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The Dancing Grapes Experiment

Not enough time on your hands to think of scientific experiments your child can do? Think that most require lots of shopping? Actually, you’ll find most of what you need to conduct meaningful experiments right in your kitchen. The challenge, however, is knowing what to do.

Science is all about discovering how things work and trying to solve problems. Simple, hands-on experiments that begin with “What do you think will happen?” or end with “Can you make it happen differently?” get children’s minds in the right place. Even letting children “play” with the materials before starting gets them thinking about how these interact together. Encouraging children to help whenever they can by reading steps, measuring out materials, and cleaning up maximizes their learning experience and investment.

The Dancing Grape Overview:

The following easy-to-set-up experiment involves mixing baking soda in water with some vinegar to create carbon dioxide gas. Grapes added to this mixture will sit at the bottom at first, and then, as the bubbles collect on the sides of the grapes, they will begin to float. When they reach the top, the bubbles will pop and the grapes will sink again. The cycle will repeat with the grapes going up and down until all of the bubbles are done.

Understanding buoyancy will help your children get the most from the experiment, so here’s a quick explanation: Buoyancy is the measure of how something floats or sinks in a liquid. Rolled up tin foil sinks in water, but if you make it into the shape of a boat, it floats. You change the density of the tin foil as you make it boat shaped. In this experiment, the grapes initially are too dense for the water, but the bubbles help to increase their buoyancy.


  • A tall clear water glass
  • water
  • baking soda
  • vinegar
  • grapes
  • teaspoon
  • paper towels


  1. Fill clear water glass ¾ full of water.
  2. Mix 1 teaspoon of baking soda into the water until it is nearly clear (dilute the baking soda as needed).
  3. Put 2-3 grapes into the glass.
  4. Observe how the grapes sink to the bottom and explain how the grapes are denser than the water.
  5. Ask what will happen when you put vinegar into the baking soda water (this will test whether they have any prior knowledge of mixing the two).
  6. Have the child pour approximately ¼ cup of vinegar into the glass (put paper towels under the cup in case it bubbles over).
  7. Watch the bubbles gather on the sides of the grapes, causing them to slowly rise and then fall.
  8. (If you don’t have baking soda and vinegar, 7-Up or Sprite work well).

This is a simple, yet informative, experiment for your kids. They’ll love the grapes bobbing up and down.

The experimenting doesn’t have to be over yet, however. In fact, this is when the science lesson actually begins. Your kids might ask if this will work with other types of fruit (blueberries? strawberries? raisins?) They might choose a different cup size, different amounts of baking soda and vinegar, or more or less water.  Whatever they attempt and, by encouraging their experimenting, you may be helping them to generate a lifelong fascination with the world of science.