# Explore Wave Motion with a Classic Toy!

This activity uses the classic spring toy and a long loose spring to explore wave motion. The initial activities take only about 10 minutes – followed by a lot of free play with this awesome toy! Intended for ages 5 and up.

What you’ll need:

Time to explore:

1. Stretch the spring between two people but not very far or you might bend it! There should be a little dip between the two of you, and you should be able to stretch it at least 6 feet or so without damaging it.
2. Have one person squeeze together a bunch of coils with their thumb and fingers and then let them go. You should see a chain reaction as the coils push on other coils a bit further out, and so on, down to the other side, reflect and come back – maybe even a few times.
3. Try it again and count how many times it goes back and forth.
4. What is it that is traveling back and forth between the two of you?

This type of wave is called a longitudinal wave. It’s called that because the wave shape is in the same direction as the motion of the wave. The wave shape is made of slightly reduced spacing between the coils. The shape goes along the spring, not up-and-down like the transverse wave.

Another name for this type of wave is a pressure wave. The pressure of the coils pushes on the next section of the spring causing it to compress, and so on down the spring. Sound waves are pressure waves. And if you’ve ever used a tin-can phone – it is pressure waves in the string that transmit the sound from your tin can to your friend’s tin can.

You can also launch waves by holding the spring in one hand and then bumping that hand quickly with your other hand. This helps solidify the fact that the spring compression comes from pressure – the pressure of one hand hitting the other.

Okay – we’re done!  Phew! Now you can send the short spring down some stairs!