This is a recording of a recent live teleclass I did with thousands of kids from all over the world. I’ve included it here so you can participate and learn, too!

Sound is a form of energy, and is caused by something vibrating. So what is moving to make sound energy?

Molecules. Molecules are vibrating back and forth at fairly high rates of speed, creating waves. Energy moves from place to place by waves. Sound energy moves by longitudinal waves (the waves that are like a slinky). The molecules vibrate back and forth, crashing into the molecules next to them, causing them to vibrate, and so on and so forth. All sounds come from vibrations.

Materials:

• 1 tongue-depressor size popsicle stick
• Three 3″ x 1/4″ rubber bands
• 2 index cards
• 3 feet of string (or yarn)
• scissors
• tape or hot glue

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Click here to go to next lesson on Pressure Waves.

A sound wave is different from a light wave in that a sound is a mechanical wave, which requires particle interaction in order to exist. Light waves can travel in the vacuum of space, and we’ll talk more about this in our next section when we get to light.

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Using the properties of light and sound waves, we’ll be able to actually see sound waves when we aim a flashlight at a drum head and pick up the waves on a nearby wall.

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If you haven’t already done this next experiment about frequency, do it now:

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Before we get too technical with sound and learning about what it is, let’s have some fun looking at sound waves. Make sure you’re not doing this experiment with good speakers, because you may damage them!

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