Activity

Dancing raisins

Summary
Add raisins to soda and watch them cycle through sinking and floating.
Science content
Chemistry: States of Matter, Properties of Materials (K-7)
Chemistry: Atoms, Molecules (3-7)
Materials
  • bottle of uncoloured soda drink at room temperature
  • dried raisins/cranberries/currants
  • other materials to try e.g. lentils, other foods with nooks and crannies in them
Procedure

Open the soda.
Add a few raisins (or pour soda into a cylinder or tall jar, then add the raisins).
Watch them rise and fall.

The carbon dioxide in the soda comes out of solution and attaches to the raisins.
This decreases their overall density, so they float to the surface.
At the surface, the bubbles pop, the raisin becomes more dense than the liquid again, and sinks.
The cycle repeats.

Notes

Does not work with cold soda. I assume the gas does not come out of solution as easily, so that fewer bubbles attach to the raisins.
Lentils move faster to start, but get soggy more quickly.

Grades taught
Gr 4
Gr 5
Gr 6
Gr 7
Teaching site
ingridscience afterschool
Seymour Elementary