Who knew raisins could be so entertaining?  With a little water, soda water, and a few old grapes, your kitchen will become a laboratory for understanding how buoyancy works.

What you’ll need

  • Two large, clear glasses
  • Clear soda water with a lot of bubbles
  • Water
  • At least eight raisins

How to do it

Talk to your child about the way some objects sink in water and others float. Fill one glass with water and the other with soda water. Ask your child what she thinks will happen when she puts the raisins in the different liquids. Will the raisins sink or float? Why? Have her put about four raisins in each glass of water and observe.

The raisins should sink in water. In soda water, the raisin should sink and then float, and then sink and float again. Discuss what happened to the raisins with your child. The raisins float in soda water because the bubbles attach to the raisins, making them rise to the surface. At the surface the bubbles detach and the raisin sinks. Then the cycle repeats.

At this age your child does not need to understand all aspects of buoyancy, but if you would like more information on this subject, check out Exploratorium: Bouyancy.