test tube or flask, put a solid rubber stopper on top. If you just start shaking from there, your stopper may fly across the room and scare your dog unnecessarily. The hot, or acidic, or basic contents of the container will find a place on the salad waiting to be served. The paramedics will be puzzled when they find the entire family, heads down, lettuce hanging from their mouths. With the stopper firmly inserted, wrap your hand around the container with your thumb over the stopper, pushing down to hold it in place while you shake.


After we finish the experiment, don’t discard the contents of the Erlenmeyer flask. It now contains limewater, a substance that we want to save for later experiments. Carefully pour the liquid into a storage bottle and discard the solids in the trash. Place a sticker on the bottle and/or use a permanent marker to label the bottle for future use. Keep the storage bottle out of direct sunlight when storing it.


We will explore for ourselves some of the properties of acids and bases. If we consider the acid-base theory discussed below, it will help us to further understand what we are experiencing in our lab.


C3000: Experiments 5-18


Download Student Worksheet & Exercises


Cleanup: We must clean everything thoroughly after we finish with the lab. After cleaning with soap and water, we need to rinse everything thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids can be washed down the drain, and solids put in the trash.


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This experiment is for advanced students.


Ever use soap? Sodium hydroxide (NaOH) is the main component in lye soap. NaOH is mixed with some type of fat (vegetable, pig, cow, etc).  Scent can be added for the ‘pretty’ factor and pumice or sand can be added for the manly “You’re coming off my hands and I’ll take no guff” factor. Lots of people still make their own soap and they enjoy doing it.


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One of the coolest uses for sodium hydroxide is in tissue digestion. By “tissue” we mean meat, bone, sinew…..meaning bodies! People who pick up dead animal (road kills) for the county dump their catch in barrels containing sodium hydroxide. The NaOH eats everything up and then the “sludge” is dumped in the landfill. They used NaOH to make them decompose. So this stuff is nasty and should never be touched with your bare hands!!


Materials:


  • Erlenmeyer flask
  • Alcohol burner
  • Lighter
  • Heating rod
  • Sodium carbonate (Na2CO3) (MSDS)
  • Calcium hydroxide (Ca(OH)2) (MSDS)
  • Measuring spoon
  • Water
  • Tripod stand
  • Wire screen
  • Chemistry stand
  • Test tube holder
  • Test tube rack
  • Test tube
  • Filter paper
  • Funnel
  • Stock bottle for NaOH storage (MSDS)

Don’t inhale any fumes from reactions or powder welling out of chemical containers, especially calcium hydroxide dust. We want to test our product to see if it is NaOH. It should turn red litmus blue.


We will perform a bunch of operations in this lab.


  1. Heating our calcium hydroxide / sodium carbonate mixture to create calcium carbonate and sodium hydroxide.
  2. Filter out the calcium carbonate to collect the sodium hydroxide.
  3. Test our sodium hydroxide product for the properties of NaOH.

C3000: Experiments 172-173


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


Ca (OH)2 +     Na2CO3 –>  2NaOH     +     CaCO3


Calcium hydroxide and sodium carbonate are combined in water and heated to produce sodium hydroxide and calcium carbonate


This is a double replacement reaction because the calcium ion and the sodium ion have swapped places


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids must be neutralized with vinegar, if a base, or baking soda, if an acid, before washing them down the drain. Before actually washing them down the drain check again with litmus paper to ensure that they have been neutralized. Solids are thrown in the trash.


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This experiment is for advanced students.


Potassium permanganate (KMnO4) in water turns an intense, deep, purple. It is important in the film industry for aging props and clothing to make them look much older than they are.


Also, artists use it in bone carving. People who carve antlers and bone use KMnO4 to darken the surface of the bone to make it look aged. They make the carving, soak it in potassium permanganate, then carve more, and repeat. The end result is a carving that has a light golden brown color. More dipping will darken the carving even more.


Potassium permanganate is going to undergo a chemical change with this activity. In this experiment, we will be able to witness several indicators of chemical change. Color changes, bubbles from gas generation, temperature change, and color disappearance are all indicators of chemical changes.


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Examples of chemical color changes we might be familiar with are autumn leaves changing color and a half eaten apple quickly turning brown.


Physical changes can mimic the indicators of chemical change, so we will need to always think through what we observe and then decide whether it is a physical or chemical change. Physical changes that mimic chemical changes can be color and temperature. The key is that physical changes are changes in state (solid, liquid, gas, sublimation) or changes in the condition of the material. In our pursuit of science knowledge, we will observe many physical and chemical changes. We need to be able to identify them accurately to really understand what is happening in an experiment.


Materials:


  • 3% Hydrogen peroxide (KMnO4) (MSDS)
  • Test tube rack
  • 2 test tubes
  • Potassium permanganate (KMnO4) (MSDS)
  • Sodium hydrogen sulfate (NaHSO4) (MSDS) Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.
  • Measuring syringe
  • Water
  • Measuring spoon
  • Solid rubber stopper

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


Always cap your chemicals after use and set them aside where they won’t get in the way. Your lab area should always be clear, clean, and uncluttered. Water and a fire extinguisher should be within arm’s reach. Always clean equipment before using any of it on another chemical.


Potassium permanganate is going to undergo a chemical reaction that will turn the deep violet or purple solution clear. It is a very cool experiment and looks like a lot of fun.


C3000: Experiment 102


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


KMnO4 + NaHSO4 + H2O2 = MnSO4 + O2 + NaOH + KOH


Potassium permanganate is added to sodium hydroxide, and then hydrogen peroxide is added and quickly capped.


MnSO4 + O2 + NaOH + KOH


The product of the reaction is manganese sulfate, oxygen, sodium hydroxide, and potassium hydroxide. The remaining chemicals are all clear, so the desired result is obtained.


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids can be washed down the drain


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This experiment is for advanced students.


How do you know if your brother is stealing your candy? Unwrap a wrapped hard candy that he likes a lot. Roll the candy around in the powdered food dye that matches the candy. (Push the powder into the candy so it “disappears”.) Re-wrap the candy. Set the candy in the place where it usually disappears from. Wait ten minutes after the candy disappears. Find your brother. He will be sporting a new color on his hands and mouth. Dye is hard to remove. It will have to be worn every day at school until it fades away as the skin cells slough off. The dye he now wears is in indicator that he has been taking your candy.


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Did you guess that this lab is about indicators? A reagent is chemical compound that creates a reaction in another substance; the product of that chemical reaction is an indicator of the presence, absence, or concentration of another substance.


Your brother’s situation is not a chemical reaction, but a reaction will be observed in his looks and his mood.


We are going to prepare copper sulfate and ammonium iron sulfate solutions and test them to see if our reagent, potassium hexacynoferrate II will cause chemical changes that indicate that copper is present in one, and iron is present in the other.


I’m sure your brother will stay far away from your candy from now on. I know this is obvious, but don’t eat anything in this lab or use it to coat candy… that was just an example to illustrate what an indicator is and how to use it.


Materials:


  • Erlenmeyer  flask
  • Water
  • Potassium hexacynoferrate II    K4Fe(CN)6 (MSDS)
  • Copper sulfate   CuSO4 (MSDS)
  • Measuring spoon
  • Solid rubber stopper
  • Test tube rack
  • 3 Test tubes
  • Measuring syringe
  • Small labeled container for NaOH
  • Dropper pipette
  • Ammonium iron sulfate   NH4Fe(SO4)2 (MSDS)
  • Sodium hydroxide   NaOH (MSDS)

We need to remember to only make as much Potassium hexacynoferrate II as we need. Label test tubes with contents information clearly visible. Always remember that when the term “reagent” is used in chemistry it is referring to an indicator chemical.


We will put together two solutions with metallic chemicals dissolved in water in each. Let’s pretend we have no idea if they are metallic or not. Many times as a chemist, when analyzing a customer’s of a production chemical, we are looking for metal in a solution as an indicator of something good or something bad. If one of the factory’s systems contains a corrosive liquid flowing through its veins, it would be good to know if some metal somewhere is corroding, being dissolved, by the fluid. Our tests could confirm a problem or set the boss’s mind to rest….and get us a big bonus if we save the day.


C3000: Experiments 260-264


Here’s what’s going on in this experiment:


In test tube #1: Copper sulfate solution into which we added Potassium hexacynoferrate II. A color change occurred (brown) and a precipitate fell out of the liquid to rest on the bottom of the test tube. This reaction was an indicator for the presence of metal.


In test tube #2: Ammonium iron sulfate solution into which we added Potassium hexacynoferrate II. A color change occurred (dark blue). This reaction was an indicator for the presence of metal.


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids, after neutralization, can be washed down the drain. Solids are thrown in the trash.


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This experiment is for advanced students.


Sparks flying off in all directions…that’s fun. In this lab, we will show how easy it is to produce those shooting sparks. In a sparkler you buy at the store, the filings used are either iron or aluminum.


The filings are placed in a mixture that, when dry, adheres to the metal rod or stick that is used in making the sparkler. The different colors are created by adding different powdered chemicals to the mixture before it dries. When they burn, we get red, blue, white, and green.


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Materials:


  • Card stock
  • Alcohol burner
  • Iron filings
  • Gloves

It’s tempting to use a handful of filings to produce a literal shower of sparks. The effect is actually better with small amounts. To accomplish anything with a large pile of filings would require you to blow REALLY hard to make a filing cloud that will combust well. A larger reaction means more sparks flying around. The amount of filings recommended in the lab is a safe amount. Increasing the amount used increases the danger. You could take an interesting, fun, and safe lab and transform it into something that burns the hair off your arms. Besides, burning hair doesn’t smell good.


Here’s what’s going on in this experiment:


Iron + Oxygen –> Iron Oxide


Iron and Oxygen are burned to produce Iron Oxide


This is the balanced chemical equation: 2Fe + O2 –> 2FeO


C3000: Experiment 54


Download Student Worksheet & Exercises


Handling iron filings is not dangerous. Minor things that can occur, such as: Iron filings can stain your skin gray; if there is a large filing in your container, rubbing your finger against it could give you a painful splinter.


Return unused filings to your container. Any surface these filings touch turns gray, so keep your filings corralled. Cleaning your work surface with a wet paper towel is the easiest way to clean up.


Discard any unburned iron powder that is coating the area around your alcohol burner into a trash container outside. It is not toxic, but still….don’t use chemicals or experiment residue as a snack. Never a good idea.


What is going on here? When you build a campfire at the campground, why doesn’t the grill spark and burn up? The grill is iron, the filings are iron, and there is always oxygen available in the air. What’s the deal here? Combustion needs two things, fuel and fire. Not enough of either and nothing will burn. But a woodstove is made up of a lot more iron by weight than that little scoop of filings. It has to do with surface area. Take an equal weight of solid iron and iron filings. Put a match to the solid iron and all it gets is hot. Blow the same weight of iron filings into the flame and POOF! The key is surface area. Surface area can affect the way a chemical reaction occurs, and in this case, whether or not it occurs at all.


To better understand the effect of surface area, eat some candy! Put a whole Lifesaver candy in your mouth. Suck, move your tongue all over it, swish it back and forth in your mouth. You are not allowed to bite or swallow it. How long does it take to completely dissolve? Do the same thing with another Lifesaver broken into pieces. Which dissolved faster? The same thing happens with the iron. The smaller the pieces, the easier it is for the iron to burn. When you blew iron filings into the air above the flame, you increased the surface area even more by increasing the air space between the particles. An increase in surface area always makes things happen faster. Granulated sugar dissolves faster than sugar cubes, and a piece of wood burns faster after you chop it into kindling. Pay attention and you will notice other situations where increasing surface area speeds up physical changes and chemical reaction times.


An additional experiment that you can try on your own is burning steel wool. Properly prepared ahead of time, steel wool will spark as it burns up. A great emergency fire starter is a 9V battery and steel wool. Fluff up the steel wool and touch a portion of it across the terminals of the battery. The steel wool will burn just like it did with a match.


Steel wool is just a ball of really long iron filings. If you fluff out the steel wool and light it, it burns easily. If you do try this, do it outside over the lawn or an area of dirt. At some point in the combustion you will want/need to drop the steel wool or get your fingers singed.


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This experiment is for advanced students.


In gas form, element #59 is deadly. However, when iodine is in  liquid form, it helps heal cuts and scrapes. The iodine molecule occurs in pairs, not as a single atom (many halogens do this, and it’s called a diatomic molecule). It’s hard to find iodine in nature, though it’s essential for staying healthy… too little iodine in the body takes a heavy toll on how well the brain operates.


A chunk of iodine is blackish-blue, and will sublimate (go from a solid straight to a gas, as seen in the photo here).  Iodine is the heaviest element needed by living things. Iodized salt is sodium chloride fortified with iodine to prevent people from not getting enough iodine in their daily diets.


Iodine is found in seaweed (kelp) and seafood as well as vegetables that are grown in dirt that has high iodine levels. People that live inland and do not eat fish often have lower iodine levels than their coastal, fish-eating neighbors. The trick is not to get too much or too little iodine in your diet, because the symptoms of deficiency and excess levels are quite similar.


Starch (like cornstarch) are used as an indicator for detecting iodine in chemistry experiments. When combined with iodine, starch forms a blue-black color in the solution. We’re going to do this and many other activities in this lab, because this experiment is actually several labs rolled into one. First, we have to make iodine, store it, and then we get to use it in several experiments. Are you ready?


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Materials:


  • Goggles
  • Gloves
  • Glass jar
  • Chemistry stand
  • Test tubes
  • Test tube holder
  • Measuring spoon
  • Corn starch peanut
  • Water cup
  • 90 degree bend glass tubing
  • One-hole rubber stopper
  • Paper towels
  • Stain-free work surface
  • Solid rubber stopper
  • Denatured alcohol
  • Dark brown glass storage bottle for iodine
  • Dropper pipettes
  • Alcohol burner
  • Lighter
  • Measuring syringe
  • Water
  • Potassium iodide KI (MSDS)
  • Potassium permanganate KMnO4 (MSDS)
  • Sodium hydrogen sulfate NaHSO4 (MSDS) AKA: Sodium Bisulfate Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


Remember that iodine is toxic paper and harmful to the environment.
Safely shake test tube to homogenize chemicals using a solid rubber stopper and dispose of in the outside trash.


NOTE: Heat slowly and carefully. You don’t want your test tube in the flame. The end of the glass tubing should not extend into the alcohol. From time to time, touch the end of the glass tubing to the alcohol to rinse iodine from the tube into the alcohol, but the glass tubing shouldn’t reside in the alcohol. Conduct this experiment outdoors or in an extremely well ventilated area inside the house.


Follow cleanup instructions carefully for safety. These are very toxic substances we are working with.

As heating progresses, purple gas will form in the upper test tube. A brown color will begin to form in the alcohol. Heat until purple smoke disappears from the upper test tube.


C3000: Experiments 139-149


Here’s what’s going on in this experiment:


2KI + KMnO4 + NaSO4 + H2O–> I2 + MnO2 + KOH +KIO3 + Na2SO4


Potassium iodide and potassium permanganate and sodium sulfate and water are heated to produce free iodine gas and magnesium oxide and potassium hydroxide and potassium iodide and sodium sulfate.


All this to produce the iodine we need for the next several experiments.


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids need to be filtered through a paper towel and washed down the drain with plenty of water. Solids are thrown in the outside trash.


Going Further

*Save all solutions you make in these experiments. You will use them in the other experiments.


Testing Iodine solution

After the drops of iodine are in the test tube with water, observe. Any solid particles in the test tube prove that our iodine is not soluble in water.


Addition with Iodine

Using the solution from the above experiment, adding KI will dissolve all the solids that were observed. Why did the solids disappear? Well, nothing dramatic was seen, but an addition compound was created.


I2 + KI  –>  KI I2


Sodium Thiosulfate

Sodium thiosulfate (Na2S2O3) solution is pipette drop by drop to above solution until it turns clear. The reaction that takes place turns our solution into sodium hypoiodite (NaOI)


Packing Peanut

We fill a glass jar with water and 10 drops of iodine and mix well. The water will be a pale brown. Dissolve a corn starch peanut in water. When we add starch solution to the iodine and water, the water turns clear, then blue. We have just created iodine starch!


Colorless Iodine

Sodium thiosulfate solution from an experiment above. Put a few droppers of this solution into the iodine starch and stir. Colorless! We have a colorless iodine solution….very cool!


Iodine and Heat

To set this one up, dropper one drop of iodine solution into a test tube half-filled with water. Then we regain our bright blue color by adding our starch solution to the iodine water.


When we add heat, The solution turns clear! But, we’re not done. The test tube goes into a half full jar of cool water. The solution in the test tube is turning blue. If you keep doing these actions over and over again, you will keep getting the same results.


Did you notice something? The reaction is ________. Think, now.
(Psst! It’s reversible!)


Colorless Iodine Without Heat

In this experiment we use alcohol to achieve a clear solution. We pour some iodine starch solution into some alcohol and the solution turns clear. The alcohol removed the iodine from the solution.


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This experiment is for advanced students.


Zinc and Hydrogen are important elements for all of us. Zinc (Zn) metal is element #30 on the periodic table. Lack of zinc in our diets will delay growth of our bodies and can kill.


Hydrogen gas (H) is element #1 on the periodic table. Hydrogen was discovered in the 1500s. In a pure state, hydrogen combustion (in small quantities) is interesting. In large amounts, mixed with oxygen, the explosion can be devastating.


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We are going to perform an experiment that generates a small amount of hydrogen gas, with a correspondingly small explosion. Hydrogen is violently flammable in air, but by itself….not so much. Hydrogen is lighter than air, so has been used in airships, or blimps. The Hindenburg, a German airship filled with hydrogen, burned up quickly on May 6, 1937 while tied to a mooring mast.


Currently, hydrogen is being thought of as the “fuel of the future” for our cars and other vehicles. Most the Earth’s our hydrogen is contained in water (H2O). Most of the experimentation has been in producing hydrogen through electrolysis. That proves very expensive to produce and transport. Until a cheaper alternative appears, hydrogen (H2) is not a practical alternative.


Scientists are lately giving a lot of attention to a process that will produce hydrogen cheaply and easily.  That method is to heat zinc powder in the presence of air (oxygen). It can be achieved at low temperatures, little cost, and little danger – perfect for a hydrogen fuel cell in our car. Don’t go filling your tank with it right away, though. Engineers still need to work some bugs out. It will happen soon, so be patient. (And remember, you saw it first in your chemistry set!)


Materials:


  • Gloves
  • Goggles
  • Chemistry stand
  • Zinc (Zn) powder (MSDS)
  • Measuring spoon
  • 4 test tubes
  • Test tube holder
  • Alcohol burner
  • Lighter
  • One-hole rubber stopper
  • Rubber tubing
  • 900 bend glass tubing
  • Water
  • Measuring syringe
  • Stirring rod
  • Clear pan

Important! Dispose of the Zinc (Zn) left in the test tube in the outside trash. Accidentally ingesting (and it should only be accidental) of Zinc (Zn) or Zinc Chloride (ZnCl), will harm you or animals. It will not be one of your best days. Call 911 if this happens.


After you have finished your experiment, be careful of the hot test tube containing the zinc compound. The test tube is very hot, and there will be a difference in pressure between the water tank and the test tube. Because the test tube has been heated, the pressure is less than atmospheric pressure.


As it cools, the water in the tank, which is at atmospheric pressure (the pressure of the air in the room) is higher than in the test tube. The test tube’s low pressure is looking to suck something, anything, up the glass tube. The water, sitting there at normal air pressure, notices the need. Water climbs up the tube  in response to the test tube’s request.


At the conclusion of the experiment, with the heat off, the test tube starts to cool and water then donates some stuff to equalize the pressure. If allowed to , that cool water hits that hot zinc, or hot test tube, and the test tube could explode and the zinc could quickly react, blowing out the stopper and spewing hot zinc all over you.


Here is the safety information for the products in this chemical reaction:


You first put zinc powder and water together in the end of the horizontally held test tube. But why place a pile of, dry zinc, laying in the test tube near the wet zinc? We want to create a chemical reaction with zinc and water. Wet zinc powder in the end of the test tube allows the dry zinc to come in contact with water when they are both heated without the powder actually getting wet. This way the reaction occurs faster and more efficiently. We don’t have to wait any longer than necessary this way.


C3000: Experiments 67-69


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


In this experiment we are causing a single replacement reaction to occur between zinc powder and water. In a replacement reaction, a compound breaks down into its elemental parts in the first stage of the chemical reaction. A new compound is created as the elements search about for something to bond with to satisfy their needs to gain or give up electrons.


Zn + H2O –> ZnO + H2


Zinc powder reacts with water under the influence of heat to become zinc oxide and hydrogen gas. The new compound is called zinc oxide (ZnO).


Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three more times. Dry them before putting them away.


Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.


Disposal: Dispose of all solid waste in the outside garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.


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WARNING!! THIS EXPERIMENT IS PARTICULARLY DANGEROUS!! (No kidding.) This experiment is for advanced students.


We’ve created a video that shows you how to safely do this experiment, although if you’re nervous about doing this one, just watch the video and skip the actual experiment.


Bromine is a particularly nasty chemical, so be sure to very carefully follow the steps we’ve outlined in the video. You MUST do this experiment outdoors. We’ll be making a tiny amount to show how the chemical reactions involving bromine work.


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Isn’t it interesting how many ways we can use the same techniques and, by just changing a few chemicals, we can learn about so many different chemical reactions? This lab is similar in technique to the Generating Hydrochloric Acid lab. Using the same techniques, we will produce hydrogen bromide.


Hydrogen bromide (HBr) was used as a sedative in the late 1800s and early 1900s. Once they found out how poisonous it really was  (after enough people became blind and/or dead), someone had the wonderful idea that maybe we shouldn’t use it anymore. It was also used to control epilepsy until the substitute Phenobarbital came on the scene in 1911. HBr is still used to treat epilepsy in dogs. In cats HBr causes inflammation of the lungs and makes for a very unhappy cat.


Materials:


  • Alcohol burner
  • Lighter
  • Wire screen
  • Tripod stand
  • Glass jar
  • Rubber tubing
  • 900 Glass tubing
  • One-hole rubber stopper
  • Chemistry stand
  • Test tube holder
  • Test tube
  • Potassium bromide (KBr) (MSDS)
  • Sodium hydrogen sulfate (NaHSO4) (MSDS) Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.
  • Burette
  • Water
  • Sodium carbonate (Na2CO3) (MSDS)
  • Silver nitrate (AgNO3) (MSDS)

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


Maintain good and proper lab techniques. We are working with some nasty stuff in this lab. We need to perform this lab outdoors if possible, or indoors with lots of ventilation. The reaction advances in stages:


  • Bubbles in the burette tell us the reaction is occurring.
  • Brown streaks will appear in the water contained in the glass jar as gas collects there.
  • Brown vapor will begin to appear in the test tube. When the reaction is complete, the test tube will contain lots of brown vapor.

After we produce HBr, we will perform a number of tests to see if it is an acid or a base.


  1. Test contents of test tube with blue litmus paper. Red color change indicates an acid.
  2. Add baking soda to the HBr. Bubbles and the solution turning white. HBr is an acid in this test because it is obviously reacting with a base.
  3. If a magnesium strip placed in the HBr corrodes, or starts to dissolve, then HBr is an acid.
  4. With the addition of silver nitrate to the HBr, if a white cloudiness occurs and crystals form in the bottom of the test tube, then HBr is an acid.

C3000: Experiments 134-138


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


KBr    +    NaHSO4 –>    HBr    +    KNaSO4


Potassium bromide and sodium hydrogen sulfate, when heated, produce hydrogen bromide and potassium sodium sulfate.


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Liquids can be washed down the drain. Solids are thrown in the trash.


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WARNING!! THIS EXPERIMENT IS PARTICULARLY DANGEROUS!! (No kidding.) This experiment is for advanced students.


We’ve created a video that shows you how to safely do this experiment, although if you’re nervous about doing this one, just watch the video and skip the actual experiment.


The gas you generate with this experiment is lethal in large doses, so you MUST do this experiment outdoors.  We’ll be making a tiny amount to show how the chemical reactions of chlorine and hydrogen work.


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Hydrochloric acid is a strong acid. It is highly corrosive, which means that this acid will destroy or irreversibly damage another substance it comes in contact with. Simple terms….it is pretty nasty, so take special care when working with or around it.


HCl is used in processing leather, cleaning products, and in the food industry. We are most familiar with HCl in the form of Gastric Acid. HCl is in gastric acid and is one of the main ingredients in our stomach to aid in digestion of our food. In our lab we will produce hydrogen chlorine gas and add water to turn change it into hydrochloric acid.


Materials:


  • Glass jar
  • 900 bend glass tubing
  • One-hole rubber stopper
  • Chemistry stand
  • Wire mesh
  • 2 Test tubes
  • Test tube clamp
  • Alcohol burner
  • Lighter
  • Tripod stand
  • Sodium hydrogen sulfate (MSDS) Sodium hydrogen sulfate is very toxic. Respect it, handle it carefully and responsibly. Do not take it for granted.
  • Salt
  • One-hole cork
  • Medicine dropper
  • Water
  • Solid rubber stopper

NOTE: Be very careful when handling the sodium hydrogen sulfate – it’s highly corrosive and dangerous when wet.  Handle this chemical only with gloves, and be sure to read over the MSDS before using.


Perform this experiment outdoors. If that is not a possibility, and you must do it inside, open doors and windows to provide lots of ventilation. Hydrogen chlorine gas inhalation can be fatal, but we are only producing a very small amount.


There are many steps in this lab, so go slow and steady. Read the lab over several times so you are sure what is going on and what is happening next.


When we shake the sodium hydrogen sulfate and the salt together in a stoppered test tube, we are trying to produce a heterogeneous mixture. Heterogeneous is a scientific word that means substance are mixed all together to be as one. A sample taken from one spot in the mixture should be the same as a sample taken from any other spot in the mixture.


At some point in this lab, we need to point the test tube containing the reaction slightly down. This is so the hydrogen chlorine gas can flow downhill. The gas is denser than air, so it will sink to the bottom of anything air filled…..like a room or a test tube.


Hydrogen chloride gas is poisonous – DO NOT INHALE!


When the medicine dropper / cork tool is placed in the water, water will be sucked up into the test tube. The water combines with the hydrogen chlorine gas to create hydrochloric acid.


A double replacement chemical reaction will take place in this experiment. A free hydrogen ion (+) and a free sodium ion (+) will be produced. Because their charges are alike, they cannot bond, but they can take each other’s place. The spots they each left are negatively charged after the hydrogen and sodium have departed. Opposites attract, and they reorganize into a double replacement reaction.


C3000: Experiment 112


Download Student Worksheet & Exercises


Here’s what’s going on in this experiment:


NaCl  +  NaHSO4 –>  HCl  +  Na2SO4


Salt is combined with sodium hydrogen sulfate and heated to produce hydrochloric acid and sodium sulfate


Cleanup: We are going to clean everything thoroughly after we finish the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.


Storage: Place cleaned tools and glassware in their respective storage places.


Disposal: Our HCl needs to be neutralized before disposal. Put a bit of baking soda into the test tube. The contents should bubble as the neutralization is taking place. After neutralization, the liquid is safe, and can be washed down the drain. Solids are thrown in the trash.


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In this unit, you will learn how to build your own home chemistry lab safely under the direction of professionals. We’ll show you how to do real chemistry experiments, provide chemical storage information, give guidelines on proper chemical disposal when you’re finished, highlight lab tips and tricks, and warn you about things to watch out for. This is real chemistry for real kids.


This video picks up where the intermediate chemistry video leaves off so you’ll want to be sure you have completed that one first. The C3000 contains three trays, the first of which is the C1000 (which is covered in the intermediate chemistry lesson). So if you’ve completed the first part and are ready for more, here we go!


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NOTE:For the Alcohol Burner Wick: Tape tightly around one end, making the end small and tapered. You can also put glue (white glue or rubber cement work great) into the fibers at one end. As the glue hardens, form the end into a smaller and tapered end. It will slide through easily, and cut the end off and your ready to go.


How do I use this information? You have two options, depending on your comfort level and ultimate educational goals. You can just watch the videos and talk about what’s going on with your child, or you can watch the videos and then perform the experiment with your child.


This unit includes the instructional videos for Chemistry, and is meant to be used in conjunction with the experiments in the Thames and Cosmos C1000 and/orC3000 chemistry lab kits.  The manual included in the C1000 and 3000 has complete safety information and many more experiments for you to complete after you finish this unit.


All experiments presented here at AT YOUR OWN RISK. You are fully responsible for your own safety and those around you. (No building nuclear reactors in your garage.)


To put it simply, don’t eat anything in your chemistry lab, keep children and pets away from your lab, lock up your chemicals safely, learn how to store your chemicals safely, and don’t create large quantities of anything explosive, corrosive, or toxic. Always wear safety equipment and do your experiments in a spot what has plenty of air for ventilation, water and a drain, and a phone.


In all seriousness, be safe, have fun, play with the kids, and if you run across anything that boggles the mind, let us know and we’ll try to help you out.


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In this unit, you will learn how to build your own home chemistry lab safely under the direction of professionals. We’ll show you how to do real chemistry experiments, provide chemical storage information, give guidelines on proper chemical disposal when you’re finished, highlight lab tips and tricks, and warn you about things to watch out for. This is real chemistry for real kids.


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How do I use this information? You have two options, depending on your comfort level and ultimate educational goals. You can just watch the videos and talk about what’s going on with your child, or you can watch the videos and then perform the experiment with your child.


This unit includes the instructional videos for Chemistry, and is meant to be used in conjunction with the experiments in the Thames and Kosmos C1000 and/orC3000 chemistry lab kits.  The manual included in the C1000 and 3000 has complete safety information and many more experiments for you to complete after you finish this unit.


All experiments presented here at AT YOUR OWN RISK. You are fully responsible for your own safety and those around you. (No building nuclear reactors in your garage.)


To put it simply, don’t eat anything in your chemistry lab, keep children and pets away from your lab, lock up your chemicals safely, learn how to store your chemicals safely, and don’t create large quantities of anything explosive, corrosive, or toxic. Always wear safety equipment and do your experiments in a spot what has plenty of air for ventilation, water and a drain, and a phone.


In all seriousness, be safe, have fun, play with the kids, and if you run across anything that boggles the mind, let us know and we’ll try to help you out.


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If you’re struggling to untangle the confusion about significant digits, then this is the video you’ll want to watch. Get a calculator, sheet of paper, and a pencil and get ready to become a super-genius on sig figs!



This Lesson is for advanced students. Most people who learn about electronics start by studying the theory of how electric current flows through wires and other stuff that conducts electricity, called conductors. Unfortunately this stuff is BORING! I mean, I can’t stand it myself sometimes. So, we’re going to start with what I call “Lego brick” electronics.


You’re going to start by building cool things, then learn what each part of the circuit does, but not go into the minute details. You’ll learn how to build circuits out of electronic “bricks” like you can build something out of Lego bricks. You don’t need to design your own Lego bricks, but just focus on using them. Same thing here – you’ll learn how to put pieces together to build circuits. Our pieces are electronic components. Things like transistors, resistors, integrated circuits (chips), capacitors and lots more.


Although you can’t see electricity, you can certainly detect its effects – a buzzer sounding, a light flashing, a motor turning… all of these happen because of electricity. Which is why electricity experiments are among the most frustrating. You can’t always tell where the problem is in a circuit that refuses to work right.
We’re going to outline the different electronic components (resistors, capacitors, diodes, transistors, etc) so you get a better feel for how to use them in a circuit. While we’re not going to spend time on why each of these parts work (which is a topic best reserved for college courses), we are going to tackle how to use them to get your circuit to do what you want. The steps to building several different electronics projects are outlined very carefully so you can really understand this incredible micro-world.


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Electronics are used everywhere these days. Of course, we see them in TV’s and stereos, computers, cell phones and iPods. But they’re also a part of car keys and even mailing labels on boxes.


They’re used to explore the surface of mars in space probes and give sight to blind people. All these things use transistors, resistors, chips and more – just what we’ll be talking about in this unit. So, let’s get started.


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Note: Because there is so much overlap between the lessons in this unit, I’ve combined all the questions from Lessons 1-3 and put them all in one place – right here on this page.


Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.


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  1. Name two different types of power supplies that you can use.
  2. If I have a 24 volt light bulb that uses 3 amps, what would happen if I hooked it up to a 1-amp power supply? 1000-amp power supply?
  3. What does a transformer do?
  4. I need a 5.6k-ohm resistor. What does the resistor color code look like?
  5. I need a 2k resistor, but I only have 1k resistors left in my bin. How do I connect them together to make a 2k resistor?
  6. Why bother using a capacitor in a circuit?
  7. I need a 400mf capacitor, but only have 200mf capacitors in my bin. How do I make a 400mf capacitor?
  8. Give examples of where you’d find AC and DC current in everyday life.
  9. What’s a diode and how do you know which way the electricity flows?
  10. What the difference between a microprocessor and microcontroller?
  11. What’s an IC?
  12. Can I substitute one transistor for another?

Need answers?

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Note: Because there is so much overlap between the lessons, I’ve combined the questions and put them all in one place – right here on this page.


Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.


Answers:
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  1. D-cell battery, AC wall adapter.
  2. 1-amp power supply wouldn’t light it up (and may damage the power supply), and the 1000-amp power supply would work just fine.
  3. A transformer is a component that trades volts for amps and vice-versa.  If I put 100 volts at 1 amp into a transformer, it might put out 10 volts at 10 amps.
  4. green-glue-red-gold
  5. Connect the resistors together in series.
  6. Capacitors are used for lots of different things.  They can be part of a “filter” circuit that removes unwanted electrical “blips” or signals.  For example, radios use capacitors.  You see, a radio initially doesn’t receive just one FM radio station.  No, it receives ALL the stations in your area at once.  Then, it has a filter circuit using capacitors to filter out all of the stations except the one that you have the radio tuned to.  Capacitors are also used to let AC current pass through them, but not DC.
  7. Connect the capacitors together in parallel.
  8. AC comes from your wall outlet and DC comes from a battery.
  9. A diode is like a one-way valve for electricity.  It lets current go through it one way, but not the other.  They have two leads, called the anode and the cathode.
  10. A common type of programmable chip is called a microprocessor.  These are the “brain” of a typical home computer.  A cousin of the microprocessor is the microcontroller.  A microcontroller is like a whole computer on a chip.
  11. An integrated circuit, sometimes called an “IC” or a “chip” (as in “computer chip”) is a complete circuit that has been miniaturized and put into a small plastic block with wires coming out of it.
  12. Not usually. In our breadboard circuits, however, you may substitute the NPN 2N2222A for a 2N3904. You may also substitute the PNP 2N4403 for a 2N3906. In most cases, the packaging on the outside makes it seem like you can swap one for another, but what’s inside is radically different. (Some that you’ll find aren’t even transistors, but only look like it!)

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This project is for advanced students.


This is two projects in one.  No one starts out soldering well (I know I didn’t).  So, we’re going to start out by just practicing soldering parts onto a PCB that doesn’t do anything.  No point in making mistakes on a real project and possibly ruining it.


Once you have the hang of soldering, we’ll  make a working siren.  Just follow along with the steps in the video.  By the way, the siren circuit isn’t that different from the Audible Light Probe.  It makes sound in a similar way, and is just wired to make different frequencies take turns by charging capacitors at different rates.


To make this project, you’ll need to get a Police Siren Kit. You’ll also need a soldering iron with a stand and some basic tools (scissors, hot glue gun, drill, wire strippers, pliers, screwdriver). (Need a recommendation for a soldering iron? Click here.)


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There are TWO versions of the Police Siren since the previous supplier went out of business! If you’ve purchased a science program from us, you’ll want to match up the one included in the package with the right video, because you can have either one, depending on how recently you purchased your program from us. If you’re wanting to purchase the siren separately (not from us), there’s an order link above, and you’ll want to watch the second set of videos near the bottom of this page.


Older Version of the Police Siren:


This is the Old Version that comes with TWO boards inside the package along with a booklet. The two videos below are for this one.


In the video below, you will learn how to solder:



And now build the project:



New Version of the Police Siren:


This is the NEW version that has only ONE board in the package. You can purchase the Police Siren directly from Jameco here. (Part Number: 2161617). The practice board and the siren are both in the same board. There are three videos for the new board. The first one introduces you to soldering, the second practices building the components, and the third finishes the siren project.



This video below shows you step by step how to build the sample board…



This video below shows you how to build the siren itself.



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fm-xmitterThis project is for advanced students. Make sure you’ve completed the Police Siren project first!


This is a really cool one.  You’re actually going to build a miniature radio station.  You can broadcast your voice or music to a regular FM radio.  It just has a very short range (about 100 feet, or 30 meters).


It’s just a bit more complicated than the siren, and it will need some “tuning” when you’re done with it.  Take your time with this one and have fun.


To make this project, you’ll need the Wireless FM Transmitter kit, your soldering equipment, and basic tools (pliers, wire strippers, scissors, etc.)


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There are two versions of this kit: Version 1 & Version 2. No matter which version you have, start watching the top video. For Version 2 kit owners, when it comes time to start building the kit, you’ll find complete building instructions on the lower video. Return to the top video for tuning and troubleshooting instructions.



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dooralarmThis project is for advanced students. Make sure you’ve completed the Police Siren project first!


This is my favorite burglar alarm because it’s innocent-looking, hair-triggered, and completely obnoxious. Here’s what happens: after you build this circuit, you hang the wire loop around a metal doorknob, add the battery, and stand back. When an unsuspecting thief comes into your room, the alarm sounds as soon as they touch the other side of the door knob… and presto! You caught your burglar.


This circuit uses an IC (integrated circuit) called the LM324, which is a quad op-amp (operational amplifier), which produces a voltage that many times larger than the voltage difference between the inputs.  Created in 1972, these low-power op-amps are actually four op-amps packaged into one. Although they are commonplace today in many electronic devices, they first started out in the 1940s as vacuum-tube devices at Bell Labs.


Are you ready to build a super-cool burglar alarm? To make this project, you’ll need to Door Knob Touch Alarm Kit, soldering equipment, and basic tools (scissors, hot glue gun, drill, wire strippers, pliers, screwdriver). (Don’t know how to solder yet? Click here for a lesson!)


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rollingclockThis project is for advanced students. Make sure you’ve completed the Police Siren project first!


This is a really cool project, because it uses a microcontroller chip.  This is a whole computer on a chip.  The chip already has software loaded on it.  It’s programmed to do just one thing: Keep time and make a clock go.  A new component in this circuit is a crystal.  This is the silver metal thing.  It has a piece of quartz crystal in it.  What’s cool about it is that if you apply voltage to it, it vibrates at a very precise frequency, which makes it ideal for keeping accurate time.  These are used in virtually every electronic clock you can find (and anything else that requires precise timing).


While this IC chip is programmed to be a clock, the same chip could be re-programmed to scroll a text message across the display.  If you really get into these types of circuits, you can learn to program microcontroller chips yourself from a regular computer (just like you do with a flash drive).  So, remember, someone programmed this chip to be a clock, but all it really does is take inputs (electrical signals going in from things like the buttons and crystal), “process” them, and then create outputs (light up the LEDs in a certain pattern) based on its calculations.


To make this project, check the shopping list for Unit 14.


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Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.


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1. What is thermal energy?


2. What does temperature measure?


3. What are the three different scales used to measure temperature?


4. What is absolute zero?


5. If something is hot, what are its molecules doing?


6. In our “Spread It Around” experiment why did the food coloring spread out faster in the hot bowl than in the cold bowl?


7. In which parts of your body do you have your thermal energy antenna?


8. What are the four states of matter (ignoring BEC)?


9. Which states have no bonds between the molecules?


10. Which state has bonds that hold the molecules in a tight matrix?


11. As the temperature increases, what happens to the bonds that allow a substance to go from solid to liquid?


12. What happens to the bonds as a substance reaches its boiling point?


13. What happens to the bonds as a substance reaches its freezing point?


Need answers?


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Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.


Answers:
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1. Thermal energy is basically the energy of the molecules moving inside something. The faster the molecules are moving the more thermal energy that something has. The slower they are moving the less thermal energy that something has.


2. Temperature measures thermal energy. In other words, temperature measures the amount that the molecules are moving. Thermometers are speedometers for molecules.


3. Fahrenheit, Celsius, and Kelvin.


4. Absolute zero is a theoretical temperature where molecules and atoms stop moving. This temperature has never been reached in the laboratory but they have come close.


5. Its molecules are moving very quickly.


6. In the hot bowl, the molecules are moving very fast. Since they are moving quickly, they bump into the food coloring molecules more and harder spreading them out faster than in the cold water.


7. Skin.


8. Solid, liquid, gas, plasma


9. Gases and plasma


10. Solid


11. The bonds are forced to stretch and loosen up since the molecules are moving at greater speeds.


12. As a substance reaches its boiling point it changes from a liquid to a gas. As this happens the bonds that are holding the molecules together break allowing the molecules to wander off on their own as a gas.


13. As a substance reaches its freezing point it turns from a liquid to a solid. The bonds tighten up, pulling the molecules into a matrix and forming a nice solid substance.


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Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.


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1. What is heat?


2. Does heat flow from higher to lower temperature, from lower to higher temperature or does it matter?


3. When I first turn on the shower the shower curtain keeps blowing into my legs. Is this an example of conduction, convection or radiation?


4. When I bite into a pizza, the heat is transferred painfully to the roof of my mouth. Is this an example of convection, conduction or radiation?


5. Someone sits a little too close to me on a bus and I can feel the heat coming off of them. Is this an example of convection, conduction or radiation?


6. My daughter holds my hand as we walk across the street. I can feel heat coming from her hand to mine. Is this an example of convection, conduction or radiation?


7. It’s a hot sunny day outside. Am I better off wearing a dark shirt or a light shirt if I want to stay cool?


8. An object’s temperature always drops when it loses heat. True or false?


9. What happens to molecules as they change from one state to another?


10. When objects evaporate do they absorb heat or release heat?


11. Why do we sweat when we’re hot?


12. Why doesn’t temperature change when things are changing state?


13. What is heat capacity?


14. Which would cool down faster, a bottle of maple syrup or a teaspoon of maple syrup?


15. Owww!! I just burned my mouth on a piece of pizza! The strange thing is the crust is just warm. What happened?


16. When I eat at a fast food restaurant I always eat my fries before the burger since the fries get cold so much faster. Which has a higher heat capacity, the fries or the burger?


17. Why do I fill a hot water bottle with hot water and not just hot air?


Need answers?


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Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


Here’s printer-friendly versions of the exercises and answers for you to print out: Simply click here for printable questions and answers.


Answers:
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1. Heat is the movement of thermal energy from one object to another.


2. Heat can only flow from a higher temperature object to a lower temperature object.


3. Convection. The heat from the hot water in the shower heats up the air in the shower. The heated air rises. As the heated air rises, it creates a convection current. Which draws air into the shower and blows the shower curtain into my legs. Many of the winds on the Earth are caused by hot air rising and cold air sinking.


4. This is conduction. The fast moving molecules of the pizza bombard my poor mouth molecules. This, in turn, creates sound energy as I scream “OUCH!”.


5. This is radiation. Humans can transfer heat by radiation. The fellow sitting next to me was giving off infra-red radiation.


6. This time it’s primarily conduction. The molecules in her little hand are vibrating quickly and causing my molecules to vibrate quicker as well. There is probably some radiation going on as well, but since our hands are touching her molecules can directly affect my molecules.


7. A light colored shirt reflects more infra-red radiation so I’ll stay cooler.


8. False.


9. The “bonds” between molecules change. They can either tighten up or loosen up depending on whether the energy is increasing or decreasing.


10. They absorb heat.


11. The sweat absorbs excess heat from the body as it evaporates and cools us off.


12. The energy that’s entering the object is being used to change the bonds between the molecules. The molecules have reached their “speed limit”. They can’t go any faster or slower without changing state.


13. Heat capacity is how much heat an object can absorb before its temperature increases.


14. The teaspoon. The smaller the amount the less heat capacity it has.


15. The cheese has a much higher heat capacity then the crust. So the cheese stays hot much longer.


16. The burger holds onto its heat longer then the fries. The burger has a higher heat capacity.


17. Water has a higher heat capacity so it cools much more slowly than air. A hot air bottle will be cool in a matter of seconds.  Hot water will take many minutes to cool down.


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If you’ve ever had a shot, you know how cold your arm feels when the nurse swipes it with a pad of alcohol. What happened there? Well, alcohol is a liquid with a fairly low boiling point. In other words, it goes from liquid to gas at a fairly low temperature. The heat from your body is more then enough to make the alcohol evaporate.


As the alcohol went from liquid to gas it sucked heat out of your body. For things to evaporate, they must suck in heat from their surroundings to change state. As the alcohol evaporated you felt cold where the alcohol was. This is because the alcohol was sucking the heat energy out of that part of your body (heat was being transferred by conduction) and causing that part of your body to decrease in temperature.


As things condense (go from gas to liquid state) the opposite happens. Things release heat as they change to a liquid state. The water gas that condenses on your mirror actually increases the temperature of that mirror. This is why steam can be quite dangerous. Not only is it hot to begin with, but if it condenses on your skin it releases even more heat which can give you severe burns. Objects absorb heat when they melt and evaporate/boil. Objects release heat when they freeze and condense.


Do you remember when I said that heat and temperature are two different things? Heat is energy – it is thermal energy. It can be transferred from one object to another by conduction, convection, and radiation. We’re now going to explore heat capacity and specific heat. Here’s what you do:


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You Need:


  • Balloon
  • Water
  • Matches, candle, and adult help
  • Sink


Download Student Worksheet & Exercises


1. Put the balloon under the faucet and fill the balloon with some water.


2. Now blow up the balloon and tie it, leaving the water in the balloon. You should have an inflated balloon with a tablespoon or two of water at the bottom of it.


3. Carefully light the match or candle and hold it under the part of the balloon where there is water.


4. Feel free to hold it there for a couple of seconds. You might want to do this over a sink or outside just in case!


So why didn’t the balloon pop? The water absorbed the heat! The water actually absorbed the heat coming from the match so that the rubber of the balloon couldn’t heat up enough to melt and pop the balloon. Water is very good at absorbing heat without increasing in temperature which is why it is used in car radiators and nuclear power plants. Whenever someone wants to keep something from getting too hot, they will often use water to absorb the heat.


Think of a dry sponge. Now imagine putting that sponge under a slowly running faucet. The sponge would continue to fill with water until it reached a certain point and then water started to drip from it. You could say that the sponge had a water capacity. It could hold so much water before it couldn’t hold any more and the water started dripping out. Heat capacity is similar. Heat capacity is how much heat an object can absorb before it increases in temperature. This is also referred to as specific heat. Specific heat is how much heat energy a mass of a material must absorb before it increases 1°C.


Exercises Answer the questions below:


  1. What is specific heat?
    1. The specific amount of heat any object can hold
    2. The amount of energy required to raise the temperature of an object by 1 degree Celsius.
    3. The type of heat energy an object emits
    4. The speed of a compound’s molecules at room temperature
  2. Name three ways thermal energy can be transferred from one object to another:
  3. At what point does the balloon pop?
  4. True or False: Water is poor at absorbing heat energy.
    1. True
    2. False

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Every time I’m served a hot bowl of soup or a cup of coffee with cream I love to sit and watch the convection currents. You may look a little silly staring at your soup but give it a try sometime!


Convection is a little more difficult to understand than conduction. Heat is transferred by convection by moving currents of a gas or a liquid. Hot air rises and cold air sinks. It turns out, that hot liquid rises and cold liquid sinks as well.


Room heaters generally work by convection. The heater heats up the air next to it which makes the air rise. As the air rises it pulls more air in to take its place which then heats up that air and makes it rise as well. As the air get close to the ceiling it may cool. The cooler air sinks to the ground and gets pulled back near the heat source. There it heats up again and rises back up.


This movement of heating and cooling air is convection and it can eventually heat an entire room or a pot of soup. This experiment should allow you to see convection currents.


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You need:


  • A pot
  • A stove with adult help
  • Pepper
  • Ice cubes
  • Food Coloring (optional)


1. Fill the pot about half way with water.


2. Put about a teaspoon of pepper into the water.


3. Put the pot on the stove and turn on the stove (be careful please).


4. Watch as the water increases in temperature. You should see the pepper moving. The pepper is moving due to the convection currents. If you look carefully you many notice pepper rising and falling.


5. Put an ice cube into the water and see what happens. You should see the pepper at the top of the water move towards the ice cube and then sink to the bottom of the pot as it is carried by the convection currents.


6. Just for fun, put another ice cube into the water, but this time drop a bit of food coloring on the ice cube. You should see the food coloring sink quickly to the bottom and spread out as it is carried by the convection currents.


Did you see the convection currents? Hot water rising in some areas of the pot and cold water sinking in other areas of the pot carried the pepper and food coloring throughout the pot. This rising and sinking transferred heat through all the water causing the water in the pot to increase in temperature.


Heat was transferred from the flame of the stove to the water by convection. More accurately, heat was transferred from the flame of the stove to the metal of the pot by conduction and then from the metal of the pot throughout the water through convection.


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