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:
- A small diameter long spring (PH0706)
- A partner
- 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.
- Now hold still and wait for the spring to stop moving around. You can use your free hand to dampen the spring.
- 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.
- 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.
- Try to make a standing wave by moving the spring up and down continuously.
- 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.
- How many nodes can you count?
- 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?
- 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.
- Quickly move your hand once in a small circle. This should send a helical wave down the spring.
- Try moving your hand once in a small circle in the opposite direction.
- Now quickly move your hand once in a clockwise circle and then immediately in a single counter-clockwise circle. What does that look like?
- You can also move your hand side-to-side to send a sideways wave down the spring.
- 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?