Inertia Coin Drop

Why will a coin on a sheet of paper above a glass drop into the glass when the paper is flicked out of the way?

Time: about 1 minute


  • a coin
  • glass
  • small sheet of paper


  • Place the coin on the sheet of paper on top of a cup
  • Flick the paper out of the way


  • What happens to the coin?
  • Can you explain the results?


The coin has Inertia, defined by Galileo as the tendency of a body to resist change in motion. When you flick the paper, the coin tends to want to stay put and then falls when the paper is no longer there to support the coin.







Can you try a slower flick of the paper? What happens if you move the paper away too slowly? Try using a very light weight (low inertia) object such as a small piece of paper. Does the smoothness of the paper matter? What if you used sand paper instead of craft paper?

Please follow and like us:

Coco Science

Coco is interested in STEAM with a particular interest in the A. She has a hamster named Marshmallow and likes to read, craft, cook and dance.