Easy and fun for the young ones!
Fill your drinking glass with your clear carbonated beverage. Drop a few raisins in, and observe. Your raisins will start dancing (going up and down) once the carbonated bubbles attach themselves to the raisins.
-7-Up (Sprite and other clear, carbonated beverages will work as well)
-Tall, clear drinking glass
-Several fresh raisins
Less than 1 hour