Science Projects for Kids: Producing Sounds

Ever wonder how your voice carries across a room? Make a sound wave model to mimic the movement of air molecules when carrying sound. You may be surprised to find that it takes a lot more than just a strong set of lungs to be heard.

What You'll Need:

Step 1: Cut six pieces of thread, each 10 inches long, and attach an end of each thread to a ball bearing using tape.

Step 2: Tie the other end of each thread to the horizontal piece of a clothes hanger, leaving about one inch between each thread that you tie. Hang the hook of the clothes hanger from a shower-curtain rod.

Step 3: Pull back one of the end bearings. Let the bearing go so that it strikes the next one. Watch what happens. It hits the second, which swings and hits the third, and so on.

Sound travels through the air in the same way. A vibration causes one molecule of air to move and bump into another molecule, which then moves at the same rate and bumps into a third molecule, and so on.

Go to the next page to learn how sound travels through a simple telephone.

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In the past, when kids wanted to share a secret or play communication games, they'd use a simple telephone. It may not have been as cool as a cellphone or a walkie-talkie, but it was effective. Try this science project on producing sound to learn how a simple telephone works.

What You'll Need:

Step 1: Use a pen to punch a small hole in the middle of the bottom of each of two hard-plastic containers, such as cottage cheese containers. Thread one end of a 12-foot piece of string through the hole in each container so that the end is inside the container. Tie knots in each end so the string will not pull out through the hole.

Step 2: Hold one cup, and give the other to a friend. Walk far enough apart so the string between the cups is pulled tight. The string should not be touching anything except the plastic containers.

Step 3: Ask your friend to hold the cup over one ear while you whisper into the other cup.

Your voice will make the string vibrate. The vibration will travel along the string to the other cup, and your friend will clearly hear what you whispered. Now listen while your friend whispers.

Build other phones that use different lengths of string and different kinds of containers, and compare how well they work.

Continue on to the next page to learn how volume and mass can produce bottle music.

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Bottle music is a science project for kids on producing sound that explores how volume and liquid affect sound waves. After experimenting with different types of bottles and levels of water, show your friends how this project works and start a bottle music band!

What You'll Need:

Step 1: Stand eight empty bottles side by side on a table in front of you. Fill the bottle on the left about 1/4 of the way full with water.

Step 2: Add water to the next bottle so that the water level is a bit higher than in the first bottle. Continue adding water to the bottles so that each one has a little bit more water in it than the bottle to its left.

Step 3: Blow across the bottle on the left, and you'll hear a low note. Blow across the bottle on the right, and you'll hear a high note. By adjusting the amount of water in each bottle, you can produce a whole musical scale.

When you blow across the bottle, you cause the air inside to vibrate, which produces a sound. The amount of air in the bottle affects the sound it makes. The bottles with more air produce low sounds, and the bottles with less air produce high sounds.

Learn how to stop sound in its tracks on the next page.

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You don't need to be a super hero to stop sound. This sound barriers science project for kids shows how easy it is to halt sound waves in their tracks.

What You'll Need:

Step 1: Go into your backyard and stand about as far from your partner as your house is wide. (That should be about 30 feet or so.) Try to talk to one another.

As long as there is nothing between you and your partner, you should be able to hear one another fairly well, though you may have to raise your voice a little.

Step 2: Now stand on one side of a house while your partner stands on the other side. Try to shout something to your partner and see if you can be heard clearly. Have your partner shout something at you.

You may have heard something, but perhaps you could not make out what your partner was saying. Was the sound weak and distorted?

Try the same experiment with a wall between you and your partner. Try it with a fence, a window, a blanket, and other types of barriers. Does the thickness of the barrier matter?

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Contributing Writers: Sound Barriers by Maria Birmingham, Karen E. Bledsoe, and Kelly Milner Halls