Kids, would you like to make your own "dancing California raisins" by using chemistry? All you need are two clear plastic cups, one filled with water and the other filled with a cold, clear soda like 7-Up. And raisins of course.

Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

First put a few raisins in the water. What happens? They sink. Why? The raisins are heavier and more dense than water. Now put a few raisins in the soda. This time they should also sink, but then gas bubbles of carbon dioxide will stick to the raisin and eventually lift it with them to the top. Then what? The bubbles pop and the raisins sink again, whereupon its "dance" can continue! Now, what does this tell you about how a life jacket works?  

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Kathleen Carrado Gregar, PhD, Argonne National Labs 
[email protected]
February 1992