Activity Overview
Grab a couple of easily accessible items from your pantry and let some raisins give you and your family an entertaining science lesson about density and buoyancy. Kids of all ages will be intrigued by the little show that the raisins will put on before their eyes as they watch this experiment unfold.
Materials Needed
- A clear tall glass, vase or jar
- vinegar
- water
- 8-10 raisins
- baking soda
How To Do It
- Fill your glass container halfway with water.
- Add 2 heaping tbs. of baking soda and 1/4 cup vinegar to the water.
- The solution will start to fizz.
- At this time, drop the raisins into the glass container.
- Initially the raisins will likely fall to the bottom, but watch closely as they begin to rise to the top and fall again giving the appearance that they are bouncing.
- The raisins should put on quite a show for up to an hour.
Scientific Explanation
The raisins are much denser than the solution that they are in, therefore they fall to the bottom of the liquid. The vinegar and baking soda cause a reaction that releases carbon dioxide which adheres to the rough surface of the raisin which increases the buoyancy of the raisin and makes it rise to the top. When the raisins reach the top of the liquid, the carbon dioxide gas is released into the air and the raisin again sinks down to the bottom of the glass until more CO2 bubbles attach themselves again and make their way to the top.
