Schematic illustration of a wind mill.

Spicy Music

How Does Energy Create Sound?

 

Materials

  • plastic cup
  • plastic wrap
  • rubber band
  • black pepper
  • cell phone

Try This

  1. Pull the plastic wrap tight over the top of the plastic cup and secure it with the rubber band.
  2. Turn on some loud music on the cell phone.
  3. Place the cup on the phone's speaker.
  4. Sprinkle some black pepper on the plastic wrap. Turn up the music until you see the pepper dancing.

What's Going On?

Although we can't see sound, it is created by waves passing through air molecules. In this case, the cell phone speaker moved with the music, creating waves in the air. The waves hit the plastic wrap and made it vibrate, which caused the pepper to dance around. The same thing happens when we hear: our ear drum vibrates with the sound energy that reaches it.

Schematic illustration of a paper cup wrapped with plastic wrap is placed on the cell phone.