Summary Add raisins, or other materials, 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) Lessons activity is in Floating, sinking and buoyancy Density, buoyancy and pressure States of Matter and State Changes 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 soda water is water with carbon dioxide gas dissolved in it. 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 sink. 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
