Dancing Raisins

There was a classic commercial several years ago with cartoon raisins in sunglasses singing, "I Heard it Through the Grapevine," but this is a little different.  This activity is still entertaining, even if it might be difficult to outfit your raisins with little sunglasses.

What you need:  A tall, clear glass or cup; 1 can of club soda, sprite, or seltzer water (can't be flat); raisins.  Really, that's all.

What to do:  Pour the soda in the glass and drop a few raisins in.  Watch the raisins go up and down for up to 5 minutes!

How does this work?  Initially, the raisins sink, but then as bubbles from the carbon dioxide in the soda form on their surface, it causes them to rise again.  Soda contains dissolves carbon dioxide (CO2), which slowly bubbles out of solution over time.  These bubbles attach to the raisins and eventually provide enough lift to carry them to the top of the glass.  When the raisins reach the top, the bubbles burst and the carbon dioxide is released into the air above the liquid. The raisin then sinks and the process repeats itself.  Simple, but cool.

This is one of those actitivies that is better observed in video, than in pictures.  To see a short video of the dancing raisins, click here.  Thanks to Patricia Wong from U.T. Arlington for contributing this activity to DISCUS.  It is safe and simple...great for elementary school children or even pre-K.  When the students look close enough they can even see the bubbles forming on the raisins that causes them to rise to the top.  Ask them what they think is happening (Try it with chocolate chips, too).  Patricia cites Mary Elizabeth off of pbskids.org for this activity, a URL for which can be found here. As always, we would love to hear your comments about this activity.  Did it work?  How can you make it even better?