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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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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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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Did you know that your tongue can taste about 10,000 unique flavors? Our tongues take an organized approach to flavor classification by dividing tastes into the four basic categories of sweet, sour, salty, and bitter.

For this experiment, you will need a brave partner! They will be blindfolded and will be attempting to guess foods. Relying only on their sense of taste, they will try to determine what kind of foods you are giving them.

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Here’s what you need

• 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

Download Student Worksheet & Exercises

Here’s what you do

1. (NOTE: Make sure your partner is not around for the first step!) Prepare a plate with a piece of lemon on a toothpick, a sugar cube, a really salty cracker, and a piece of dark chocolate, which will also be on a toothpick.
2. Blindfold your partner before they see the plate. Explain that you’re going to give them food samples. Their job is to taste each sample, one at a time, and then determine whether the food is sweet, sour, salty, or bitter. After they have provided a category, see if they can tell you the specific flavor of the food. They should use the water between samples in order to rinse their mouth and prepare for the next food.
3. Record data and observations for each individual food item. Be sure to list each food, your partner’s group classifications (sweet, sour, salty, or bitter) and what specific flavors that they note.

 What’s going on?

When you put food in your mouth, saliva immediately begins to break it down. Saliva mixes with food and makes a solution, which then takes the food (and its flavor) to the taste pores. There, receptors determine the chemical structure and send this information to your brain, which then decodes and categorizes the taste. The exact nature of the secret code relayed between your taste receptors and your brain is still a mystery. Maybe someday you can help to figure out the science behind it!

Did you know that humans have about 7500 taste buds? That’s a lot compared to most chickens, which only have about 24, total. But it’s a pretty small amount compared to catfish. They have over 175,000 taste buds! Can you imagine what your favorite dessert might taste like if you had that many? I wonder if it would be a good thing, or maybe too much information. Perhaps we are better off with our own perfect number of taste buds!

Exercises

1. How does saliva help with tasting?
2. What helps to decode the chemical structure of a food so that the brain can determine its taste type?
3. Why do foods sometimes become less strong as we age?

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The tongue has an ingenious design. Receptors responsible for getting information are separate and compartmentalized. So, different areas on the tongue actually have receptors for different types of tastes. This helps us to separate and enjoy the distinct flavors. In this experiment, you will be locating the receptors for sweet, sour, salty, and bitter on the tongue’s surface.

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Here’s what you need

• 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
• 1 blindfold

Download Student Worksheet & Exercises

Here’s what you do

1. Put 3 ounces of water into the first of the wax cups. Bring it to a boil in the microwave and have an adult help you add a teabag. This will make your bitter cup. Let it sit for 5 minutes. While it is steeping, you can prepare the other cups.

2. Fill the remaining cups with 2 ounces of water each. Prepare them as follows:

A.      For the sweet cup, add two packages of sugar to the warm water in one of the cups. Stir until well dissolved.
B.      For the sour cup, add 2 ounces of red vinegar to another cup and stir well.
C.      For the salty cup, put two packages of salt into the final cup. Stir until dissolved.
D.      The last step in cup preparation is to discard the tea bag that has been steeping in the first cup.

3. Now put the blindfold on your partner and have them stick out their tongue.  Dip the first swab into the tea. Using the diagram as a guide, swab each area one at a time: A, B, C, and D.  Ask your partner to identify the flavors as sweet, sour, salty, bitter, or can’t tell  as you swab each individual area. Record your partner’s response for each area.

4.Your partner should rinse out their mouth with water after testing the bitter tea. Then test each of the remaining solutions, one at a time in the same manner.

What’s going on?

Humans can identify thousands of distinct tastes, but we only have four types of taste receptors. When you take a bite of something flavorful, your saliva starts to dissolve it immediately. This solution of flavor and saliva goes to your taste buds and is then interpreted by your brain as sweet, sour, salty, or bitter.

The taste buds have taste receptors which bind to the structure of certain molecules: sweet receptors recognize hydroxyl groups (OH) in sugars, sour receptors find acids (H+, such as the citric acid in a lemon), salt receptors respond to metal ions (like Na+ in table salt), and bitter receptors are triggered by alkaloids. These are bases which contain nitrogen.  It’s interesting to note the location of the bitter taste buds – they are on the back of the tongue.  Since many poisons are alkaloids, their bitter taste may actually trigger vomiting.

Anyone who’s had a stuffy nose can tell you that smell plays a big role in our ability to taste. This makes sense because we know that we can only really taste the 4 distinct true flavors of sweet, sour, salty, and bitter. Our nose works in partnership with our tongue to allow us to identify more complex flavors.

Exercises

1. How many different types of taste receptors do we have? What are they?
2. Can you still taste food when you have a stuffy nose?
3. Which taste receptors recognize the hydroxyl group?

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  t6

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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The buildup of things like food and bacteria where your gums and teeth meet, and also between your teeth, is called plaque. Where plaque lives is also where the bacteria turns the sugar in your mouth into harmful acids that attack your teeth’s enamel and can lead to gum disease. Regular brushing is a great way to remove plaque and keep your mouth healthy.

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Here’s what you need

• 1 4-pack of red disclosing tablets
• 1 clear plastic cup
• 1 mirror
• 1 red crayon
• water

Download Student Worksheet & Exercises

Here’s what you do

1. Disclosing tablets are designed to identify plaque by turning it red. Remove a pill from the packaging and put it in your mouth. Chew it up thoroughly but don’t swallow it. Be very careful not to get any of the dye on clothing or anything else that might stain. The color is very difficult to remove!
2. Take the cup full of water and rinse out your mouth very well. Spit the water out into the sink. Check your mouth in the mirror. All of that red is plaque! Draw a picture of your mouth and use the red crayon to note where the plaque is attacking your teeth and gums.
3. You should have a total of 4 pills in the package. You can test other members of your family, or if you would prefer, test yourself over a period of a few days after you have had a chance to observe and identify where you should be doing a better job of tooth-brushing.

What’s going on?

When you chew the tablets they start to dissolve and mix with your saliva. This makes a water soluble dye that affixes to the bacteria and other particles in your mouth. The dye is absorbed by the bacteria, so it holds onto it even after your mouth is rinsed. This enables you to identify the unbrushed areas in your mouth.

Have you ever counted your teeth? They started to appear when you were a baby – about 6 months old or so. Kids have 20 deciduous, or baby teeth. These will fall out and the adult teeth grow in to replace them. Adults usually have 32 total teeth.

Exercises

1. Why does this experiment work at detecting plaque?
2.  How can dentists and moms use this to make sure you’re doing a good job brushing?
3.  What is plaque, and why is it bad for you?

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Involuntary responses are ones that you can’t control, but they are usually in place to help with survival. One good example is when you touch something hot. Your hand does not take the time to send a message to your brain and then have the brain tell your hand to pull away. By then, your hand might be seriously hurt! Instead, your body immediately removes your hand in order to protect it from further harm.

Today you will test an involuntary reflex by using the tendon reflex test. A thick, rubbery band called the patellar tendon holds your knee cap in place. Having one leg on top of the other not only stretches the tendon, but it also makes it possible to see a reaction. You can test the reflex by giving your tendon a tap and watching what happens.

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Here’s what you need

1. 1 knee
2. 1 partner

Download Student Worksheet & Exercises

Here’s what you do

1. Sit with your legs crossed at the knee on the edge of your seat. Reach forward and see if you can feel the patellar tendon. It is right below your knee cap.
2. Ask your partner to gently tap the tendon with the outside edge of their hand. This will look like a careful little karate chop. If your partner gets the right spot it will be obvious. You will notice your leg kick out a little in a reflex reaction.
3. Your partner can try other spots on the tendon if reaction isn’t achieved at first. If it hurts, stop right away! It’s possible that you might not have a tendon response reflex. Not everyone does and that is perfectly normal.

What’s going on?

There are three main parts that make up your peripheral nervous system. They are the autonomic nerves, which control reflexes like the one we have studies here. Autonomic nerves also send information to your organs, blood, and other parts of the body. The second part of your peripheral nervous system is made up of the nerves that deal with the five senses. The last part is your motor nerves. They help you to move the muscles in your body and are responsible for voluntary reactions.

The tendon reflex is in place because the knee is such a sensitive and vulnerable part of the body. When the tendon is stretched out and bumped, your body tries to move the leg and knee out of harm’s way so that it won’t get hurt. As you could probably tell, it’s an involuntary response that neutralizes any conscious, voluntary control that your brain has over the leg through the motor nerves.

Exercises

1. What are the main parts of the nervous system?
2. What are the two parts of the peripheral nervous system and what are their functions?
3. Which part of the nervous system controls involuntary reflexes?

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The skeleton is your body’s internal supporting structure. It holds everything together. In addition to providing support, bones act as shock absorbers when you jump, fall, and run. Bones have big responsibilities and so they must be really strong. They also need to be arranged properly for the best support and shock absorption.

In this experiment, we will look at the internal arrangement of the bones holding together your body.

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Here’s what you need

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

Download Student Worksheet & Exercises

Here’s what you do

1. First you will explore different bone structures. Start by taking 20 skinny straws and arrange them randomly in your hand so that they are pointing in different directions.
2. Lay your arm and hand on a table so that it is braced. Next, have a friend place a heavy book on this column of straws. What happens then it’s exposed to the weight?
3. Now take 20 more straws and arrange in a circle so that they are all held vertically in your hand.
4. Repeat step 2 with these more organized straws. Do you notice a difference? The uniformly arranged straws should be stronger than those that were randomly arranged.
5. The tubes inside your bones are more like the uniform model of straws. They also have a kind of glue that hold them in place inside the bones. Let’s incorporate this idea into your model by lining the inside of the toilet paper tube with tape.
6. Next, add some straws inside the tube as well. Add a single layer of straws, then another layer on top of it. Finally, fill the middle of the tube with straws, making sure they are tightly packed.
7. Test your model’s strength by placing a book on top of the tube. What happens when the model is exposed to the book’s weight?
8. For an extra study opportunity, visit the butcher in your local grocery store and ask for the end of a beef bone. (This is sometimes packaged as a soup bone). Look at the end of the bone. What do you see? It should look like a hard outer shell of bone protecting a softer, spongy portion. Draw a picture of your observations.

What’s going on?

In your experiment, it should have been readily apparent that the more organized and uniform straws were much stronger than the randomly arranged ones. Your own bones have a similar pattern in their soft, spongy part called cancellous bone. This portion of bone has a honeycombed structure which makes the bones very strong, but relatively light.  The tiny tubes that make up the honeycomb are called the Haversian system and the actual tissue of the structures is made up of collagen. This allows them to maintain flexibility, but they are still composed of minerals – notably calcium and phosphorus which give them their hardness and strength.

Exercises

1. Name some of the parts that make up our skeletal system.
2. What is the smooth, hard, protective layer on the outside of bones called?
3. What is the inside spongy, porous, honeycombed bone called?
4. What is the network of tubes inside bones called?

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Some groups of muscles are stronger than others because each group is designed for a different and specific function. It just makes sense that the muscle groups in our legs would need to be stronger than the ones in our toes.

For this experiment, you will use a bathroom scale to test the strength of various muscle groups.

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Here’s what you need

• 1 bathroom scale
• 1 pencil
• 1 partner

Download Student Worksheet & Exercises

Here’s what you do

1. Put the scale between your knees. Now squeeze it as hard as you can and have your partner record the scale’s reading.
2. Use the technique to test the muscles in the following list. Place the scale between the body parts and squeeze! Be sure to record the readings for data-keeping purposes.

a. thighs

b. ankles

c. palms

d. elbows

e. elbow and rib cage

What’s going on?

Not all muscles need to be big and powerful. Actually, muscles have various functions and uses that vary by their design. The muscles in our fingers are detail-oriented. They need to be fast and perform relatively small, precise movements like the ones used in writing. The design of a specific muscle group will vary depending upon the muscles’ ultimate use.

Have you even had a muscle cramp? They occur when a muscle is overworked and fatigued. The muscle simply contracts and stays contracted. Not fun!

Exercises

1. What are the two main types of muscles?
2. Give an example of a muscle group that’s more specific than your answers above.
3. Why aren’t the muscles in our fingers big and strong like those in our arms and legs?

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In this experiment, we will continue to explore Ruffini’s endings in your skin. We also look at your body’s ability to detect temperature and regulate its own temperature. You will study how the body cools and warms itself.

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Here’s what you need

1. 1 bottle of rubbing alcohol
2. 1 cotton ball
3. 1 liquid crystal thermometer strip
4. 1 cotton glove

Download Student Worksheet & Exercises

Here’s what you do

1. Position the thermometer strip on the back of your hand. Give it a moment to register the temperature of your body. Record this temperature as a base reading for your data.
2. Put some rubbing alcohol on a cotton ball. Now use the cotton ball to wipe the alcohol on the surface where you took the reading, right on the back of your hand. Quickly put the thermometer strip right back on the spot where you have put the alcohol and take another reading. Note the temperature in your records.
3. Now put the glove on your hand and run around in the yard, do some jumping jacks, or find another way to be physically active for 3 minutes. When you have worked up a sweat, come back to the experiment area. With your hand still in the glove, put the liquid crystal thermometer on the back of your hand where you took the first reading. Record this temperature information in your data records.
4. Finally, take off the glove and observe your hand. Can you tell that your sweat glands have been working? If so, have they been very active or just a little active?

What’s going on?

Your body likes to keep your temperature in equilibrium, which is a state of balance. It works hard to regulate your temperature and avoid any sudden changes that could be harmful. Constant and predictable is your body’s goal and it uses your skin to help.

When you are cold, blood flow to the skin is reduced in order to help stem the loss of heat. Your hair also stands on end in an error to trap air next to the body and help insulate it…although this doesn’t work very well for most of us! This is a more effective tool against heat loss with much furrier mammals.

In order to cool you down, skin can use some of your three million sweat glands. Sweat absorbs and displaces extra heat and can also close openings to cells on the surface to avoid excess gains in heat.

Your data in the lab should have simulated the effects of body temperature in three different conditions: equilibrium, excess cold, and excess heat.

Exercises

1. What is equilibrium?
2. How does equilibrium relate to body temperature?
3. How does our body help to cool us down?

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Your fingers have receptors which perform various jobs. In addition to touch, they can detect pressure, texture, and other physical stimuli.  One specialized type of receptors is called Ruffini’s receptors. They are good at identifying changes in pressure and temperature. In this experiment, we will test their ability to distinguish between hot and cold temperatures. We are actually going to try and trick your Ruffini endings. Do you think it will work?

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Here’s what you need

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

Download Student Worksheet & Exercises

Here’s what you do

1. Place the three glasses in front of you on a table. They should be in a row: left, middle and right.
2. Put hot water from the faucet into the first glass on your right. Pour very cold water from the tap into the far left glass. You can even add a couple of ice cubes if you have them available. Finally, fill the glass that is in the middle with room temperature water.
3. Now use your right hand to hold on to the glass on the right with hot water. Really spread out your fingers and wrap them around the glass. Do the same thing with your left hand and the glass filled with cold water. Be sure to check the clock and leave your hands on the glasses for exactly one minute.
4. After one minute, take your hands and put them both on the middle glass. (You may need to stack one on top of the other if your glasses are narrow). Note the temperature you feel with each hand: hot, cold, or medium. You can use the thermometer to record the actual water temperature.
5. Now repeat steps 1-4. This time, switch the hot and cold glasses so that you are holding the hot water with your left hand and the cold water with your right hand. Compare these results with your initial results. Do both hands respond in a similar way or is one more sensitive that the other?
6. Some questions to think about:

Does the temperature of the middle glass feel warmer, cooler, or the same when you touch it with your hand that was holding the warm glass?
What does your hand that was touching the cold glass feel when it touches the middle glass?
What do you feel when both hands are on the middle glass?
Why do you think your hands are not the best instruments for determining temperature?

 What’s going on?

Your hands are designed to adapt to temperature. Touching the warm glass relaxes the muscles of your hands, increases circulation, and enhances flexibility. When your hand touches the cold glass the cells on your skin’s surface begin to contract to minimize loss of heat and your hand becomes less flexible. Then, when you grab the middle can your hands get a bit confused. Relatively speaking, the middle glass feels warmer to the hand that was holding the cold glass and it feels cooler to the hand that was holding the warm one. The hands are still feeling the temperature, but your brain gets confused.

Did you know that our skin does not have receptors to indicated burning hot? This sensation is actually created by three different receptors which fire at the same time: pain, cold, and warm. This explain why to some people, very hot things actually feel cold. If you could prepare a group of alternating hot and cold metal bars, touching them with your fingers would be an odd experience. Your brain will think they are too hot to touch and will tell you to pull away your hand!

Exercises

1. Does the temperature of the middle glass feel warmer, cooler, or the same when you touch it with your hand that was holding the warm glass?
2. What does your hand that was touching the cold glass feel when it touches the middle glass?
3. What do you feel when both hands are on the middle glass?
4. Why do you think your hands are not the best instruments for determining temperature?
5. Which nerve endings help to detect changes in temperature?

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Skin has another function that it vital to your survival: temperature regulation. Being exposed to high temperatures causes your skin’s pores to open up and release sweat onto your body. This helps cool us off by the resulting process of evaporation.

Your pores will close in extremely cold temperatures. Also, the body stops blood flowing to the skin in order to conserve heat for the important vital organs and their processes.

In this lab, we study the moisture that your skin produces – even when you are not aware of it!

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Here’s what you need

• 1 gallon baggie
• 1 string, 12 inches long
• 1 assistant
• 1 clock

Download Student Worksheet & Exercises

Here’s what you do

1. Record a description of how moist your hand is prior to putting it in the baggie. This is at 0 minutes.
2. Put your hand in the baggie and ask your assistant to tie it closed around your wrist. No air should be able to get in or out of the baggie. Record the time for tracking purposes.
3. Check your hand every 10 minutes for a half hour. With each observation note the amount of moisture that has accumulated. Record your observations at 10 minutes, 20 minutes, and 30 minutes.
4. What do you think will happen if you go outside and run around with your hand inside the bag? Try it and see if it accelerates the process.

What’s going on?

Sweat glands are always producing moisture on our skin. Most of the time, we don’t really notice this process. By enclosing your hand in plastic, this moisture can’t evaporate as it normally would. The bag collects and condenses it.

It is interesting to note that your body can produce up to a gallon of water in extremely hot temperatures – 110 degrees Fahrenheit and higher. This is one of the reasons it’s so important to stay hydrated in extreme heat!

Exercises

1. How is sweat released from the body through the skin?
2. How does sweat help to cool the body?
3. What did you observe at the 30 minute mark in your experiment?
4. What is evaporation and how is it different from condensation?

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This lab has two parts. First, you will learn a bit about how specific chemicals react in a specific manner. And next, you will learn a bit of biology: the structure of bird bones and the minerals that compose them.

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Here’s what you need

• 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

Here’s what you do

1. Make sure all the meat and cartilage is gone. Check near the joints for soft, white-gray matter and clean it off. Now break a bone in half. What does the inside look like? Note the color and hardness for your data. Be sure to wash your hands well after studying the bones.
2. Pour some vinegar in a cup and gently place the bones in the solution. Add more to cover the bones, if needed. Put the cup in a spot where it won’t be disturbed for a few days. It will take a while for the vinegar to fully react with the bones.
3. Take a look at the egg and note its color and hardness in your experiment data. Now carefully place the fresh egg in the second cup and pour vinegar over it. Be sure to completely cover the egg. You will need to cover the egg or keep an eye on it. The vinegar will evaporate and will need to be replenished. This portion of the experiment will take around 24 hours.
4. Use the spoon to remove the egg after 24 hours has passed. Set it down and gently push on it. What happened to the part that used to be shell? Check your notes from the previous day and note any changes that have occurred in the color and hardness of the egg after it has been in the vinegar.
5. After a few more days, take the chicken bones out of the vinegar. Bend them and see what happens. Do they break as easily as they did the first day? Look at your data and compare the color and hardness of the bones now to how they looked on the first day. Record the changes you observe.

What’s going on?

Calcium is the mineral in both bones and eggshells that makes them hard.  Putting the bones and egg in vinegar caused the calcium to begin to react. Vinegar leached calcium from both the bones and the shell, which caused their hardened structure to become weak.

Did you know that your bones and teeth contain 99% of the calcium in your body? About ¾ of your bones are compact, but the remaining ¼ of them is spongy. But do you think your bones or your teeth are harder? The second hardest material in your entire body is the compact, hard bone. Your teeth enamel is actually the hardest material.

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This experiment has two parts. For the first half, you will mix two chemicals that will produce heat and gas. The temperature receptors in your skin will be able to detect the heat. Your ears will detect the gas at it vibrates and escapes its container.

In the second portion you will demonstrate a characteristic in a chemical reaction. For this experiment, it will be an endothermic reaction, which is the absorption of heat energy. This type of reaction is easy to notice because it makes things cold to touch.  The chemical you will be using, ammonium nitrate, is actually used in emergency cold packs.

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Here’s what you need

• 1 measuring cup
• 1 bottle of calcium chloride
• 1 bottle of ammonium nitrate
• 2 resealable baggies
• water

Download Student Worksheet & Exercises

Here’s what you do

1. Put about ½ cup of warm water in one of the baggies.
2. Add about a third of an ounce of calcium chloride to the water. Close the baggie and start to roll around the pellets with your fingers. As they start to dissolve, the chemical also starts to increase the temperature of the water.
3. Now dispose of these ingredients down the drain. Flush with lots of running water.
4. Open the ammonium nitrate and fill its cap with pellets. Put these in the second baggie.
5. Start to pinch the ammonium nitrate through the plastic bag and check for a temperature change. Does anything happen in the absence of water?
6. Now put a small amount of water (about room temperature) into the bag. Fill it about ¼ of the way full.
7. Hold the bottom of the bag with both hands and begin to rock it back and forth a bit. This should start to dissolve the pellets. With your hands on the water, you should start to note a temperature decrease. If this doesn’t work, roll the pellets around as you did with the calcium chloride.
8. When you are finished, you can pour the contents out on to brown spot of grass (because ammonium nitrate is a main ingredient in many fertilizers). Or if you would prefer, just empty the contents down the drain.

What’s going on?

Calcium chloride splits into calcium ions and chloride ions when it is mixed with water. As this occurs, energy is released in the form of heat. This is the same heat energy you felt when holding the baggie and rubbing the pellets.

Adding ammonium nitrate to water causes both its ammonium and nitrate ions to dissolve, which results in heat absorption as iconic bonds are broken. This is an endothermic reaction.

The point of both of these experiments is that the Ruffini’s endings in your skin are what allow the heat and/or cold data to be collected and sent to your brain for translation.

Your skin has many other parts in addition to its receptors. Some examples include hair, blood vessels, and sweat glands. Blood vessels and sweat glands respond to heat and cold, helping to control your body’s temperature. You are probably familiar with how sweat glands help to cool you down (evaporation), but how about blood vessels?  As an example,  if you run around outside on a hot day, your cheeks get red  because the blood vessels on your skin’s surface have dilated, which brings more blood to the surface and allows the body to cool its insides a bit.

Exercises

1. Which chemical when mixed with water was an endothermic (absorbed heat and felt cold) reaction?
2. Which chemical resulted in an exothermic reaction (gave off heat)? Why does this happen?
3. What are ways that the human body can detect temperature?

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In addition to looking pretty neat with all those loops and whirls, your fingertips are great at multitasking. The skin on them has a ton of receptors that help us to gather a lot of information about our environment such as texture, movement, pressure, and temperature.

This experiment will test your ability to determine textures by using touch receptors. You will use shoeboxes with holes cut into them to make texture boxes. Each box will have a textured surface that you can feel, but not see. Through the receptors in your fingers, you will determine whether the surface is rough, waxy, soft, or smooth.

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Here’s what you need

• 4 shoeboxes with lids
• 1 soup can
• 1 pencil
• 1 pair of scissors
• 1 sheet of sandpaper
• 1 sheet of wax paper
• 1 sheet of flannel fabric
• 1 sheet of plastic
• 1 glue gun
• 1 pair of gloves
• partners

Download Student Worksheet & Exercises

Here’s what you do

1. Using the soup can as a guide, draw a circle at the end of a shoebox.  Then use the scissors to cut out the circle.
2. Cut a piece of sandpaper to fit the bottom of the shoebox (a ruler might also be handy to get an exact measurement). Glue the sandpaper to the inside bottom of the shoebox. Put the lid on the box and label it as Box 1.
3. Repeat the first two steps for each of the boxes, putting the wax paper, flannel, and plastic in boxes 2-4. Be sure to label each.
4. Now ask a partner to reach into each box, feel the texture, and describe it as rough, waxy, soft, or smooth. Record their answer. Use undecided if they aren’t sure.
5. Once your friend has identified a texture and you have recorded their response, open the box so that you can both see what material they have evaluated. Be sure to note in your data whether your friend was correct with a Y or N. Repeat steps 4 and 5 for each of the boxes.
6. Have your friend leave the room or look away so that you can rearrange the box lids. Then give them the gloves to wear and repeat the test using gloved hands. Record the data and compare the effectiveness of gloved hands. Does this have an impact on the touch receptors?

What’s going on?

The fabric of the gloves interferes with the ability of our touch receptors to function fully. Our fingertips are feeling the fabric of the gloves on their receptors and this makes it difficult to perceive what they are touching through the gloves.

We have 5 different types of receptors. They are types of nerve endings in our skin and are connected to our brains.

• The ones that respond to deep pressure are called Pacini’s endings and they are embedded deep in our skin.
• Merkel’s endings detect moderate pressure.
• Meissner’s ending respond to vibrations and light pressure.
• Ruffini’s ending, which detect changes in temperature, can also respond to pressure.
• Our pain receptors are called free endings.

Exercises

1. Name, in order, the three main layers of skin.
2. Which layer of skin contains the mechanoreceptors? Name two more items in this layer.
3. Name the five types of nerve endings and their specialization.

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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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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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A pedigree analysis chart, usually used for families, allow us to visualize the inheritance of genotypes and phenotypes (traits). In this chart, the P, F1, and F2 generation are represented by the numerals I, II, and III respectively. Notice that those carrying the trait are colored red, and those not carrying the trait (the normal-looking ones) are in blue. The normal, non-trait carrying organisms on the chart are called the wild-type.

The term wild-type is used in genetics often to refer to organisms not carrying the trait being studied. For example, if we were studying a gene that turns house-flies orange, we would call the normal-looking ones the wild-type.

Let’s make a pedigree for your family. Here’s what you need:

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Materials:
• Paper
• Pen
• Access to a photocopier (optional)

To start this project, draw a pedigree showing the different members of your family.

a. Include as many family members as you can get data from. The more people and generations you include, the more likely it is that you’ll have enough information to determine the mode of inheritance.

b. You might need help from your parents to figure out all the relationships.

2. If you have access to a photocopier, make four copies of the pedigree—one for each trait you are going to evaluate. If photocopying isn’t an option, manually copy the pedigree.

3. Determine the phenotype of each person on your pedigree for each of the four traits. Use a separate pedigree for each trait. Examples are: eye-color, hair color, widow’s peak, height. Note: Widow’s peak can vary considerably; score any sort of V-shaped hairline as positive.

4. From your pedigrees, can you deduce the mode of inheritance for each trait? For which traits is your pedigree informative? If you don’t have enough information to determine the mode of inheritance of a particular trait, try making a pedigree for another family.

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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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Why do families share similar features like eye and hair color? Why aren’t they exact clones of each other? These questions and many more will be answered as well look into the fascinating world of genetics!

Genetics asks which features are passed on from generation to generation in living things. It also tries to explain how those features are passed on (or not passed on). Which features are stay and leave depend on the genes of the organism and the environment the organism lives in. Genes are the “inheritance factors “described in Mendel’s laws. The genes are passed on from generation to generation and instruct the cell how to make proteins. A genotype refers to the genetic make-up of a trait, while phenotype refers to the physical manifestation of the trait.

We’re going to create a family using genetics!

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Materials
• Paper or use this Genetics Table
• Two different coins
• Scissors
• Glue or Tape

Download Student Worksheet & Exercises

Step one: Creating the Parent Generation

1. First you’re going to create the genetic make-up of the parents. Here’s how:
2. Take out the Genetics Data Table, and flip the first coin to create the genetic profile for the mother.
3. Flip the coin and in the Mother’s Hair trait column, write D for dominant if the coin reads heads, and R for recessive if tails in the table.
4. Flip the coin again. In the Mother’s Hair trait column right after the first trait, write D for dominant if the coin reads heads, and R for recessive if tails in the table.
5. If you flipped heads the first time and tails the second, you’d write “DR” in the Mother’s Hair box.
6. Continue this process for all of Mother’s traits. You should have two letters in each box for the entire column.
7. Repeat steps 3-6 for Father. When you’ve completely filled out Mother’s and Father’s columns, you’ve completed the paternal genetic profile. Now you’re ready for the next part:

Step two: The Child

1. Will the child be a boy or a girl? To determine this, flip the second coin. Heads for a boy, tails for a girl. After this is decided, circle boy or girl under “child 1” on the Genetics Data Table.
2. Now the first coin will represent the gene from the mother and the second coin will represent the gene from the father.
3. Start with the Hair trait: Flip both coins. If the first coin is tails, take the first trait from the mother. If the first coin is heads, take the second trait.
   1. For example, if the first coin is tails, and the mother’s code is DR, then write “D” in the child one column for hair.
   2. Do the same thing for the father’s traits with the second coin. For example, if the second coin is heads, and the father’s code is DR, then write “R” in the Hair Trait column of child 1.
   3. By the end of this step, child 1 should have one letter from the mother, and one letter for the father in child 1’s hair trait column.
4. Use the same steps used to find the genetic code for the hair trait to find the code for the rest of the traits. By the end all the traits should have one letter from the mother’s genetic code and one letter from the father’s genetic code.

Step 3: What the Child Looks Like

Grab a sheet of paper and start drawing the child. If the genetic code for a trait has a “D” in it, then the dominant trait is used.

For example, if the hair color is DD, DR, or RD then the hair color is dark. If the hair color code is RR, then the hair color is light. Draw the traits on your paper!

You can repeat this for as many children as you would like in your family.

Step 4: Make another family and compare!

Are all families alike? What if you try this process again for another family? Do you see any similarities or differences? Do similar features come from dominant genes? Do differences come from recessive genes? What other traits would you include? Write this in your science journal!

Conclusions:

In fact, most similarities should come from the dominant genes because they are expressed more often. The recessive genes are expressed less often, so the create the differences.

Extra credit:

What percent of the children expressed the dominant allele of each trait? Did you get Mendel’s results? Do the calculations and check it out!

Exercises

1. What is the difference between a genotype and a phenotype?
2. What is a dominant trait?
3. What is a recessive trait?
4. Assume B=Black hair and b=blond hair.  Make a Punnet square to cross Bb with bb. Tell what the possibilities are for offspring hair color.
5. Why don’t traits simply average out in offspring.  For example, why does a tall plant crossed with a short plant not yield a bunch of average-sized plants?
6. In your activity, what percent of the children expressed the dominant allele of each trait? Did you get Mendel’s results? Do the calculations and check it out!

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Plants need light, water, and soil to grow. If you provide those things, you can make your own greenhouse where you can easily observe plants growing. Here’s a simple experiment on how to use the stuff from your recycling bin to make your own garden greenhouse.

We’ll first look at how to make a standard, ordinary greenhouse. Once your plants start to grow, use the second part of this experiment to track your plant growth. Once you’ve got the hang of how to make a bottle garden, then you can try growing a carnivorous greenhouse.
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Materials:

• 2 liter bottle
• scissors or razor
• gravel or sand
• spanish moss
• dish or plate
• seeds of your choice

Experiment:

1. Using an exacto knife or scissors, cut the label from the soda bottle. Carefully cut the bottle in half so that the bottom (container) piece is deep enough to hold soil and plants. Poke a few holes into the bottom of the container for drainage.
2. Fill the bottom of the bottle with a half cup of sand or gravel to provide drainage. Use playground sand, aquarium gravel or small stones picked up from a hike. If sand or gravel isn’t available, crush an old clay pot and use that. (Let an adult crush the pot.)
3. Place a 1-inch layer of Spanish or Spaghnum moss in the mini greenhouse to keep the soil from mixing with the rock layer. Place a thick layer of potting soil on top of the moss, at least 4 inches deep or 1 inch from the top. Tamp down lightly with your finger
4. Put the top half of the soda bottle back on, tucking inside the edges of the container. If necessary, you can cut small slits into the upper portion to make it fit. Leave the cap on.
5. Place atop a waterproof plate in a sunny spot and water sparingly. The lid retains moisture and heat, so your seeds should sprout quickly. Because the plastic is clear, you’ll be able to see the roots beneath the surface of the soil. If the greenhouse gets too steamy, you can remove the lid once in a while. When your seedlings get big enough, transplant to the garden, and plant a new crop!

Tracking Plant Growth

You know that plants grow… but when a plant grows, is the entire stem getting longer, like rolling dough, or is only the tip growing, like squeezing the end of a toothpaste tube?

This simple experiment can give you the answer. Ready?

1. Tie string around the edge of a plants stem, between the last leaf at the end, and the next leaf.
2. Make observations as the plant grows.

What’s going on? If the entire stem grows, your string will always stay at the end. If just the tip grows, the string will become further and further from the edge. Which is it? Are you surprised?

Carnivorous Greenhouse

Was the last activity too tame for you? You’ll need to order carnivorous plant seeds. Carnivorous plants are heterotrophs. As you learned, this means they must get their energy from other organisms instead of the sun. Such plants are good at catching small animals, such as insects, to eat. Used the video below to learn how to plant the seeds that will produce these carnivores, and how to care for them once they have sprouted.

Download Student Worksheet & Exercises

Exercises

1. What is a carnivorous plant?
2.  What is another name for a carnivorous plant?
3.  What does a carnivorous plant need to thrive?
4.  Should we fertilize a carnivorous plant? Why or why not?

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As you walk around your neighborhood, you probably see many other people, as well as some birds flying around, maybe some fish swimming down a local stream, and perhaps even a lizard darting behind a bush or a frog sitting contently on top of a pond. Most likely, you know that all of these living things are animals, but they are even more closely related than that.

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Tide pools are best observed undisturbed. But, they’re too shallow to snorkel… So how to can we explore them without removing their inhabitants? With an Aquascope! Aquascopes are very cheap and easy to make. With only a coffee can, some plastic food rap, and a couple of other items you can make a window into the world of tide-pools! In principle, aquascopes allow us to take a glass-bottom-boat tour of the rich ecosystems of tide pools. The plastic acts as the glass, while the coffee can allows us to break the distorting surface of the water.

Here’s a video to get you started:

Download Student Worksheet & Exercises

Here’s what you need:

• milk or juice jug
• plastic wrap
• scissors
• rubber band

Here’s the steps to make the waterscope:

1. Clean out your jug first. Then cut the bottom and top off without cutting off the handle.
2. Cover the opening at the bottom with your plastic wrap, securing it in place with the rubber band. Use tape if you need extra support to hold the plastic wrap in place. The window needs to be water-tight.
3. Place the waterscope in the water, bottom-side down. You’ll be able to see all kinds of interesting creatures through your scope!
4. Try to keep your scope still so the animals won’t be afraid to come close to you so you can have a good peek at their world.   The aquascope works the same way snorkel goggles work—except you don’t have to get wet!

Why this works: You can’t see clearly underwater with just your eyes for a couple of reasons. One is the thickness of the lens on your eye, but the main one is the index of refraction of water is different than that of air. Light rays bend when they travel from one medium to another of different density (refer to the Disappearing Beaker experiment for more on this topic). The amount that the light bends depends on refractive index of each substance along with the shape. The eye focuses images on the retina, and our eyes are built for viewing in air. Water has approximately the same refractive index as the cornea which effectively eliminating the cornea’s focusing properties. This is why you see a blurred image underwater. The eyes are focusing the image them far behind the retina instead of on the retina. The waterscope puts a layer of air between your eyes and the water (the same way goggles do) so you can view underwater without blurred vision.

Troubleshooting: The key to the aquascope is the taught plastic wrap. If it’s loose, or if there are holes, it won’t work as well. Make sure that the plastic wrap is securely fastened to the can, and is stretched tight. If you find your waterscope leaks, use a stronger rubber band to secure your plastic wrap in place. You can alternatively use strong waterproof tape or hot glue to secure it in place, but use the rubber band first so you can stretch the film tightly over the open end.

Exercises

1. What is the term for light rays bending?
2. Why is underwater vision blurred?
3. How can we focus vision underwater?

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Unsurprisingly, often the most interesting critters found in soil are the hardest to find! They’re small, fast, and used to avoiding things that search for them. So, how do we find and study these tiny insects? With a Berlese Funnel (Also called the Tullgren funnel)!

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The funnel separates the insects from the soil with heat. A light bulb heats the soil at one end of a funnel and causes the insects to migrate, through mesh, to a preservative liquid at the other end of the funnel. Originally Antonio Berlese used a hot water bottle to provide the heat. Later, Albert Tullgren modified the funnel to work with a light bulb. Thus, we now call it the Berlese Funnel, the Tullgren Funnel, or the Berlese-Tullgren Funnel.

Download Student Worksheet & Exercises

An ultraviolet lamp used to attract night flying insects. The simplest set up is to hang a white sheet on a line and hang a portable black light on one side of the sheet. Insects will land on the sheet and can be tallied, identified or collected.

To make a larger, more permanent model, here’s what you need:

• 1 gallon tractor funnel.
• Clothespins.
• A light fixture that fits on top of the funnel and has a reflective interior.
• A bucket that has a smaller diameter than the top of the funnel. The funnel needs to be suspended from the bucket so the insects can fall into the jar.
• A clean jam-jar.
• Rubbing alcohol.
• ¼ inch wire mesh.
• Light bulb. The wattage has to be high enough to heat the soil, but not so high that it will light the funnel on fire. Best to do it by trial and error with lots of supervision.
• Soil. The best will be from a compost pile.

Here’s how you make the funnel:

1. Cut a large hole in the side of the bucket. This will allow you to retrieve the jar without disassembling the apparatus. Naturally, the hole should be larger than the jar.
2. Fit the wire mesh so that it covers the bottom third of the funnel.
3. Fit the funnel on top of the bucket.
4. Fit the light fixture (with the light bulb in it) on top of the funnel with the clothespin.
5.  Place the jar underneath the funnel (with or without the rubbing alcohol depending on if you want the specimens dead or alive).

How to use the funnel: Simply turn on the light and wait. Check the vial every fifteen minutes or so for an hour. After you have finished remember to turn off the light! Also, remember that some of the specimens may be very small and best observed under a microscope. For the best results do it in the morning or on a cold day.

How the funnel works:  Figure 1 shows the funnel in action. The light (G) creates heat. The insects in the soil don’t like heat, so they move from the soil (D) through the funnel (C) into the jar (B). The jar is filled with rubbing alcohol (A) preserves the specimens. The wire (not shown in the figure) keeps most of the soil from falling into the jar.

Troubleshooting: What if there still aren’t any bugs after an hour? If this happens, don’t panic. Ask yourself these questions:

• Is the light strong enough? If the light is not strong enough (i.e. generating enough heat), then the soil will not get hot enough to push the insects into the jar. The funnel works by creating a gradient of heat which the bugs move down into the jar. If the light isn’t creating that gradient, no critters will feel like moving.
• Is it hot today? If the sun is out and making everything hot, then the light will not make enough of a difference in heat—there will not be a heat gradient to move down. If so, don’t worry; just try again the next morning.
• Is there a problem with the funnel? Is the nozzle of the funnel too far from the mouth of the jar? Make sure that the specimens are falling into the jar and not around it. Is the mesh wire too fine? You want mesh that will keep most of the soil in the funnel, but not so fine that it will stop the bugs from getting through.
• Lastly, are there any bugs in the soil? Not just any dirt will do for this project. You need soil rich with life! The best place to find this type of soil is near/in a compost pile (after it has become soil).

Exercises

1. Why are some insects difficult to find in soil?
2.  Why does the Berlese Funnel work to find insects?
3.  What if the insects do not respond to the heat lamp in your experiment?
4.  What types of insects were you able to find using the Funnel?

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Some insects are just too small! Even if we try to carefully pick them up with forceps, they either escape or are crushed. What to do?

Answer: Make an insect aspirator! An insect aspirator is a simple tool scientists use to collect bugs and insects that are too small to be picked up manually. Basically it’s a mini bug vacuum!

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Download Student Worksheet & Exercises

Here’s what we’ll need:

• A small vial or test tube with a (snug fitting) two-holed rubber stopper.
• Two short pieces of stiff plastic tubing. We’ll call them tube A and tube B.
• Fine wire mesh (very small holes because this is what will stop the bugs from going into your mouth!)
• A cotton ball.
• One to two feet of flexible rubber tubing.
• Duct tape or a rubber band.

Here’s how we make it:

• Insert the tube A and Tube B into the stopper such that the stopper is in the middle of both pieces.
• Bend both A and B plastic tubing 90 degrees away from each other. Their ends should be pointing away from each other.
• Cut a square of mesh large enough to the end of the plastic tubing. Tape (or rubber-band) the mesh over bottom of tube A only. Remember, if you cover both of the tubes the bugs won’t be able to enter the aspirator.
• Insert a small amount of cotton ball into the other side of tube A (not enough to block airflow, just enough to help filter the dust and particles entering the vial.
• Cut another piece of mesh and cover the other end of Tube A. Secure that mesh with another piece of tape/rubber band.
•  Fit the rubber tubing over the top of tube B (the bent side).
• Fit the stopper into the vial/test tube.

How it works: To use the aspirator, hold the end of the rubber tubing near the insects you want to collect, and suck through the top of tube A. The vacuum you create sucks the insects into the vial/test tub (make sure they can fit in the tube!).

Troubleshooting: The bugs aren’t being pulled into the vial! In that case the suction may not be strong enough. Remove the cotton ball and try again. If it still is not working check to make sure the aspirator is air-tight (is the stopper fitting snuggly into the vial? Are there cracks/holes around or in the plastic tubes?).

TIP: I kept eating bugs! Make sure your wire mesh is very fine (the holes are smaller than the bugs you’re trying to collect). Otherwise you may be ordering a lunch you don’t want!

Exercises

1. Why don’t we use a large vacuum to suck up the bugs?
2.  Why do we need a small mesh covering on the end of the straw that we suck on?
3.  Why do we need to be careful about catching ants?
4.  What insects did you catch that you rarely see?
5.  What familiar insects did you catch? (answers may vary).

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The way animals and plants behave is so complicated because it not only depends on climate, water availability, competition for resources, nutrients available, and disease presence but also having the patience and ability to study them close-up.

We’re going to build an eco-system where you’ll farm prey stock for the predators so you’ll be able to view their behavior. You’ll also get a chance to watch both of them feed, hatch, molt, and more! You’ll observe closely the two different organisms and learn all about the way they live, eat, and are eaten.

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This experiment comes in two parts. The materials you need for both parts are:

• four 2-liter soda bottles, empty and clean
• 2 bottle caps
• one plastic lid that fits inside the soda bottle
• small piece of fruit to feed fruit flies
• aluminum foil
• plastic container with a snap-lid (like an M&M container or film can)
• scissors and razor with adult help
• tape
• ruler
• predators: spiders OR praying mantis OR carnivorous plants (if you’re using carnivorous plants, make sure you do this Carnivorous Greenhouse experiment first so you know how to grow them successfully)
• soil, twigs, small plants

Fruit Fly Trap

In order to build this experiment, you first need prey. We’re going to make a fruit fly trap to start your prey farm, and once this is established, then you can build the predator column. Here’s what you need to do to build the prey farm:

Download Student Worksheet & Exercises

Did you know that fruit flies don’t really eat fruit? They actually eat the yeast that growing on the fruit. Fruit flies actually bring the yeast with them on the pads of their feet and spread the yeast to the fruit so that they can eat it. You can tell if a fruit fly has been on your fuit because yeast has begun to spread on the skin.

When you have enough fruit flies to transfer to the predator-prey column, put the entire fruit fly trap in the refrigerator for a half hour to slow the flies down so you can move them.

If you find you’ve got way too many fruit flies, you might want to trap them instead of breed them. Remove the foil buckets every 4-7 days or when you see larvae on the fruit, and replace with fresh ones and toss the fruit away. Don’t toss the larvae in the trash, or you’ll never get rid of them from your trash area! Put them down the drain with plenty of water.

Predator-Prey Column

You can use carnivorous plants, small spiders, or praying mantises. If you use plants, choose venus flytraps, sundews, or butterworts and make sure your soil is boggy and acidic. You can add a bit of activated charcoal to the soil if you need to change the pH. Since the plants like warm, humid environments, keep the soil moist enough for water to fog up the inside on a regular basis. You know you’ve got too much moisture inside if you find algae on the plants and dirt. (If this happens, poke a couple of air holes.) Don’t forget to only use distilled water for the carnivorous plants!

Keep the column out of direct sunlight so you don’t cook your plants and animals.

Exercises

1. What shape is the head of the mantis?
2.  How many eyes does a praying mantis have?
3.  How else has the mantis head evolved to stalk their prey?
4.  How does a praying mantis hold its food?
5.  Do fruit flies eat fruit?
6.  How do predators and prey change over time?

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How does salt affect plant growth, like when we use salt to de-ice snowy winter roads? How does adding fertilizer to the soil help or hurt the plants? What type of soil best purifies the water? All these questions and more can be answered by building a terrarium-aquarium system to discover how these systems are connected together.

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Here’s what you need:

• two 2-liter soda bottles, empty and clean
• two bottle caps
• scissors and razor with adult help
• tape
• water, soil, and plants

Here’s what you do:

Download Student Worksheet & Exercises

Water drips off the roof of your house, down your driveway, over your toothbrush and down the sink, through farm fields, and into rivers, lakes and oceans. While traveling, this water picks up litter, nutrients, salts, oil, and also gets purified by running through soil. All of this has an affect on fish and animals that live in the oceans. The question is, how does it affect the marine ecosystem? That’s what this experiment will help you discover.

Land and aquatic plants are excellent indicators of changes in your terraqua system. By using fast-germinating plats, you’ll see the changes in a relatively short about of time. You can also try grass seeds (lawn mixes are good, too), as well as radishes and beans. Pick seeds that have a life cycle of less than 45 days.

How to Care for your TAC (Terra-Aqua Column) EcoSystem:

1. Keep the TAC out of direct sunlight.
2. Keep your cotton ball very wet using only distilled water. Your plants and triops are very sensitive to the kind of water you use.
3. Feed your triops once they hatch (see below for instructions)
4. Keep an eye on plant and algae growth  (see below for tips)

About the plants and animals in your TAC:

1. Carnivorous plans are easy to grow in your TAC, as they prefer warm, boggy conditions, so here are a few tips: keep the TAC out of direct sunlight but in a well-lit room. Water should condense on the sides of the column, but if lots of black algae start growing on the soil and leaves, poke more air holes! Water your soil with distilled water, or you will burn the roots of your carnivorous plants.  Trim your plants if they crowd your TAC.
2. If you run out of fruit flies, place a few slices of banana or melon in an aluminum cup or milk jig lid at the bottom of a soda bottle (which has the top half cut off). Invert the top half and place it upside down into the bottom part so it looks like a funnel and seal with tape so the flies can’t escape.  Make a hole in the cap small enough so only one fly can get through. The speed of a fruit fly’s life cycle (10-14 days) depends on the temperature range (75-80 degrees). Transfer the flies to your TAC. If you have too many fruit flies, discard the fruit by putting it outside (away from your trash cans) or flush it down the toilet.
3. You can’t feed a praying mantis too much, and they must have water at all times. You can place 2-3 baby mantises in a TAC at one time with the fruit flies breeding below. When a mantis molts, it can get eaten by live crickets, so don’t feed if you see it begin to molt. When you see wings develop, they are done fully mature. Adult mantises will need crickets, houseflies, and roaches in addition to fruit flies.
4. Baby triops will hatch in your TAC aquarium. The first day they do not need food. Crush a green and brown pellet and mix together. Feed your triop half of this mixture on the 2^nd and the other half on the 4^th day (no food on day 3). After a week, feed one pellet per day, alternating between green and brown pellets. You can also feed them shredded carrot or brine shrimp to grow them larger. If you need to add water (or if the water is too muddy), you can replace half the water with fresh, room temperature distilled water. You can add glowing beads when your triop is 5 days old so you can see them swimming at night (poke these through the access hole).

Exercises

1.  What three things do plants need to survive?
2.  What two things do animals need to survive?
3.  Does salt affect plants? How?

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What grows in the corner of your windowsill? In the cracks in the sidewalk? Under the front steps? In the gutter at the bottom of the driveway? Specifically, how  doe these animals build their homes and how much space do they need? What do they eat? Where do fish get their food? How do ants find their next meal?

These are hard questions to answer if you don’t have a chance to observe these animals up-close. By building an eco-system, you’ll get to observe and investigate the habits and behaviors of your favorite animals. This column will have an aquarium section, a decomposition chamber with fruit flies or worms, and a predator chamber, with water that flows through all sections. This is a great way to see how the water cycle, insects, plants, soil, and marine animals all work together and interact.

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Here’s what you need:

• four (or more) 2-liter soda bottles, empty and clean and with caps
• scissors
• tape
• razor with adult help
• ruler
• soil
• water
• plants or seeds
• compost or organic/food scraps
• spiders, snails, fruit flies, etc

Here’s what you do:

Download Student Worksheet & Exercises

You can easily incorporate the Water Cycle Column, the Terraqua Column, the Predator-Prey Column, Worm Column, and the Fruit Fly Trap into your Eco-Column. If you want to make your Eco-Column more permanent, seal it together with silicone sealant, making sure you have enough drainage holes and air holes in the right places first.

Exercises

1. What are parts of the eco system?

2. Give an example of each.

3. What do decomposers do?

4. How do fruit flies breed?

5. How does the precipitation funnel function in this eco column?

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When birds and animals drink from lakes, rivers, and ponds, how pure it is? Are they really getting the water they need, or are they getting something else with the water?

This is a great experiment to see how water moves through natural systems. We’ll explore how water and the atmosphere are both polluted and purified, and we’ll investigate how plants and soil help with both of these. We’ll be taking advantage of capillary action by using a wick to move the water from the lower aquarium chamber into the upper soil chamber, where it will both evaporate and transpire (evaporate from the leaves of plants) and rise until it hits a cold front and condenses into rain, which falls into your collection bucket for further analysis.

Sound complicated? It really isn’t, and the best part is that it not only uses parts from your recycling bin but also takes ten minutes to make.

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Here’s what you need:

• three 2-liter soda bottles, empty and clean
• razor with adult help
• scissors
• tape
• ruler
• 60 cm heavy cotton string
• soil
• water
• ice
• plants
• drill and drill bits
• fast-growing plant seeds (radish, grass, turnips, Chinese cabbage, moss, etc.)

Here’s what you do:

Download Student Worksheet & Exercises

Make sure your wicks are thoroughly soaked before adding the soil and plants! You can either add ice cubes to the top chamber or fill it carefully with water and freeze the whole thing solid. If you’re growing plants from seeds, leave the top chamber off until they have sprouted.

You can add a strip of pH paper both inside and outside your soil chamber to test the difference in pH as you introduce different conditions. You can check out the Chemical Matrix Experiment and the Acid-Base Experiment also!) What happens if you light a match, blow it out, and then drop it in the soil chamber? (Hint – you’ve just made acid rain!)

Do you think salt travels with the water? What if you add salt to the aquarium chamber? Will it rain salty water? You can place a bit of moss in the collection bucket to indicate how pure the water is (don’t drink it – that’s never a good idea).

Exercises

1. Do you think salt travels with the water?
2. What if you add salt to the aquarium chamber? Will it rain salty water?
3. What happens if you light a match, blow it out, and then drop it in the soil chamber? (Hint – you’ve just made acid rain!)

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Mass and energy are conserved. This means you can’t create or destroy them, but you can change their location or form.

Most people don’t understand that the E energy term means all the energy transformations, not just the nuclear energy.

The energy could be burning gasoline, fusion reactions (like in the sun), metabolizing your lunch, elastic energy in a stretched rubber band… every kind of energy stored in the mass is what E stands for.

For example, if I were to stretch a rubber band and somehow weigh it in the stretched position, I would find it weighed slightly more than in the unstretched position.

Why? How can this be? I didn’t add any more particles to the system – I simply stretched the rubber band. I added energy to the system, which was stored in the electromagnetic forces inside the rubber band, which add to the mass of the object (albeit very slightly). Read more about this in Unit 7: Lesson 3.

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For plants, this means that energy from captured sunlight, combined with carbon dioxide and water, both of which have mass, make the plant heavier. Let’s find out how Einstein would have planted a garden while thinking about his big ideas.

Materials:

• scale for weighing your plant
• pot with soil
• plant (not potted yet)
• water
• time
• notebook and pencil to record your findings

Download Student Worksheet & Exercises

1. Prepare a pot with dirt. Add a measured amount (like 1 cup) of water to dampen the soil. Weigh the pot filled with soil (but no plant).
2. Add a plant to the pot and weigh the whole thing.
3. Subtract the weight you found in step 1 from step 2 to find out how much the plant weighs.
4. You’ll be weighing your pot each day. Weigh the plant before watering (water it the same amount each day) and write it down in your notebook . If you’re giving it water and sunlight, the plant should be getting heavier.
5. Where does this mass come from? You can’t create mass, and yet the plant is getting heavier. How?

You and I get heavier when we eat food. You aren’t giving the plant food, but it is getting food. How? Where does its food come from? The energy from the sun is changed to sugars during photosynthesis, increasing the mass of the plant.

Exercises

1. Where does this mass come from? You can’t create mass, and yet the plant is getting heavier. How?
2. Can energy be created?
3. Can energy be destroyed?

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Photosynthesis is a process where light energy is changed into chemical energy.  As we said in the last section, this process happens in the chloroplast of plant cells.  Photosynthesis is one of the most important things that happen in cells.

In fact, photosynthesis is considered one of the most important processes for all life on Earth.  It makes sense that photosynthesis is really important to plants, since it gives them energy, but why is it so important to animals?  Let’s learn a little more about photosynthesis and see if we can answer that question.

There are many steps to photosynthesis, but if we wanted to sum it up in one equation, it would be carbon dioxide (CO₂) + water (H₂O) makes glucose (C₆H₁₂O₆) and oxygen (O₂).  These words can be written like this:

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6CO₂ + 6H₂O + Light Energy –> C₆H₁₂O₆ + 6O₂

Carbon dioxide, water, and energy combine to form glucose and oxygen.

We learned in the last section that glucose is a kind of sugar.  This sugar is important for energy, so the plant stores all the glucose it creates.  However, the plant releases the oxygen it creates.

Now we can see two reasons why photosynthesis is so important not just to plants, but to animals too.  First, all animals need oxygen to live.  Photosynthesis produces oxygen, so without this process, animals could not survive.  Also, don’t forget that since animals can’t make their own food, they have to eat plants, or eat other animals that have eaten plants.  So without plants, animals would quickly run out of food.

This experiment will demonstrate that carbon dioxide is necessary in photosynthesis.

Materials:

• candle
• lighter with adult help
• large glass jar
• stopwatch
• leafy plant (weeds work also)

Optional: sodium hydroxide and iodine

Download Student Worksheet & Exercises

1.Light your candle. invert the glass over it and time how long it takes the candle to use up all the oxygen and extinguish itself. Write this number down in your journal.

2. Find a young plant or bush, preferably with a lot of growth and leaves. Place your candle next to the plant (don’t burn your plant!) and invert the jar over it again.  Use your stopwatch to time how long the candle stays lit. Write this number down in your journal.

3. Which one do you expect to take longer? What actually happened?

OPTIONAL BUT DANGEROUS…

Place the caustic soda on a disposable plate. Don’t get this on  your hands or eyes – it’s very corrosive. Handle this chemical ONLY with gloves and keep away from small children and pets like dogs and cats.

Place the caustic soda next to the plant and cover with the glass. Leave this setup undisturbed for a few hours. When you’re done, take a leaf from the plant and do an iodine test on it to find out if there is starch present. Simply place a drop of iodine on the leaf. Iodine changes to dark blue when starch is present.

Exercises

1. Describe the process of photosynthesis in words.
2. Write the chemical equation for photosynthesis.
3. What is glucose?
4. Why is glucose important for plants?
5. Why are plants necessary for animals?
6. Does the result of the experiment depend on how large the plant is? Why or why not?

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In eukaryotes there is a nucleus, so a more complex process called mitosis is needed with cell division. Mitosis is divided into four parts, or phases:

Phase 1 – Prophase: In this phase the nuclear membrane begins to break down and the DNA forms structures called chromosomes.

Phase 2 – Metaphase: In this phase the chromosomes line up along the center of the parent cell

Phase 3 – Anaphase: In this phase, the chromosomes break apart, with a complete set of DNA going to each side of the cell

Phase 4 – Telophase: In this phase, a new nuclear membrane forms around each of the sets of DNA

The four stages of mitosis (the cell at the top has not started mitosis) lead to two daughter cells.

A little after telophase, the cytoplasm splits and a new cell membrane forms.  Once again, two daughter cells have formed.  Take a look at this animation for a good overview of mitosis and see if you can identify all the phases.

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Cells continue to divide until a protein tells them to stop.  As they divide, they become different and specialized, eventually making the tissues and organs found in the many different living things we see every day.

Download Student Worksheet & Exercises

Mitosis is part of the cell cycle, a larger process that living organisms use to repair damage, grow, or just maintain condition. In this experiment, we’re going to figure out the time it takes for a cell to go through each of the four mitosis states.

Grab your science journal and here’s what you do:

Materials:

• Compound microscope with slides and coverslip
• Onion (the root tip, not the onion itself) – you can grow your own if you can’t find any at the store (see image at above left). Place the bottom of an onion in a glass of water for a couple of days and you’ll see the roots grow to the size you need (about 2 cm long).
• Science journal

First, set up your microscope.

Next, prepare an onion sample. Take it from the root tip called the meristematic zone (use the picture on the right), just above the root cap at the very end of the tip.

Use the staining technique we show in our Microscope Lab. Cut the sample lengthwise before placing it on the slide.

If you want to stop the cell division process while you watch the slide, you’ll need to prepare a heat fix mount instead (make sure you don’t boil the liquid when you use the candle or you’ll ruin your slide). You can add a drop or two of stain after the heat fix and blot the excess with a paper towel. Add a drop of water and a coverslip and you’re ready to look!

Try different powers of magnification to find the four different stages of mitosis. Count the number of cells found at each stage of mitosis and figure out the percentage. (Total up the number of cells and use this number to divide each count by. Don’t forget to multiply by 100 for percentage!)

Out of all four stages of mitosis, which one takes the most time to complete? The shortest time? What happens to the process if we skip metaphase?

Exercises

1. What is mitosis?
2.  What are the four stages of mitosis?  Briefly describe what happens in each.
3. Out of all four stages of mitosis, which one takes the most time to complete? The shortest time? What happens to the process if we skip metaphase?

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Here’s a fun experiment that shows you how much stuff can pass through a membrane. Scientist call it the  semi-permeability of membranes.

Before we start, take out your science journal and answer this question: What do you think will happen when we stick a piece of celery into a glass of regular water. Anything special?

What if we add a teaspoon of salt to the water? Now do you think anything will happen?
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Let’s find out. First, you’ll need:

• 2 pieces of celery stalk
• salt
• 2 glasses
• a sensitive scale to weigh the celery

Note: If you don’t have a scale, you can rig up a balance by suspending two cups from a either end of of a pencil. Balance the center on a point (like another pencil) and you’ll be able to tell which is heavier at the end of this experiment (see image below).

You’ll need to measure the celery both before and after this experiment since you won’t be able to “read” the weight.

Trim your celery to be the same weight before you start your experiment.

Download Student Worksheet & Exercises

1. First, weigh the celery (both pieces) and record this in your journal.
2. Next, make your hypotonic solution (plain water). Fill a glass with water and stick your celery in for ten minutes.
3. Remove the piece of celery and pat dry. Weight it again and record your results. If you don’t see a weight difference, dip it in again for ten more minutes. Pat dry and weigh again.
4. Now make your hypertonic solution (salt water). Add a small amount of salt to the water (keep adding until no more can be dissolved and a small amount remains on the bottom).
5. Weight the second celery stalk and record it in your journal. Add this new celery stalk to the water. Wait impatiently for ten minutes. Remove and record the weight. Did you notice a difference? (Note – if you left the first one in for 20 minutes, make sure to leave this one in for the same amount of time.)

What effect did the salt solution have on the celery?  Did it change in appearance?  Did it feel different? Record your results in your journal!

Osmosis is the diffusion of water molecules through a membrane, where the water molecules move from high water concentration to areas of low water concentration.

Salt starts osmosis by attracting water and causing the water to move toward and across the membrane. Remember that salt is a solute, and when water is added to a solute, it spreads out (diffuses) the concentration of salt, and that creates a chemical solution.

Imagine the salt concentration inside a cell being the exact same as the salt concentration outside the cell – what would happen? Right – the water level will stay the same and nothing would happen. Now imagine there’s more salt inside of a cell than outside it. What happens now? The water moves through the membrane into the cell causing it to swell with water.

If the cell is placed in a higher concentration of salt (like sticking a carrot in a salt bath), the water will leave the cell, and that’s why the plant cells shrink and wilt. This is also why salt kills plants, becaise it takes water from the cells. This doesn’t just happen in plants, though. Animals can also get dehydrated if they drink ocean water.

Exercises

1. In what direction does water move?
2. What is the process by which water crosses membranes by itself?
3. What are all living things made of?
4. Did the celery in the fresh water weigh more or less? Why?
5. Did the celery in the salt water weigh more or less after a few minutes?

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The carrot itself is a type of root—it is responsible for conducting water from the soil to the plant. The carrot is made of cells. Cells are mostly water, but they are filled with other substances too (organelles, the nucleus, etc).

We’re going to do two experiments on a carrot: first we’re going to figure out how to move water into the cells of a carrot. Second, we’ll look at how to move water within the carrot and trace it. Last, we’ll learn how to get water to move out of the carrot. And all this has to do with cells!

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Osmosis is how water moves through a membrane. A carrot is made up of cells surrounded by cell membranes. The cell membrane’s job is to keep the cell parts protected. Water can pass through the membrane, but most things can’t.

And water always moves through cell membranes towards higher chemical concentrations. For example, a carrot sitting in salt water causes the water to move into the salty water. The water moves because it’s trying to equalize the amount of water on both the inside and outside of the membrane. The act of salt will draw water out of the carrot, and as more cells lose water, the carrot becomes soft and flexible instead of crunchy and stiff.

You can reverse this process by sticking the carrot into fresh water. The water in the cup can diffuse through the membrane and into the carrot’s cells. If you tie a string around the carrot, you’ll be able to see the effect more clearly! Here’s what you do:

Download Student Worksheet & Exercises

Experiment #1: Water moving INTO the carrot via osmosis and UP the carrot.

In this experiment we will see the absorption of water by a carrot. Make note of differences between the carrot before the experiment, and the carrot afterward.

Materials

• 2 carrots
• Sharp knife (be careful!)
• Cutting board
• Glass
• Water
• Food coloring

Procedure :

Step 1: Cut the tip off of a carrot (with adult supervision).

Step 2: Place the carrot in a glass half full of water

Step 3: Place the carrot somewhere where it can get some sunshine.

Step 4: Observe the carrot over several days.

What’s going on?

When surrounded by pure water, the concentration of water outside the carrot cells is greater than the concentration inside. Osmosis makes water move from greater concentrations to lesser concentrations. This is why the carrot grows in size—it fills with water!

Procedure:

Step 1: Re-do the four steps above in a new cup, and this time put several (10-12) drops of food coloring into the water.

Step 2: With the help of an adult, cut the carrot in half length-wise.

What’s going on?

Carrots are roots. They conduct water from the soil to the plant. If we were to repeat this experiment several times—first cutting the carrot at half a day, then one day, then one day and a half, etc—we would see the movement of the water up the root.

Experiment #2: Water moving OUT of the carrot via osmosis

In this experiment we answer the question “what if the concentration of water is greater inside the carrot?”

Materials

• Large carrot
• 3 tablespoons of salt
• Two glasses
• String
• water

Procedure

Step 1: Snap the carrot in half and tie a piece of string around each piece of carrot (make sure they’re tied tightly).

Step 2: Place each half in a glass half full of warm water.

Step 3: In one of the glasses, dissolve the salt.

Step 4: Leave overnight.

Step 5: The next morning pull on the strings. What do you observe?

What’s going on?

The salt-water carrot shrunk while the non-salt-water carrot bloated!

This is because of osmosis. Carrots are made up of cells. Cells are full of water. When the concentration of water outside the cell is greater than the concentration of water inside the cell, the water flows into the cell. This is why the non-salt-water carrot bloated—the concentration was greater outside the cell than inside. The concentration of water was greater inside the salt-water carrot than outside (because there was so much salt!) so the water flowed out of the cell. This made the salt-water carrot shrink.

Questions to Ask:

1. What happens if you try different vegetables besides carrots?
2. How do you think this relates to people? Do we really need to drink 8 glasses of water a day?
3. What happens (on the osmosis scale) if humans don’t drink water?
4. Use your compound microscope to look at a sample and draw the cells (both before and after taking a bath in the solution) in your science journal.
5. What did you expect to happen to the string? What really happened to the string?
6. Which solution made the carrot rubbery? Why?
7. Did you notice a change in the cell size, shape, or other feature when soaked in salt water? (Check your journal!)
8. Why did we bother tying a string? Would a rubber band have worked?
9. What would happen to a surfer who spent all day in the ocean without drinking water?
10. What do you expect to happen to human blood cells if they were placed in a beaker of salt water?

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One way substances can get into a cell is called passive transport. One special kind of passive transport is osmosis, when water crosses into the cell. This experiment allows you to see the process of osmosis in action. Are you ready?

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Download Student Worksheet & Exercises

1. Cut two thin slices of potato. The pieces should be about the same thickness and be slightly flimsy.

2. Place both slices in separate glasses of water.

3. Add salt to one of the glasses.

4. Wait about 15 minutes.

5. Pull out the two pieces of potato and make observations in our science journal.

Did you notice that the potato slice in the fresh water became a little stiffer, while the potato in salt water became rather flimsy?  Remember that cells are made of cells and that the water in the cells flows from areas of low salt concentration to high salt concentration.  That means that if the water outside the cell is saltier than the water inside, water will move from the inside of the cell to the outside. As the water left the cell it was like letting the air out of a balloon. As more and more of the cells lost water, the slice of potato became soft and flexible.  If the water inside was saltier, the opposite happens, and some water goes into the cells, stiffening them up.

Osmosis is the diffusion of water molecules through a membrane, where the water molecules move from high water concentration to areas of low water concentration.

Salt starts osmosis by attracting water and causing the water to move toward and across the membrane. Remember that salt is a solute, and when water is added to a solute, it spreads out (diffuses) the concentration of salt, and that creates a chemical solution.

Imagine the salt concentration inside a cell being the exact same as the salt concentration outside the cell – what would happen? Right – the water level will stay the same and nothing would happen. Now imagine there’s more salt inside of a cell than outside it. What happens now? The water moves through the membrane into the cell causing it to swell with water.

If the cell is placed in a higher concentration of salt (like sticking a carrot in a salt bath), the water will leave the cell, and that’s why the plant cells shrink and wilt. This is also why salt kills plants, because it takes water from the cells. This doesn’t just happen in plants, though. Animals can also get dehydrated if they drink ocean water.

Questions to Ask:

1. How was the concentration of salt different in each cup?
2. Which direction was water flowing in each cup?
3. Why did one potato become stiff, while the other became flimsy?

Let’s do this experiment again, but use beans instead of potatoes.

1. Place enough beans and water in a glass to completely fill it

2. Place the glass on a cookie sheet

3. Leave the glass alone for several hours… even overnight!

4. While you wait, take out your science journal and write about what you expect to happen. When your experiment is ready, record what you found.

Questions to Ask:
1. The beans should begin to fall out of the water. If you look at them, you will see that they have expanded. What happened?

2. Where was the concentration of water greater – inside or outside of the beans? Explain.

Exercises

For Potatoes

1. How was the concentration of salt different in each cup?
2. Which direction was water flowing in each cup?
3. Why did one potato become stiff, while the other became flimsy?

For Beans

4. If you look at the beans, you will see that they have expanded. What happened?
5. Where was the concentration of water greater – inside or outside of the beans? Explain.

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If you think of celery as being a bundle of thin straws, then it’s easy to see how this experiment works. In this activity, you will get water to creep up through the plant tissue (the celery stalk) and find out how to make it go faster and slower.

The part of the celery we eat is the stalk of the plant.  Plant stalks are designed to carry water to the leaves, where they are needed for the plant to survive.  The water travels up the celery as it would travel up any plant.

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Download Student Worksheet & Exercises

1. First, find four celery stalks about the same size with leaves still attached.

2. Mix up a four-cup batch of colored water (try purple).

3. Place your celery stalks in the water, leaf-end up. After an hour or two, take it out and place it on the paper towel. Label your celery stalk with the each time length it was in the water.

4. Repeat this for different increments of time. Try one overnight!

5. Use a ruler and measure how high the water went. Record this in your science journal.

6. Now make a graph that compares the time to distance traveled by placing the time on the horizontal axis and the distance traveled on the vertical.

7. What happens if you start with hot water? Ice cold water? Salt water?

8. What happens if you cut the celery stalk at the base high enough so it straddles two cups of different colors?

Exercises

1. What two types of transport move substances into a cell?
2. How does water get into the celery?
3. What are the tubes in celery called?
4. In what direction does air flow? Hint: Think of the balloon example.
5. What happens to the water after it travels through a plant?
6. Use answers 1-4 to describe the process of water traveling through a celery stalk.

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This experiment allows you to see protozoa, tiny-single celled organisms, in your compound microscope. While I can go in my backyard and find a lot of interesting pond scum and dead insects, I realize that not everybody has a thriving ecosystem on hand, especially if you live in a city.

I am going to show you how to grow a protozoa habitat that you can keep in a window for months (or longer!) using a couple of simple ingredients.

Once you have a protist farm is up and running, you’ll be able to view a sample with your compound microscope. If you don’t know how to prepare a wet mount or a heat fix, you’ll want to review the microscope lessons here.

Protozoa are protists with animal-like behaviors. Protists live in almost any liquid water environment. Some protists are vital to the ecosystem while others are deadly.

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Download Student Worksheet & Exercises

Here’s how you can grow your own to look at under a compound microscope:

1. Leave a glass of water out overnight, to get rid of chlorine. If you are in a hurry, use filtered water (not distilled) instead.

2. Add dead grass to the glass of water. Stir.

3. Add yeast to the glass. Stir again.

4. Allow the glass to sit overnight in a warm place. For best results, let grow and ferment for several weeks.

5. Each day for a week, observe a sample of water and/or grass under the microscope, after the first 24 hours.

6. Sketch the protozoa you see, and note if there are more or less of a certain type as time goes on in your science journal.

Exercises

1. What is a cell?
2.  Why are cells so small?
3.  What is a protozoa?
4.  How does it develop?

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If the cell has a nucleus, the DNA is located in the nucleus.  If not, it is found in the cytoplasm.  DNA is the genetic material that has all the information about a cell.

DNA is a long molecule found in the formed by of two strands of genes. DNA carries two copies—two “alleles”—of each gene. Those alleles can either be similar to each other (homozygous), or dissimilar (heterozygous).

We’re going to learn how to extract DNA from any fruit or vegetable you have lying around the fridge. Are you ready?

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Materials:

• pumpkin OR apple OR squash OR bananas OR carrots OR anything else you might have in the fridge
• dishwashing detergent
• 91% isopropyl alcohol
• coffee filter and a funnel (or use paper towels folded into quarters)
• water
• blender
• clear glass cup

Download Student Worksheet & Exercises

Procedure:

Step 1: First, grab your fruit or vegetable and stick it in your blender with enough water to cover. Add a tablespoon of salt and blend until it looks well-mixed and like applesauce. Don’t over-blend, or you’ll also shred the DNA strands!

Step 2: Pour this into a bowl and mix in the detergent. Don’t add this in your mixer and blend or you’ll get a foamy surprise that’s a big mess. You’ll find that the dishwashing detergent and the salt help the process of breaking down the cell walls and dissolving the cell membranes so you can get at the DNA.

Step 3: Place a coffee filter cone into a funnel (or use a paper towel folded into quarters) and place this over a cup. Filter the mixture into the cup. When you’re done, simply throw away the coffee filter. Note: Keep the contents in the cup!

Step 4: Be careful with this step! You’ll very gently (no splashing!) pour a very small about of alcohol into the cup (like a tablespoon) so that the alcohol forms a layer above the puree.

Step 5: Observe! Grab your compound microscope and take a sample from the top. You’ll want a piece from the ghostly layer between the puree and the alcohol – this is your DNA.

What’s going on?

Veggies and fruits are made of water, cellulose, sugars, proteins, salts, and DNA. To get at the DNA, you first need to get inside the cells and separate it out from the other parts. The blender breaks up the fibers that hold the cells together.

The salt and detergent are added next so they can break down the cell walls. Cell walls of plants are made of cellulose. Inside that cellulose is another cell wall (cell membrane). This membrane has an outer later of sugar and an inner layer of fat.

The detergent is a special molecule that has an attraction to water and fats (which is why it works to get your dishes clean). The end of the molecule that is attracted to fat attaches to the fat part of the cell membrane. When you stir up the mixture, it breaks up the membrane (since the other end likes water). It wedges itself inside and  opens the cell up… which causes the DNA to flow out.

Since DNA dissolves in water, it stays in the vegetable juice. When alcohols is added, the DNA “comes out” of solution as the ghostly white strands seen at the bottom of the alcohol layer.

For Advanced Students:

For advanced students, here’s a set of videos that detail the cell walls, the basic biological molecules, DNA and RNA and how everything works together.

First watch this video below to see how we broke down the cell walls in the DNA extraction experiment:

Here’s a video on how DNA and RNA work:

Here’s a video that describes how the four biological molecules (proteins, lipids, carbohydrates, and nucleic acids) work:

Exercises

1. What are fruits and veggies made of?
2.  What does DNA stand for?
3.  What is DNA?
4.  What is a gene?
5.  Describe the structure of DNA.

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Cells make up every living thing. Take a look at all the living things you can see just in your house. You can start off with you and your family. If you have any pets, be sure to include them. Don’t forget about houseplants as well – they’re alive. Now take a walk outside. You’ll likely see many more plants, as well as animals like birds and insects. Now imagine if all those living things were gone. That’s how it would be if there were no cells, because cells are what all those living things are made of.

Animals, plants and other living things look different, and contain many different kinds of cells, but when you get down to it, all of us are just a bunch of cells – and that makes cells pretty much the most important thing when it comes to life!

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Here’s a video on the difference between animal and plant cells:

Are you wondering what all the different organelles are inside the cell? Here’s a video that goes into all the cool detail (note – this video is more for advanced students):

Now pull out your science journal! As you watch this video below, write down the organelles you see and describe what you think is happening.

What’s going on?

The endoplasmic reticulum, shown in red, transports proteins to the Golgi Apparatus, shown in blue. The Golgi Apparatus packages proteins and sends them where they are needed, either in the cell, or to the cell membrane for transport out of the cell.

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Hans Lippershey was the first to peek through his invention of the refractor telescope in 1608, followed closely by Galileo (although Galileo used his telescope for astronomy and Lippershey’s was used for military purposes).  Their telescopes used both convex and concave lenses.

A few years later, Kepler swung into the field and added his own ideas: he used two convex lenses (just like the ones in a hand-held magnifier), and his design the one we still use today. We’re going to make a simple microscope and telescope using two lenses, the same way Kepler did.  Only our lenses today are much better quality than the ones he had back then!

You can tell a convex from a concave lens by running your fingers gently over the surface – do you feel a “bump” in the middle of your hand magnifying lens?  You can also gently lay the edge of a business card (which is very straight and softer than a ruler) on the lens to see how it doesn’t lay flat against the lens.

Your magnifier has a convex lens – meaning the glass (or plastic) is thicker in the center than around the edges.  The image here shows how a convex lens can turn light to a new direction using refraction. You can read more about refraction here.

A microscope is very similar to the refractor telescope with one simple difference – where you place the focus point.  Instead of bombarding you with words, let’s make a microscope right now so you can see for yourself how it all works together. Are you ready?

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How to Make a Microscope

Materials:

• 2 hand held magnifiers
• dollar bill
• penny

Here’s what you do: Hold one magnifying glass in each hand.  Focus one lens on a printed letter or small object.  Add the second lens above the first, so you can see through both.  Move the lens toward and away from you until you bring the letter into clear focus again.   You just made a microscope!  The lens closest to your eye is the EYEpiece.  The lens closest to the object is the OBJECTive. The image here is of the objective part of a compound microscope.  The different silver tubes have different sizes of lenses, each with a different magnification, so the same scope can go from 40X to 1,000X with the flip of a lens.

How do I determine magnification power for my microscope? Simply multiply the powers of your optics together to get the power of magnification. If you’re using one lens at 10X and the other at 4X, then the combined effect is 40X. You’ll usually find the power rating stamped in tiny writing along the magnifier.

So now you’ve made a microscope.  How about a telescope? Is it really a lot different?

The answer is no.  Simply hold your two lenses as you would for a microscope, but focus on a far-away object like a tree.  You just made a simple telescope… but the image is upside-down!

We don’t fully understand why, but every time we teach this class, kids inevitably start catching things on fire.  We think it’s because they want to see if they really can do it – and sure enough, they find out that they can!  Just do it in a safe spot (like a leaf on concrete) if that’s something you want to do. Click here for a detailed instructional video on how to do this safely.

How do I connect the flaming shrubbery back to the main optics lesson? Ask your child why the leaf catches on fire… and when the shrug, you can lead them around to a discussion about focus points of a lens.  It’s hard for kids to visualize the light lines through a lens, so you can shine a strong light through a fine-tooth comb as shown in the image above.  Use clear gelatin (or Jell-O) shapes as your “lenses” and shine your rays of light through it.  If your room is dark enough, you’ll get the image shown above.

The point where all the lines intersect is where things catch fire, as the energy is most concentrated at this point. Note how the lines flip after the focus point – this is why the telescope images are inverted.  The microscope image is not flipped because you’ve placed the image (and/or your eye) before the focus point.  Play around with it and find out where the focus point is.  Slide your lenses along a yardstick to easily measure distances.

How to Make a Telescope

Materials:

• 2 hand held magnifiers
• window

 
Want to experiment further? Then click for the Optical Bench experiment and also sneak a peek at the Advanced Telescope Building experiment where you will learn about lenses, refractor, and newtonian telescopes.

Ready to buy your own professional-quality instrument that will last you all the way through college? Click here for our recommendations on microscopes, telescopes, and binoculars.
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Make sure you’ve completed the How to Use a Microscope activity before you start here!

This is simplest form of slide preparation!  All  you need to do is place it on the slide, use a coverslip (and you don’t even have to do that if it’s too bumpy), and take a look through the eyepiece.  No water, stains, or glue required.

You know that this is the mount type you need when your specimen doesn’t require water to live. Good examples of things you can try are cloth fibers (the image here is of cotton thread at 40X magnification), wool, human hair, salt, and sugar. It’s especially fun to mix up salt and sugar first, and then look at it under the scope to see if you can tell the difference.

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Here’s what you do:

1. Pull a hair from your head and lay it on a slide. If it’s super-curly, use a bit of tape at either end, stretching it along the length of the slide. Keep the tape near the ends so it doesn’t come into your field of view when you look through the microscope.

2. Lower the stage to the lowest setting and rotate the nose piece to the lowest magnification power.

3. Place the slide on the stage in your clips.

4. Focus the hair by looking through the eyepiece and slowly turning the coarse adjustment knob. When you’re close to focus, switch to the fine adjustment knob until it pops into sharp view.

5. Open your science notebook and draw a circle. Sketch what you see (don’t forget the title and mag power!)

6. When you’re done, lower the stage all the way and insert a new slide… and repeat. Find at least six things to look at. We’re not only learning how to look and draw, but hammering a habit of how to handle the scope properly, so do as many as you can find.

Don’t forget to check the windowsills for interesting bits. Use baby food jars or film canisters to collect your specimens in and keep them safe until you need them.

TIP: If you want to keep your specimen on the slide for a couple of months, use a drop of super glue and lay a coverslip down on top, pressing gently using a toothpick (not your fingers) to get the air bubbles out. Let dry.

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How do the lenses work to make objects larger? We’re going to take a closer look at optics, magnification, lenses, and how to draw what you see with this lesson. Here’s a video to get you started:

Here’s what you do:

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1. Take a look at the eyepiece of your microscope. Do you see a number followed by an X? That tells you the magnification of your microscope. If it’s a 10X, then it will make objects appear ten times larger than usual.

2. Peek at the objective lenses. They’re on the nose of the microscope, and there’s usually 3 or 4 of them. Do you see the little numbers printed on the side of the lenses, also followed by an X? Find the one that says 4. if you look through just that lens by itself, objects will appear 4 times as large. However, it’s in a microscope, so you’re actually looking through two lenses when you use the microscope. What that means is that you need to multiply this number by the eyepiece magnification (in our example, it’s 4 * 10 = 40) to get the total power of magnification when you use the microscope on this power setting. It’s 40X when you use the 10X eyepiece and 4X objective. So objects are going to appear 40 times larger than in real life.

3. Practice these with your microscope – here are the settings on my microscope – help me fill out the table to figure out how to set the lenses for the different magnification powers:

Questions to Ask:

1. What does this table above look like for your microscope?

2. Your microscope may have come with an additional eyepiece. If so, add it to your table and figure out the range of magnification you have.

3. What is your highest power of magnification? Set it now.

4. List three possible combination of eyepiece and objective lenses if the power of magnification is 100X.

Learning to Look

Do how do you use this microscope thing, anyway? Here’s how you prepare, look, and adjust so you can get a great view of the micro world:

Download Student Worksheet & Exercises

1. Carefully cut a single letter (like an “a” or “e”) from a printed piece of paper (newspaper works well).

2. Use your tweezers to place the small letter on a slide and place a coverslip over it (be careful with these – they are thin pieces of glass that break easily!) If your letter slides around, add a drop of water and it should stick to the slide.

3. Lower the stage to the lowest setting using the coarse adjustment knob (look at the stage when you do this, not through the eyepiece).

4. Place your slide in the stage clips.

5. Turn the diaphragm to the largest hole setting (open the iris all the way).

6. Move the nose so that the lowest power objective lens is the one you’re using.

7. Bring the stage up halfway and peek through the eyepiece.

8. If you’re using a mirror, rotate the mirror as you look through the eyepiece until you find the brightest spot. You’ll probably only see a fuzzy patch, but you should be able to tell bright from dim at this point.

9. Use the coarse adjust to move the stage slowly up to bring it into rough focus. If you’ve lowered the stage all the way in step 7, you’ll see it pop into focus easily. (Be careful you don’t ram the stage into the lens!)

10. Use the fine adjust to bring it into sharp focus. What do you see?

Drawing What You See

Learning to sketch what you see is important so that the view is useful to more than just you. Here’s the easy way to do it: get a water glass and trace around the rim on a sheet of paper with your pencil. This gives you a nice, large circle that represents your scope’s field of view (what you see when you look into the microscope). Now you’re ready for the next step:

1. Draw a picture of that the letter looks like under the lowest power setting in your first circle and label it ‘right side up’. Then give the slide a half turn and draw another picture in a new circle. Label this one ‘upside-down’.

2. If you’re using a mechanical stage (which we highly recommend), twist one of the knobs so that the slide physically moves to the right as you look from the side (not through the eyepiece) of the microscope. If you’re using stage clips, just nudge the slide to the right with your finger. Now peek through the eyepiece as you move the slide to the right – which way does your letter move?

3. Now do the same for the other direction – make the slide move toward you. Which way does the letter appear to move when you look through the eyepiece?

4. What effect do the two lenses have on the letter image as you move it around? (Need a hint? Look back at the Microscope Optics Lesson from Unit 9)

Look back at your two drawings above. Let’s make them so they are totally useful, the way scientists label their own sketches. We’re going to add a border, title, power of magnification, and more to get you in the habit of labeling correctly. Here’s how you do it:

Border You need to frame the picture so the person looking at it knows where the image starts and ends. Use a water glass to help make a perfect circle every time. When I sketch at the scope, I’ll fill an entire page with circles before I start so I can quickly move from image to image as I switch slides.

Title What IS it? Paramecia, goat boogers, or just a dirty slide? Let everyone (including you!) know what it is by writing exactly what it is. You can use bold lettering or underline to keep it separate from any notes you take nearby.

Magnification Power This is particularly useful for later, if you need to come back and reference the image. You’ll be quickly and easily able to duplicate your own experiment again and again, because you know how it was done.

Proportions This is where you need to draw only what you see. Don’t make the image larger or smaller – just draw exactly what you see. If it’s got three legs and is squished in the upper right corner, then draw that. Most people draw their image smaller than it really is when viewed through the eyepiece. If it helps, mentally divide the circle into four quarters and look at each quarter-circle and make it as close to what you see as you can.

Exercises

1. Why do we use microscopes?
2. What’s the highest power of magnification on your microscope? Lowest?
3. Where are the two places you should NEVER touch on your microscope?
4. Fill in the blanks with the appropriate word to describe care and cleaning of your microscope:fingers       lowest                                               handsarm                                       toilet paper                                    legs                        dust cover
   1. Pick up the microscope with two ________.  Always grab the _________with one hand and the _______(base) with the other.
   3. Don’t touch the lenses with your _________. The oil will smudge and etch the lenses. Use an optical wipe if you must clean the lenses. Steer clear of ____________ and paper towels – they will scratch your lenses.
   5. When you’re done with your scope for the day, reset it so that it’s on the _________ power of magnification and lower the stage to the lowest position. Cover it with your __________ or place it in its case.
5.  What things must be present on your drawing so others know what they’re looking at?
6.  What’s the proper way to use the coarse adjustment knob so you don’t crack the objective lens?
7.   List three possible combination of eyepiece and objective lenses if the power of magnification is 100X.
8.  Briefly describe how to dry mount a slide.
9.  How could you view a copper penny with your microscope?

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Nose? Objective? Stage? What kind of class is this?  Well, some of the names may sound a bit odd, but this video will show you what they are and how they are used. As you watch the video, touch the corresponding part of your microscope to get a feel for how it works.

NOTE: Be very careful NOT to raise the stage too high or you’ll crack the objective lens!  Always leave a space between the stage and the lens!! Anytime you use the coarse adjustment knob, always look at the stage itself, NOT through the eyepiece (for this very reason). When you use the fine adjustment knob, that’s when you look through the eyepiece.

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More questions to ask:

1. After you’ve learned the different parts of the microscope, swing around and teach it to a nearby grown-up to test your knowledge. See if you can find all these parts: eyepiece, base (legs), objective lens, eyepiece, diaphragm (or iris), stage, fine and coarse adjustment knobs, mirror/lamp, nose.

2. Show your grown-up which parts never to touch with your fingers.

3. What’s the proper way to use the coarse adjustment knob so you don’t crack the objective lens?

Care and Cleaning

1. Pick up the microscope with two hands. Always grab the arm with one hand and the legs (base) with the other.

2. Don’t touch the lenses with your fingers. The oil on your fingers will smudge and etch the lenses. Use an optical wipe if you must clean the lenses. Steer clear of toilet paper and paper towels – they will scratch your lenses.

3. When you’re done with your scope for the day, reset it so that it’s on the lowest power of magnification and lower the stage to the lowest position. Cover it with your dust cover or place it in its case.

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Welcome to our unit on microscopes! We’re going to learn how to use our microscope to make things appear larger so we can study them more easily. Think about all the things that are too small to study just with your naked eyeballs: how many can you name?

Let’s start from the inside out – before you haul out your own microscope, we’re going to have a look at what it can do. I’ve already prepared a set of slides for you below.  Take out a sheet of paper and jot down your guesses – here’s how you do it:

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What is it?

Take a peek and see if you can figure out what each one is. Record your guess on a piece of paper. Don’t spend more than 90 seconds on each one. If you’re working with others, have everyone write down their answers individually, and then work together and discuss each one. Come up with a final group conclusion what’s on each slide before peeking at the answers.

Need answers? Hover your mouse over each slide to reveal the title.

More questions you can ask:

1. List the ways that microscopes are used. Why bother using them anyway? (Can you name four?)

2. What do you already know about microscopes? List two things.

3. What would you really like to learn about microscopes? Name three, at least.

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This is an introduction to the microscope, and we’re going to not only how to use a microscope but also cover the basics of optics, slide preparation, and why we can see things that are invisible to the naked eye. Microscopes are basically two lenses put together to make things appear larger.

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The first thing you need to do is select a compound microscope. (While you can do this lesson without one, it’s really a totally different experience doing it with a scope.) Cheap microscopes are going to frustrate you beyond belief, so here are the ones we recommend that will last your kids through college. You’ll want one with the optional mechanical stage (instead of stage clips), fine and coarse adjustment knobs, and at least three objectives. Click on the shopping list to see what we think are the best deals for the dollar.

If you’ve just purchased a microscope, keep it in its packaging until you watch the videos in this lesson. We’ll show you how to handle it, store it, and where not to touch.  Your first job is to start collecting as many interesting windowsill insects as you can find.

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