Extreme Science: Penny Shine

What you will need:

  • Metal Slinky ™
  • Juice pouch (ie. Capri Sun)
  • Tape
  • Various size cups (paper and/or plastic)
  • Adult supervision


  1. Hold your Slinky with your arm stretched out in front of you so that you are holding the top ring of the Slinky.  Release the bottom portion of the Slinky (holding on to the top ring still) and allow the bottom portion of the slinky to hit the floor when it drops.  You may hear a slight vibrating or reverberating sound coming up the slinky as the base hits the floor.
  2. Now, place a juice pouch inside the top of the slinky.  Stretch your arm out and drop it again as you did in the previous step.  The reverberating sound should be a little more distinct or noticeable this time.
  3. This time, use some tape to tape the top ring of your slinky to the bottom of a cup.  Now, holding onto the base of the cup (with the cup upright and the slinky taped to the bottom of the cup) drop the slinky again and allow the base of the slinky to hit the floor as in the previous steps.  The sound should be amplified quite a bit this time!

What is going on?

When the bottom of the slinky hits the floor, it causes it to vibrate and sends waves back up the slinky towards your hand.  Since the key to sound is vibration, you will be able to hear this if you listen closely.  By placing the juice pouch in the top of the slinky, the vibrations are now passed on to the pouch as well allowing you to hear it a little better.  By taping the cup to the top of the slinky, you are allowing the entire cup to vibrate and, due to the shape of the cup, the sound is amplified much better than in the juice pouch.

Try this:

Try different size cups or cups made from different materials.  Try using a metal pie pan,  Try various object you can find around the house to see what amplifies these vibrations the best.

Radical Rick

Extreme Science