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# Explore Wave Motion with Springs!

This activity uses the classic spring toy and a long loose spring to explore wave motion. The initial activities take 15-20 minutes – followed by a lot of free play with the spring! Intended for ages 5 and up.

What you’ll need:

Getting started:

1. With a partner stretch the spring out far enough so that it isn’t dragging on the ground. You should be able to go 20 ft or more.
2. Now hold still and wait for the spring to stop moving around. You can use your free hand to dampen the spring.
3. Move your hand just once in a quick up-and-down motion. You should see a little wave shape move down the spring, hit the other side and come back.
4. Count how many times the wave is able to go down and come back before it dies out.

This type of wave is called a transverse wave because the shape of the wave is not in the direction that the wave travels. The shape is an up-and-down shape, but the wave moves along the length of the spring.

Wave motion is really just a complicated self-perpetuating chain reaction. As your hand moves upward it pulls up the coils close to you. Those coils pull up the coils a bit further out, and so on, making the wave move down the spring.

Next:

1. Try to make a standing wave by moving the spring up and down continuously.
2. After a bit you won’t see waves going down the spring; it will look like parts of the spring are stationary and parts are waving up and down like crazy. The stationary parts are called nodes.
3. How many nodes can you count?
4. Try to change the speed with which you move your hand up and down. Can you decrease the number of nodes? Can you increase the number of nodes?
5. How is the speed of your hand motion related to the number of nodes?

Send other types of waves, like a helical wave for example.

1. Quickly move your hand once in a small circle. This should send a helical wave down the spring.
2. Try moving your hand once in a small circle in the opposite direction.
3. Now quickly move your hand once in a clockwise circle and then immediately in a single counter-clockwise circle. What does that look like?
4. You can also move your hand side-to-side to send a sideways wave down the spring.
5. Can you create helical standing waves? What do they look like? Can you create side-to-side standing waves?

Okay – we’re done!  Phew! Now you can explore other ways to use the spring. What can you imagine?