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Dancing raisins

A tall glass of sparkling water where raisins covered in bubbles move up and down.

Materials

a tall clear glass, freshly opened sparkling water (clear soda also works), 5 to 10 raisins, a glass of plain water to compare

Steps

  1. Fill the tall glass three-quarters full with sparkling water.
  2. Drop in a few raisins. Do they sink or float?
  3. Drop a few raisins into the glass of plain water too.
  4. Watch closely for a few minutes. What happens to the raisins in the sparkling water?

What happens?

At first the raisins sink, because they are heavier than the water they push aside. Then tiny bubbles of carbon dioxide stick to the wrinkles on the raisins. The bubbles work like little life jackets and lift the raisin up. At the top the bubbles pop, and the raisin sinks again. Plain water has no bubbles, so those raisins stay at the bottom. Source: Science-U.

Safety for grown-ups

Raisins can be a choking risk for little kids. A grown-up should handle the raisins with children under 4, and don't eat raisins while you play. Wipe up any spills. An adult should supervise.

Source: science-u.org (opens in a new tab)