Test Tube Science:Dancing Raisin

Materials:
   -One test tubes
   -One raisin
   -10 mL soda pop

Background:
For a gas to come out of a liquid it needs a nucleation site.  The raisin provides nucleation sites for the carbon dioxide in the soda pop.  The carbon dioxide sticks to the raisin surface until it is brought to the surface of the soda.  The bubbles pop and the raisin drops to the bottom and the process repeats.

Directions:
Pour 10 mL soda into the test tube.  Now place the raisin into the soda.  Watch what happens.  What else can you get to dance (try a pea or peanut, bead or button)?  Does the time between rising and falling change over time?