$1 Word Search

Tuesday July 31, 2012

Have you ever heard of a dollar word search? It’s a special kind of puzzle where the letters in a word add up to a coin value. For example, an A is worth a penny, the letter B is worth two cents, C is worth three cents, and so on. Are you completely confused? That's okay!  Just watch the video and I’ll show you how it all works.

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Download Student Worksheet & Exercises

Were you able to use my hints to find some dollar words? Keep trying! It’s really fun and rewarding to find out which words work. Please add a comment below if you discover a new one. We would love to add it to our growing list of dollar words!

Exercises

  1. What is the word “bucket” worth?
  2. Determine the monetary value of the word “toilet.”
  3. What is a “starfish” worth?
  4. The shortest sentence in English is “Go.” How much is it equivalent to?

Which one of the following has the greatest monetary value?

  1. Supper, dinner, lunch
  2. Monday, Sunday, Tuesday

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Isn't that SUM-thing?

Tuesday July 31, 2012

This is a neat trick that you can use to really puzzle your friends and family. If someone gives you a three-digit number, you can actually figure out what the end result will be after you've received two additional numbers, but before you actually know what those numbers are. Does this sound confusing?  Watch the video and I’ll show you how it works.

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Download Student Worksheet & Exercises

Were you able to figure this problem out? The real trick is that you’re simply adding 1,998 to the first number that you received. No matter which other two numbers are given to you, make sure the number you write down makes each pair of numbers' sum 999. If you do this correctly twice, then the row of numbers you add together will be the same as the initial number plus 1,998. Try it out and let me know if it works for you!

Exercises

Predict the end result for the following numbers:

  1. 235
  2. 988
  3. 002
  4. 999
  5. 427
  6. 777
  7. 559
  8. What would be the difference between a number 769 and its predicted result based on the above knowledge?
  9. A mathematician was given a number x and gave its end result as 2877. What is the value of x?
  10. Suzanne was asked by her friend to predict the end results of 932 within a few seconds. If she was given 432 as one of the two additional numbers to complete the proof of the predicted number, which number did she write immediately afterwards?

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Playfair Cipher

Tuesday July 31, 2012

This is a super hard cipher to break.  It’s encoded by taking pairs of letters and numbers from a matrix. There are three rules to follow.


  1. If both letters are in the same row, then use the letters immediately to the right of each other. (Think of the rows as wrapping from the right end back around to that same row’s left end).
  2. If both letters are in the same column, then use the letters immediately below them. If necessary, the bottom letter wraps back around to the top of the same row.
  3. If the two letters or numbers are in different rows and in different columns, then each letter is replaced by the letter in the same row that’s also in the same column of the other letter. Basically, you find each intersection of the pair. Use the letter or number below the pair and then the one above the pair.

Play Fair sounds really complicated, but that also makes it a tough code to crack! Watch the video and I’ll explain it all for you.


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Download Student Worksheet & Exercises


Isn’t this cool? It makes a lot more sense when you see it in action, right? Remember: when decoding the Playfair cipher, you have to shift up instead of down and left instead of right. And it’s easy to make a mistake by encoding in the incorrect order. So always  double check your cipher before sending it on to the recipient. Mistakes make messages much harder for the decoder to interpret!


Exercises


  1. What is the name given to the following table?
A H M V L 3 Y D
X K B 5 P Z E O
N 7 W U F T 6 J
G R 2 Q C A I S

Use the table in 1 above to answer question 2 – 10.


What will be the cipher for the following?


  1. KB
  2. HR
  3. AR
  4. EU
  5. COME TO SCHOOL
  6. GO HOME THEN

Decode the following messages


  1. 73 3N SG YZ 6X
  2. SG MN YK A7 JO HD
  3. Why is it important the number of letters in the message to be encoded be even?

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Telephone Cipher

Tuesday July 31, 2012

Code machines – or cipher machines – can be used to encode and decode messages. One everyday example of a code machine that you can easily access is a telephone. Watch this video and I’ll show you how it works.


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Download Student Worksheet & Exercises


What do you think about the Telephone Code? Remember to get those slash codes just right in order to make decoding easier for the message receiver. (No pun intended!)


Exercises


Encode the following using the telephone keypad:


  1. COME BACK
  2. LEAVE TODAY
  3. HE ARRIVED
  4. THEY WENT
  5. HE IS COMING
  6. REVEAL
  7. GO AHEAD

Decode the following ciphers


  1. 1 6 3 7 4   2  2
  2. 8 64  8 3   3 5 4 6 4   3 6  6
  3. 2 8 7  8 7   2 5 4 2

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Invisible Writing

Tuesday July 31, 2012

This is an alternate method of secret writing that’s completely different from encoding and decoding message ciphers. It involves using special inks that are invisible until something is done to make them appear on the paper. There are hundreds of formulas to make these special inks and some formulas even have multiple ways to develop the ink. Some recipes involve special chemicals, but many invisible inks can be made using materials that you have in your home. Watch the video and I’ll share a few recipes and teach you more about this method.


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Some of these are really simple, right?  I like the wet and dry method a lot. When using the milk writing method, how do you think you would get the milk to change color so that the message could be read?
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Scytale

Tuesday July 31, 2012

In this video I’ll show you how to use a actual cipher machine called a scytale. This was first used in ancient Greek and Roman times, most notably by the Spartans. To make a scytale, use a cylinder with a piece of paper wrapped around it. Then simply print your message in rows that run along the length of the cylinder. When the paper is unwrapped, the message is scrambled!  Watch the video and I’ll show you the trick to proper message decoding.


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Download Student Worksheet & Exercises


Isn’t this cool?  It’s very important to make sure that the message’s intended recipient has a cylinder of the exact same size so that they can easily decode the message.


Exercises


  1. What is the name of the cryptographic machine that was first used by the ancient Greeks and in Roman times to send secret messages?
  2. What is the shape of the machine named above?
  3. Where is the message written when using this machine?
  4. Apart from the machine, what else is required to be able to encode the message?
  5. Who were the people who most notably used the type of cryptography named?
  6. What is the major problem that the recipient must figure out to easily decode the message?
  7. Is it true that first letter in the original message would be the first letter on the encoded message? Explain.

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Big Numbers

Tuesday July 31, 2012

Numbers really can be huge – some are too big to even imagine!  Have you ever seen a million pieces of candy? Or have you ever even tried to count to one million? In this video, we’ll try to figure out about how long it would take just to count to one million. I’ll also show you how to write some really big numbers!

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Download Student Worksheet & Exercises

So there are 31,536,000 seconds in a year, but you couldn’t spend all of your time counting. Simply saying larger numbers will take much longer than a second! So with lots of breaks for sleeping, eating, and homework, it would take more than a year to count to a million…and most people get bored with counting way before that.

Exercises

  1. How many seconds are there in one hour?
  2. How many seconds are there in a day?
  3. How many days does a leap year have?
  4. Write a number greater than but closer to a billion.(Note the difference between the two should be less than 50)
  5. Write a number lesser than but closer to a billion.(Note the difference between the two should be less than 50)

Write the following numbers out numerically:

  1. A thousand billion
  2. A thousand million
  3. A hundred hundred
  4. Write a number that is 1 less than 100,000,000,000

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Exponents

Tuesday July 31, 2012

Have you ever heard someone refer to a “million billion” of something? Is that more or less than a “billion million?” In this video, I’ll show you how to write down these numbers and figure out which one is larger.

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Download Student Worksheet & Exercises

Did one of these numbers sound bigger to you? To me, they’re both a strange way to say the exact same number – which is actually a quadrillion!

Exercises

Write out each number long-ways (with all the zeros written out):

  1. A thousand million
  2. A thousand billion
  3. Ten million
  4. A hundred billion

Write the exponential form (ten and a superscript) of the following numbers

  1. A thousand million
  2. A thousand billion
  3. Ten million
  4. A hundred billion

Determine the exponents of the following number if written in the form; ”ten and a superscript.”

  1. 10,000,000,000
  2. 100

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Factorials

Tuesday July 31, 2012

If I said “3!“, would you think the 3 is really excited, or that you have to shout the number?


In fact, it’s a mathematical operation called factorials, and boy are they fun! They may seem complicated at first, but they’re really a very basic concept. The exclamation point behind a number means that you multiply that number by each successively lower number, in order, until you get to one.


So 3! would be 3 x 2 x 1 = 6.


Take a look at the video for an explanation of how factorials work and how they can be used.


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Download Student Worksheet & Exercises


Can you see how factorials start to get really big, really quickly? The card deck is a really great example of this, because with 52 cards the factorial is 52!, which is a HUGE number. There are literally trillions and trillions and trillions of ways to arrange those cards.


Does 0! = 1 make sense to you?  If not, that’s okay. Just memorize this fact and tuck it away for later. It will come in handy some day in algebra and maybe even for calculus!


Exercises


  1. 6!
  2. 6!/4!
  3. How many ways can seven different cards arranged uniquely?
  4. 0! x 4!
  5. 3! x 4!
  6. 1! x 5!
  7. 2! x 0 x 6!
  8. 2! x 4!
  9. 3! x 2!
  10. 5! x 0! x 1! x 2!

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Checkerboard Paradox

Tuesday July 31, 2012

Once in awhile, mathematicians come up against something that really seems impossible on the surface. These seemingly “impossibilities” not only cause them to sit up and take notice, but often to create new rules about the way math works, or at the very least, understand math a little better.


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Be warned however, that some paradoxes are really false paradoxes, because they do not present actual contradictions, and are merely “slick logic” tricks. Other paradoxes are real, and these are the ones that shake the entire world of mathematics. There are several paradoxes that remain unsolved today. You can find a list of paradoxes here.


There are a lot of variations on the checkerboard paradox. Here’s one of my favorite paradox puzzles – can you explain it?


You’ll find need to download the PDF and cut out your four pieces.



Download Student Worksheet & Exercises


Need a HINT? I’ll give you a hint… look at the following picture:


If you cut the rectangle along the diagonal (the line that magically appears from one corner to the other) and then slide the lower triangle as shown, you can count the number of vertical lines and find that there are only nine! What happened to the tenth? You can make it magically appear if you slide the lower triangle back to its original position. So… my question to you is: Which is the line that has returned and where does it come from?


The secret is this: there is a progressive decrease in the length of the segments above the diagonal and a corresponding increase in the length of segments below. What happens is that eight of the ten lines are broken into two segments, then these sixteen segments are redistributed to form nine lines, each a trifle longer than before. Because the increase in the length of each line is slight, it is not immediately noticeable. In fact, the total of all these small increases exactly equals the length of one of the original lines. Therefore, there is actually not a line which vanishes.


Now… how would you explain the checkerboard paradox? Put your answer in the comment box below…


Exercises


Your exercise for this lesson is to not only challenge someone else with this problem, but be able to explain it to them in a way that they understand the solution.


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Probability

Tuesday July 31, 2012

In math, probability is how likely it is that something will occur (or not). Probability is expressed from a range from 0 to 1. A probability of zero means that a thing will definitely not happen – it’s impossible. But a probability of one means that it definitely will happen – it’s certain. Any number larger than 0, but smaller than 1 means that a thing might happen. The number 1/2, or one half, is right in the middle and it means there is a 50/50 chance. Do you think there’s a greater chance for a person to get struck by lightning, or to be hit by a meteorite?


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Download Student Worksheet & Exercises


Some key words that help with probability questions are OR and AND. When you see the word OR, it means you should be adding the possible outcomes to find out the probability whether one thing OR another will happen. The word AND means you will probably be multiplying to find the solution. Based on these rules and the information that I share in the video, what are your chances of being struck by lightning AND having a heart attack?


Exercises


  1. What is the probability of a coin showing tails when flipped?
  2. What is the probability of a coin showing heads twice in a row?
  3. What is the probability that heads or tails will show up in a toss?
  4. What is the probability that heads and tails will show up in two successive tosses?
  5. A die is rolled once: what is the probability that a four will show up?
  6. A die is rolled once: what is the probability that a three will show up?
  7. A die is rolled once: what is the probability that a four or a six will show up?
  8. A die is rolled twice: what is the probability that a four will show up in all the rolls?
  9. A die is rolled twice: what is the probability that a four and a two will show up?
  10. A die is rolled twice: what is the probability that the same number will show up in all the rolls?

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Three Doors

Tuesday July 31, 2012

Imagine that you are on a game show with a chance to win a car. There are three doors and the car is behind one of them. You just have to choose the correct door! You can use probability to get an possible advantage in choosing the correct door. Watch the video, and I will explain how it works.


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Download Student Worksheet & Exercises


So would you have changed your mind about your pick or stuck with the second door? Using probability, we can determine that door number 1 really is the door with the best odds for winning the car. Isn’t that interesting?


There were many math PhDs that disagreed with the right answer. There will always be someone who won’t believe it. But here’s the correct answer.


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Earthquakes!

Saturday January 28, 2012

When two blocks of the Earth slip past each other suddenly, that’s what we call an earthquake! From a physics point of view, earthquakes are a release of the elastic potential energy that builds up. Most energy is released as heat, not as shaking, during an earthquake. 90% of all earthquakes happen along the Ring of Fire, which is the active zone that surrounds the Pacific Ocean.


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The Earth has four main layers: the hard skin on the surface is the crust which extends only 30 miles; the hot magma section is a soupy mass of rock that extends approximately 1800 miles; and the core which is made out of two parts: the hot liquid metal outer core surrounds the solid nickel -iron inner core.


The plates on the crust float on magma, which is a lot like the consistency tar. The crust has seven main tectonic plates that slide around and can either slide apart from each other (called a normal fault that is usually found on the sea floor), collide into each other (called a thrust fault), or move in opposite directions (strike-slip fault) at different speeds. Where the plates are sliding apart on the sea floor, the temperature of the water can rise over 1200oF. Scientists measure the speeds of the plates moving from 1 to 10 inches per year.


There are three different waves that travel through the planet when an earthquake happens. The first waves are the compression-type “P-waves” (primary waves), which travel through the entire planet, including liquid water and solid rock. Most people don’t notice the P-waves, but they do notice the secondary “S-waves”, which follow 60-90 seconds after the P-waves. Following the S-waves are the surface waves, which are like when you wave a bed sheet up and down.


Earthquakes are detected and measured by many different types of instruments, like strain gauges, creep meters, tilt sensors, seismometers, x-ray imagery, and more. These detectors aren’t perfect, though. Earthquake detectors not only discover earthquakes but also glacier movement, nuclear explosions, meteor impacts, and volcano eruptions!


After you watch the video, click the link to do your seismology calculations to figure out both the epicenter and the magnitude of four different earthquakes:


If you’d like to measure the Earth’s Magnetic Pulse, you can do that here.


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Mystifying Superconductor Roller Coaster

Thursday November 24, 2011

When I was in 10th grade, my teammate and I designed what we thought was pretty clever: a superconductor roller coaster, which we imagined would float effortlessly above its magnetic track. Of course, our roller coaster was only designed on paper, because yttrium barium copper oxide ceramics had only just been discovered by top scientists.



Did you notice how it was smoking in the video? That’s because it was so cold! The usual problem with superconductors is that they need to be incredibly cold in order to exhibit superconductive properties.  Yttrium barium copper oxide (YBa2Cu3O7) was the first compound that used liquid nitrogen for cooling, making superconductors a lot less expensive to work with – you no longer needed a cryogenic lab in order to levitate objects above a magnet.



Recently, scientists have found a way to make an amazing superconductor by taking a single crystal sapphire wafer and coating it with a thin (~1µm thick) ceramic material (yttrium barium copper oxide). Normally, the ceramic layer has no interesting magnetic or electrical properties, but that’s when you’re looking at it at room temperature. If you cool this material below -185ºC (-301ºF), it turns out that the ceramic material becomes a superconductor, meaning that it conducts electricity without resistance, with no energy loss. Zero. That’s what makes it a ‘superconductor’.


To further understand superconductivity, it’s helpful to understand what normally happens to electricity as it flows through a wire. As you may know, energy cannot be created or destroyed, but can be changed from one form to another.


In the case of wires, some of the electrical energy is changed to heat energy. If you’ve ever touched a wire that had been in use for a while, and discovered it was hot, you’ve experienced this. The heat energy is a waste. It simply means that less electricity gets to its final destination.


This is why superconductivity is so cool (no pun intended.) By cooling things down to temperatures near absolute zero, which is as low as temperatures can get, you can create a phenomenon where electricity flows without having any of it converted to heat.


Why do superconductors float above magnets?

Scientists also figured out that superconductors and magnetic field really do not like each other. The Meissner effect happens when a superconductor expels all its magnetic fields from inside.


However, if you make your superconductor thin enough, you can get the magnetic field to penetrate in discrete quantities (this is real quantum physics now) called flux tubes (the blue lines that go through the disc).


Inside each of the magnetic flux tubes, the superconductivity is destroyed, but the superconductor tries to keep the magnetic tubes pinned in weak areas and any movement of the superconductor itself (like if you pushed it) causes the flux tubes to move, and this is what traps (or locks) the superconductor in midair.



If you’d like to experiment with superconductors yourself, check out this information.


PTC Testing

Friday November 18, 2011

We have done some extensive experiments on taste buds: how they are categorized, what tastes they recognize, and we have even mapped their location on your tongue. But we haven’t yet mentioned this fact: not all people can taste the same flavors!


So today we will check to see if you have a dominant or recessive gene for a distinct genetic characteristic. We’ll do this by testing your reaction to the taste of a chemical called phenylthiocarbamide (or PTC, for short). The interesting thing about PTC is that some people can taste it – and generally have a very adverse reaction. However, some people can’t taste it at all.


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Here’s what you need


      • 1 vial of PTC paper
      • family members



Download Student Worksheet & Exercises


Here’s what you do


  1. Put the PTC paper in your mouth. If you have the dominant gene, it will usually taste pretty bitter. It might also be sour or even a little sweet. If it tastes like a piece of paper, you have a recessive gene.
  2. After testing your paper, be sure to note whether you are a taster or non-taster.
  3. Now test at least five more people in your family and note their reactions as tasters or non-tasters. Also note their relationship to you.
  4. If you have enough PTC paper, make a genetic tree of your responses. Put Mom and Dad at the center and list you and your siblings branching out beneath them. Then list both sets of grandparents above each of your parents. Circle the names of family members who test positive and leave the negative testers uncircled.

What’s going on?


The gene that determines whether or not you can taste PTC is a part of your DNA (deoxyribonucleic acid). It is the genetic blueprint that you were born with and it determines everything about you: from hair color to the size of your feet. But DNA also plays an important role in how your five senses function. Colorblindness is a genetic deficiency in which a person cannot see colors has a difficult time with distinguishing them. It can range in severity. Some people who are colorblind can’t tell the difference between colors like red and green, but some see no colors at all. Everything looks like a black and white movie to them. Just like colorblindness, our taste sensitivity can vary. Maybe this explains why some people like liver and brussel sprouts and others can’t stand them!


So to relate this to our test, the ability to taste PTC comes from a gene. We know that if both of your parents can taste it, there is a high likelihood that you will be able to taste it, too. About 70%, or 7 out of 10, people can taste it. But what does it mean?  In truth, not a lot. It doesn’t mean you have a highly developed palate or a better sense of taste. It just means you are lucky enough to have inherited a gene that allows you to taste a disgusting, bitter chemical on a piece of paper. Congratulations!


Exercises


  1. What are the tiny hair-like organelles that send taste messages to your brain called?
  2. What are the bumps on your tongue called?
  3. What kind of trait does this experiment test?

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Basic Chemistry Safety Information

Friday November 18, 2011

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!


When you’re done storing your chemicals out of reach, watch this video:


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Now go grab your chemistry box and watch the video below. The packaging of your chemistry set might be a little different, but the important concepts are the same. We’re going to learn how to read the secret code on the chemicals, which parts are which inside the set, and get our chemistry lab ready to work with.



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.



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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Stethoscope

Friday November 18, 2011

Stethoscopes are instruments used to amplify sounds like your heartbeat. Your doctor is trained to use a stethoscope not only to count the beats, but he or she can also hear things like your blood entering and exiting the heart
and its valves opening and closing. Pretty cool!


Today you will make and test a homemade stethoscope. Even though it will be pretty simple, you should still be able to hear your heart beating and your heart pumping. You can also use it to listen to your lungs, just like your doctor does.


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Here’s what you need


  • 3 12-inch lengths of rubber hose
  • 1 “T” connector
  • 1 funnel



Download Student Worksheet & Exercises


Here’s what you do


  1. Take two pieces of hose and work them onto the top ends of the “T” connector. Put the remaining piece of hose onto the bottom of the “T.” The tool you have made should look like a simple stethoscope, but there are no super cold metal end pieces to worry about with yours.
  2. Put the funnel into the bottom hose – the one hanging from the bottom of the “T” connector. You know have a functioning stethoscope. One word of warning: NEVER YELL INTO THE FUNNEL WHILE THE STETHOSCOPE IS ATTACHED TO SOMEONE’S EARS. THIS COULD DAMAGE EAR DRUMS!
  3. Gently insert the side tubes into your ears. Put the funnel on your chest, just to the left of your breastbone. Listen for your heartbeat. If you are in a sufficiently quiet room you may even be able to hear the opening and closing of your heart’s valves.
  4. After you’ve found your hear, try moving the stethoscope to various areas of your chest and listen for different sounds made by your heart. Ask if you can listen to a friend or family member’s heart. Are the sounds made by another heart the same or different?
  5. Now listen to your lungs, placing the end of the stethoscope just above and to the left of the bottom of your ribcage (Point A), to the right of the bottom of your ribcage (Point B), and just below where your ribs start (point C). Also listen in the middle of your back to the left (point D) and right of your spine (point E). In each spot, take a deep breath and listen for the sound of air entering and exiting the lungs.
  6. For your data records, record how many times your heart beats in a minute while you are quiet and sitting.
  7. Next, do 100 jumping jacks. Sit down immediately and check your heart. Record the number of beats per minute for jumping jacks in your data.
  8. Finally, go outside and run for 3 minutes, non-stop. Then sit and immediately check your heart rate one more time. Record the beats per minute for running in your experiment data.

What’s going on?


Exercise creates a demand for oxygen in your muscles, which is received from work done by your heart and lungs. They get a message from your brain and start to work harder. You can see the proof of their hard work in your recorded data.


Exercises


  1. Approximately how big is your heart?
  2. Which body system is the heart a part of?
  3. What are some of this system’s jobs?
  4. How many chambers does your heart have and what are they called?
  5. How did the heart rate change when you exercised?

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What’s Your Lung Capacity?

Friday November 18, 2011

Today you will make a calibrated, or marked, container that you will use to measure your lung capacity. You will fill the calibrated container with water, slide a hose into it, take a really deep breath, and blow in the hose. As the air in your lungs enters the container, it will push out the water inside. Just blow as long and as much as you can, then when you flip the bottle over you will be able to read the amount of water you have displaced. If you will subtract the water displaced from the total amount of water in the bottle, the result is your lung capacity.


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Here’s what you need


    • 1 2-liter soda bottle
    • 1 black marker, permanent
    • 1 12” length of rubber hose
    • 1 large plastic bowl
    • 1 cup measure


Download Student Worksheet & Exercises


Here’s what you do


  1. Fill the 1 cup measure with water. Pour this into the 2-liter bottle and mark the water level with a line using the black, permanent marker. Also, write 1 cup next to the line. Keep adding water, one cup at a time, marking each new 1 cup increment until you have filled the bottle with water.
  2. Now flip the newly-filled bottle of water over 1 cup measure until the cup is about 1/3 full. Put one end of the rubber hose in the top of the bottle (which should be now under water).
  3. Take a really deep breath – as deep as you can – and blow your breath out into the tube. Continue to blow until you can’t push any more air into the bottle. As air goes in the bottle, it pushes an amount of water equal to its volume out and into the bowl.
  4. Put the lid on the bottle and turn it over before lifting it out of the water. How much water is left in the bottle? Subtract this amount from 8.5 cups. This should be your lung capacity.
  5. Record your lung capacity in your data records as, “My lung capacity is ____________ cups.”  You can convert this number to milliliters by multiplying by 0.24. For example, 19 cups would equal 4.5 liters.

What’s going on?


A person who is 70 years old has breathed about 600,000,000 times in their life. But they have also breathed a lot of air – about 13,000,000 cubic feet. This is enough air to fill 52 blimps!


A man’s lungs have a greater capacity than a woman’s – it’s about 6 liters for a man and 4.2 liters for a woman. And since a grown-up has a greater lung capacity than a kid, it makes sense that a 10-year old might breathe 20 times per minute when a grown-up might breathe only 12 times in a minute.


Exercises


  1. Which body system are your lungs a part of?
  2. What are some other parts in this system?
  3. Explain this system’s major function.

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Basic Chemistry Safety Information

Friday November 18, 2011

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!


When you’re done storing your chemicals out of reach, watch this video:


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Now go grab your chemistry set box and click this link to find out which set you have. We’re going to learn how to read the secret code on the chemicals, which parts are which inside the set, and get our chemistry lab ready to work with.


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 chemistry lab kit. The manual included in the C1000 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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Making Litmus Solution and Paper

Friday November 18, 2011

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.



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]


Magnesium Battery

Friday November 18, 2011

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!



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.


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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Making Copper

Friday November 18, 2011

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


Download Student Worksheet & Exercises


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


CuSO4 + H2O (Copper sulfate is added to water)


CuSO4 + H2O –> 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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Making Chlorine

Friday November 18, 2011

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, including: 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.)


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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Electrochemistry

Friday November 18, 2011

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


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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Working Lung Model

Friday November 18, 2011

Food and air both enter your body through your mouth, diverging when they reach the esophagus and trachea. Food goes to the gastrointestinal tract through your esophagus and air travels to your lungs via the trachea, or windpipe.


You will be making a model of how your lungs work in this lab. It will include the trachea, lungs, and the diaphragm, which expands and contracts as it fills and empties your lungs.


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Here’s what you need


    1. 1 2-liter soda bottle, emptied and cleaned
    2. 1 pair of scissors
    3. 1”Y” valve hose connector
    4. 3 round, 9-inch balloons
    5. 1 #3 one-hole stopper
    6. 1 length of hose, 8-inch
    7. 2 rubber bands
    8. 1 jar of petroleum jelly


Here’s what you do


  1. Cut off the bottom of the 2-liter bottle. Ask an adult for help.
  2. Take the “Y” valve and secure the two balloons to the top branches with the rubber bands.
  3. Put a tiny bit of petroleum jelly on the end of the hose to make it easier to insert into the #3 stopper. Pull 6 inches of hose through the stopper and then thread the hose through the bottle’s neck. Insert the stopper into the top of the bottle.
  4. Put the end of the hose (that is now inside the bottle) into the base of the “Y” valve (which now has balloons on its other branches). Pull the hose through the stopper a bit. Also, pull the lungs up toward the top of the bottle.
  5. Tie a knot in the third, unused balloon. Cut it in half and stretch the part with the knot over the open bottom of the soda bottle. Make sure the bottom balloon is as tight as it can be.
  6. Grab the bottle with one hand, the knot at the bottom of the balloon with the other. Carefully pull the knot on the balloon down. What happens to the balloons in the bottle? Now let go of the knot and observe how this affects the balloons. Note your observations in the experiment’s data.
  7. Sketch your model and label its trachea, lungs, and diaphragm.

What’s going on?


By placing a stopper in the top of the bottle and putting the stretched rubber balloon on the bottom, you have created an enclosed system. The tube at the top of the bottle is the only way for air to enter or exit the model’s lungs. Pulling down on the balloon’s knot reduced the air pressure inside the lungs. As compensation, air was pushed down into the tube to equalize the pressure. This caused the balloon lungs to expand. When you released the knot, the air pressure forced the air out of the balloons.


If you need more help with identification, the tube acts as the trachea, the balloons are the lungs, and the balloon with the knot at the bottom is the diaphragm.


Did you know that an average person breathes about 24,000 times each day? If you live to be 70 years old, that means about 600,000,000 breaths. Make them count!


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Ammonia Experiments

Friday November 18, 2011

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 plants 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


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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Testing Spit Samples

Friday November 18, 2011

Digestion starts in your mouth as soon as you start to chew. Your saliva is full of enzymes. They are a kind of chemical key that unlock chains of protein, fat, and starch molecules. Enzymes break these chains down into smaller molecules like sugars and amino acids.


In this experiment, we will examine how the enzymes in your mouth help to break down the starch in a cracker. You will test the cracker to confirm starch content, then put it in your mouth and chew it for a long time in order to really let the enzymes do their job. Finally you will test the cracker for starch content and see what has happened as a result of your chewing.


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Here’s what you need


    1. 1 package of soda crackers
    2. 1 5” pie tin
    3. 1 craft stick
    4. 1 0.5 oz bottle of iodine
    5. 1 pre-form tube
    6. 1 1 mL plastic pipette
    7. water



Download Student Worksheet & Exercises


Here’s what you do


  1. Take a cracker from the package and put it in the pie tin. Use your thumb to mash it up, making the pieces as small as possible. Add a small amount of water with the pipette. Mix everything up with the craft stick to make a mash of cracker.
  2. Now fill the pipette with iodine. When iodine comes in contact with starch, it changes in color from reddish-brown to a dark blueish-black. Take the pipette and squeeze a few drops onto the cracker mash in various spots. Record what you see in your experiment data.
  3. Take another cracker and chew it up for about 2 minutes. Do you notice any flavor changes as you are chewing? If so, note this. Be particularly aware of any sweet flavors.
  4. Spit the mash into the pre-form tube once you have chewed for 2 minutes. Use the pipette of iodine to add a few drops of iodine to the chewed mash. Note any change in color. If there is no starch, the iodine will stay reddish-brown in color. If starch is present, you will see the color change to a very dark blue-black as it did in step 2. Record what you see in your data.

What’s going on?


This lab gives you a good idea of what happens in digestion, which starts as soon as food enters your mouth. Actually, the process can start even before this as your body prepares for food. Have you ever had a wonderful smell make your mouth water? This is your body’s way of getting ready to get to work digesting that delicious food.


Once you take a bite and the enzymes start to do their job of breaking large, more complex molecules into smaller particles. In this experiment, starch got broken down into simple sugars that your body could easily move around and use as fuel.


There are three sets of saliva-secreting glands in your mouth. They include a gland in the back of your throat called the parotoid gland, one in your lower jaw called the submandibular gland, and the sublingual gland which is under your tongue. The three work together to secrete up to 2 liters of saliva each day.


Exercises


  1. What is the first step in the digestive process?
  2. How does saliva help to digest food?
  3. Name one or more of the main salivary glands and where they are located.

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Energy from Sugar

Friday November 18, 2011

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


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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Getting Air from Water

Friday November 18, 2011

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


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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Working with Cataylsts

Friday November 18, 2011

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 (MSDS) 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.


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


Download Student Worksheet & Exercises


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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Hydrogen Peroxide

Friday November 18, 2011

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.


C3000: Experiment


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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Generating Oxygen

Friday November 18, 2011

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


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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Detonating Bubbles

Friday November 18, 2011

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


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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Desalination

Friday November 18, 2011

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


Download Student Worksheet & Exercises


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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Heart Rate Monitoring

Friday November 18, 2011

When you exercise your body requires more oxygen in order to burn the fuel that has been stored in your muscles.  Since oxygen is moved through your body by red blood cells, exercise increases your heart rate so that the blood can be pumped through your body faster. This delivers the needed oxygen to your muscles faster. The harder you exercise, the more oxygen is needed, so your heart and blood pump even faster still.


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Here’s what you need


    • 1 clock with a second hand
    • 1 pencil



Download Student Worksheet & Exercises


Here’s what you do


  1. While sitting quietly, place your first two fingers of one hand onto the wrist of the other hand. Feel for the pulse of your radial artery. Practice taking your pulse in intervals of 6 seconds.
  2. After you have had some practice with the 6 second interval, take your pulse for this amount of time and multiply it by 10. The 6-second rate times 10 is your heart rate per minute. Record each for experiment data.
  3. Now stand up and do 50 jumping jacks. When done, sit down immediately and check your pulse. Again, record the 6-second pulse rate, multiply it by 10 and also record the pulse rate per minute.
  4. Finally, go outside and run around as fast as you can without stopping for 3 minutes. Again, immediately sit and take your pulse. Record the 6-second rate, multiply it by 10 and get your heart rate per minute.

What’s going on?


Exercising means your muscles need more oxygen. They ask your brain to tell your heart and lungs. When your heart gets the message, it starts to beat harder. Your lungs work harder, too. Together, your heart and lungs work as a team to provide the needed oxygen supply to your muscles. You can identify that this process is occurring by your heart rate increase and more rapid breathing rate.


Did you know that your heart is about the size of your fist? It is actually a muscle and it pumps more than a gallon of blood through your body each minute! An average heart rate is 70 beats per minute, but this can vary depending on age and fitness level. Based on 70 bpm, your heart will beat around 100,000 times per day. That’s more than 36 million beats a year!


Exercises


  1. Explain how to take a pulse.
  2. What units do we use to measure pulse?

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Carbon Dioxide

Friday November 18, 2011

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


Download Student Worksheet & Exercises


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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Zinc Dust

Friday November 18, 2011

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


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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Burning Sulfur

Friday November 18, 2011

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


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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Acids and Bases

Friday November 18, 2011

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


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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Detecting Carbon Dioxide

Friday November 18, 2011

An oxygen and carbon dioxide exchange takes place in your bloodstream. When you breathe air into your lungs it brings in oxygen, which is carried from your lungs by red blood cells in your bloodstream. Cells of your body use the oxygen and carbon dioxide is produced as waste, which is carried by your blood back to your lungs. You exhale and release the C02. You will study this exchange in today’s lab.


You will be using a pH indicator known as bromothymol blue. When you exhale into a baggie, the carbon dioxide will react with water in the bag. This reaction produces carbonic acid, which starts to acidify the water. More breathes in the bag equal more carbon dioxide, which equal a lower (more acidic) pH. You will notice the bromothymol will turn green when the pH of the water is right about 6.8 and it will turn yellow when the pH drops further to 6.0 and lower.


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Here’s what you need


    • 1 1 oz. bottle of bromothymol blue
    • 1 straw
    • 1 resealable baggie
    • 1 bottle of ammonia
    • 1 pipette
    • water


Download Student Worksheet & Exercises


Here’s what you do


  1. Pour about 2 ounces of water into the baggie and add two capfuls of the bromothymol blue into it. Close the baggie well and swish the solution around inside it gently to mix. Note the color of the solution for your data record.
  2. Open the baggie a tiny bit and put the straw inside, but DO NOT drink the solution! It could make you sick. Close the bag tightly around the straw and gently blow into the solution. Again, be careful not to suck on the straw.
  3. Watch the color of the solution closely as you continue to blow into the solution and create bubbles of carbon dioxide gas. The color will change to a sea green color and then eventually it will change to bright yellow. Note each color change in your records.
  4. You can return the solution to blue by slowly adding a base – such as ammonia – to the solution in the bag. Bleach will also work. Please ask an adult to help with this. Add one drop at a time, shaking after each addition to mix the solution. You will be able to observe when the pH starts to change back by the color of the solution. It should turn back to green and then to blue.

What’s going on?


Bromothymol blue will change color in a pH range from 6.0 to 7.6.  It is an acid/base indicator. Its basic solution is at a pH of 7.6 or above – this is when it is blue. In acidic conditions, it will turn yellow – this is a pH of 6.0 or below. And when it’s in between the two, it will be the sea green color that you observed in your baggie.


Because carbon dioxide is a little acidic, when we breathe it out into the water and bromothymol blue solution its bubbles start to lower the pH. You saw a small change in pH with the sea green color, but as you continued to exhale and add carbon dioxide, the solution became more and more acidic. This eventually resulted in a pH at or below 6.0 and a bright yellow solution.


In order to exchange oxygen with carbon dioxide in your lungs, they have over 300,000,000 teeny little air sacs calls alveoli. In one minute, you breathe approximately 13 pints of air.


Exercises


  1. What is pH and how it is useful?
  2. What does a yellow color indicate with bromothymol blue?
  3. Is CO2 acidic or basic?

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Making Sodium Hydroxide

Friday November 18, 2011

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


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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Potassium Permanganate

Friday November 18, 2011
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.

[am4show have='p9;p52;p91;' guest_error='Guest error message' user_error='User error message' ] 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



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

Click here for Homework Problem Set #14

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Potassium Hexacynoferrate (Reagant)

Friday November 18, 2011
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.

[am4show have='p9;p52;' guest_error='Guest error message' user_error='User error message' ] 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

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.

Click here to go to next lesson on Characteristics and capacity of buffers

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Iodine

Friday November 18, 2011
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). 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?

[am4show have='p9;p52;p91;' guest_error='Guest error message' user_error='User error message' ] 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





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.

Click here to download Equilibrium Constants and Reaction Mechanisms.

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How to Get Hydrogen from Zinc

Friday November 18, 2011

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


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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Hydrogen Bromide

Friday November 18, 2011
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.

[am4show have='p9;p52;' guest_error='Guest error message' user_error='User error message' ] 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: Experiment



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.

Click here to download Homework Problem Set #9.

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Hydrogen Chlorine Gas

Friday November 18, 2011

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.


[am4show have=’p9;p52;’ guest_error=’Guest error message’ user_error=’User error message’ ]


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


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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Shopping List for Unit 19

Thursday November 17, 2011

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).


Here’s how to use this shopping list: First, look over the list and circle the items you already have on hand. Browse the experiments and note which ones use the materials you already have. Those are the experiments you can start with. After working through the experiments, your child might want to expand and do more activities. Make a note of the materials and put them on your next shopping trip OR order them online using the links provided below.


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). Are you ready?


Shopping List for Unit 19: Click here for Shopping List for Unit 19 Online Experiments.


Material List:


Note: These materials listed here are only for the experiments listed in Unit 19 online. (There are different experiments listed in the downloadable Lesson Plan.) If you’d like to do the additional experiments within the Lesson Plan, download the Unit 19 Lesson Plan document and you’ll find the materials list inside.


Robotic Hand
five flexible straws
scrap of cardboard (at least as big as your hand)
five rubber bands
5 feet of string or thin rope


Tasty Tastebuds
1 partner
1 blindfold
1 cup of water
1 plate
1 lemon
2 toothpicks
1 sugar cube
1 salty cracker
1 piece of dark chocolate
1 pencil


Chemical Fingerprinting
1 oz. bottle of baking soda
water
1 sheet of goldenrod paper
1 paper towel
1 magnifying lens


Nerve Tester
1 large paper clip
1 metric ruler
1 partner


Mapping your Tongue
4 cotton swabs
5 wax cups
1 bag of black tea
1 bottle of red vinegar
2 packages of sugar
2 packages of salt
1 microwave
water
1 spoon
1 partner


Detective Boxes
4 shoeboxes with lids
1 soup can
1 pair of scissors
1 sheet of sandpaper
1 sheet of wax paper
1 sheet of flannel fabric
1  plastic bag
1 glue gun
1 pair of gloves
Partners


Finger Thermometers
3 glasses
1 Celsius/Fahrenheit thermometer
1 clock with second hand
hot water
cold water
ice cubes (optional)
room-temperature water


Diffusion
1 onion
1 lemon
1 bottle of ground cinnamon
1 clove of fresh garlic
1 garlic press
1 pile of fresh coffee grounds
1 kitchen knife
1 cutting board
1 variable-speed fan
1 clock with a second hand


Foggy Hands
1 gallon baggie
1 string, 12 inches long
1 assistant
1 clock


Scent Matching
10 small containers with lids
10 cotton balls
1 bottle of lemon juice
1 cup of black coffee
1 bottle of vanilla extract
1 bottle of cinnamon oil
1 bottle of soy sauce
1 black felt marker
1 assistant


Sound Whackers
1 desk
1 metric ruler


Sound Speed
3 baggies, resealable
sand
water
air
1 desktop
1 spoon
1 partner


Big Ears
2 styrofoam cups, 12 oz.
2 styrofoam cups, 32 oz.
1 pair of scissors
1 kitchen timer


Sound Matching
10 film canisters (for 53 mm film rolls)
beans
rice
sawdust (or pencil shavings)
paperclips
pennies
1 black, felt marker
assistant


Water Lens
1 washer, 3/8 inch inside diameter
1 microscope slide
1 container of petroleum jelly
1 piece of newsprint with a lot of type
1 pipette or dropper
water


Camera Eyes
1 dark room
1 light switch
1 partner
1 pencil


Disappearing Frog Experiment
1 frog and dot printout
1 meter stick
1 scrap piece of cardboard


Eyeballoon
1 biconvex lens
1 round balloon, white, 9 inches
1 assistant
1 votive candle
1 black marker
1 book of matches
1 metric ruler


Detecting Temperature Changes
1 measuring cup
1 bottle of calcium chloride
1 bottle of ammonium nitrate
2 resealable baggies
water


Rubber Eggs
4 fresh chicken wing bones, meat removed
1-16 oz. bottle of distilled white vinegar
2-12 oz. plastic cups
1 fresh egg
1 spoon


Cooling and Heating
1 bottle of rubbing alcohol
1 cotton ball
1 liquid crystal thermometer strip
1 cotton glove


Inside Bones
1 toilet paper tube
50-100 straws
1 roll of tape
1 book


Tricking your Muscles
1 partner
1 clock with second hand


Testing Muscle Strength
1 bathroom scale
1 pencil
1 partner


Visual Reflex
1 metric ruler
5 volunteers


Tendon Reflex
1 knee
1 partner


Detecting Plaque
1 4-pack of red disclosing tablets (ask for dentist for a sample pack)
1 clear plastic cup
1 mirror
1 red crayon
water


Testing Spit Samples
1 package of soda crackers
1 5” pie tin
1 craft stick
1 0.5 oz bottle of iodine
1 pre-form tube
plastic pipette or dropper
water


Seeing Your Pulse
1 lump of modeling clay or plastic putty
1 stopwatch
1 coffee stirrer straw
1 partner


Swallowing
1 tennis ball
1 pair of old nylons
1 pair of scissors


Working Lung Model
1 2-liter soda bottle, emptied and cleaned
1 pair of scissors
1 Y valve hose connector
3 round, 9-inch balloons
1 #3 one-hole stopper
1 length of rubber hose, 8-inch
2 rubber bands
1 jar of petroleum jelly


PTC Testing
1 vial of PTC paper
family members


Human Levers
1 body


What’s Your Lung Capacity?
1 2-liter soda bottle
1 black marker, permanent
1 12” length of rubber hose
1 large plastic bowl
1 cup measure


Consuming Oxygen
1 aluminum tart pan
1 votive candle
1 book of matches
1 clear drinking glass, 12 or 16 oz.
1 dime
water
1 pair of goggles


Detecting Carbon Dioxide
1 1 oz. bottle of bromothymol blue
1 straw
1 reasealable baggie
1 bottle of ammonia
1 pipette
water


Heart Rate Monitoring
1 clock with a second hand
1 pencil


Stethoscope
3 12-inch lengths of rubber hose
1 “T” or “Y” connector
1 funnel


Robotic Hand

Tuesday November 15, 2011

Your body moves when muscles pull on the bones through ligaments and tendons. Ligaments attach the bones to other bones, and the tendons attach the bones to the muscles.


If you place your relaxed arm on a table, palm-side up, you can get the fingers to move by pushing on the tendons below your wrist. We’re going to make a real working model of your hand, complete with the tendons that move the fingers! Are you ready?


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Here’s what you need:


  • five flexible straws
  • scrap of cardboard (at least as big as your hand)
  • five rubber bands
  • 5 feet of string or thin rope (and a lighter with adult help if you’re using nylon rope)
  • hot glue with glue sticks
  • scissors
  • razor



Download Student Worksheet & Exercises


Exercises


  1. What types of muscles are connected to our bones?
  2. Which type of connective tissue connects our muscles to our bones?
  3. What do extensor tendons in our wrist do?
  4. What do flexor tendons do?

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Chemical Fingerprinting

Tuesday November 15, 2011

Did you know that the patterns on the tips of your fingers are unique? It’s true! Just like no two snowflakes are alike, no two people have the same set of fingerprints. In this experiment, you will be using a chemical reaction to generate your own set of blood-red prints.


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Here’s what you need


  • 1 oz. bottle of baking soda or sodium carbonate (washing soda)
  • water
  • 1 sheet of goldenrod paper
  • 1 paper towel
  • 1 magnifying lens


Download Student Worksheet & Exercises


Here’s what you do


  1. Pour a couple teaspoons of the baking soda (sodium carbonate) into a cup of water. Swish your right index finger in the damp baking soda and then roll that finger on the goldenrod paper. This should leave a bright red fingerprint on the paper. Label it right index.
  2. Continue the procedure for each finger on both hands to make a full set of prints. Be sure to label each fingerprint as you make it to identify which print goes to each finger. Don’t forget to make prints of your thumbs!
  3. Compare your prints to the basic patterns in the guide. Check for features such as whorls or loops and label them appropriately on your prints. Use abbreviations such as A for accidental, PW for plain whorl, and DL for double loop.
  4. After you have identified the dominant pattern on each of your fingertips, prepare a simple chart for each hand to record the data by finger.
  5. When you are finished studying your own prints, ask a volunteer to let you make prints of their fingers.

What’s going on?


Goldenrod paper is made using phenolphthalein, a chemical that turns red when exposed to materials with relatively high pH. Baking soda (or sodium bicarbonate) is a base which has a pH of about 8.5. Rolling your baking soda covered fingers on the goldenrod paper creates a chemical reaction which produces a red fingerprint.


Exercises


  1. What are the three main types of patterns on fingerprints? Describe each.
  2. How do fingerprints have the potential to help solve crime?
  3. Why does baking soda (or washing soda) show up red on the paper?
  4. What kind of pH do bases have?
  5. What kind of reaction do we see when the red fingerprints show up on the paper?

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