Original Plastic Slinky

Price: $8.95

Everyone wants a slinky. This is the Original Plastic Slinky sold since 1945. Watch your colourful slinky walk its way down stairs or just juggle it back and forth in your hands. This clever spring is also great for simulating the properties of different waves, including sound waves.

Age: 5 +
What You Get
Original Plastic Slinky, 10cm in diameter. Colours vary.

How does it work?
Sound waves are created by vibrations and transmitted through matter in all directions. But it's hard learning about sound waves when you can't see them. This is where your new plastic slinky comes in. Not only are slinkies fun, but they can be used to demonstrate longitudinal sound waves.

In the classroom (or anywhere for that matter), make a longitudinal wave by stretching a slinky between two students. One should hold their end as motionless as possible - perhaps against their chest or stomach for support. The student holding the other end should pull several coils towards themselves. Then watch as a longitudinal sound wave travels back and forth along the length of the slinky. As alternative to pulling coils, try having one student tap their end of the stretched, still slinky with their finger or pencil. The same wave effect is created.

Slinkies can also be used to demonstrate other waves, like traverse and standing. A traverse wave is an example of a water wave. To demonstrate, stretch a slinky between two students, and have one move their end of the slinky left and right very quickly. The other end should be held still. To create a standing wave, move one end of a stretched, still slinky back and forth at constantly changing rates. A number of waves will travel through the slinky and reflect back on themselves.
  • Waves: longitudinal, traverse and standing.
  • Sound waves.
  • Inertia, gravity, potential and kinetic energy as it moves down stairs.
  • Centrifugal force. Swing the slinky around your head gradually increasing speed. The position of the coils shows the resultant force formed by two simultaneous forces: gravity and the outward, horizontal centrifugal force.

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