Wikijunior:Big Book of Fun Science Experiments/Raisin Dance
What you need to do
Get a clear drinking glass (or beaker). Fill it with a bubbly and clear drink like Sprite.
Get raisins and add them slowly and keep putting them in the beaker.
The raisins rise up to the top, then fall down, and then rise to the top again. It's like they're dancing.
The Science Bit
The bubbly drink that you used is packed full of a gas called Carbon Dioxide (CO2). There's so much CO2 that it bubbles out of the drink. That's what makes it fizzy.
When you drop the raisins in, some of the bubbles stick to the raisins. Since the bubbles are trying to rise up out of the drink, they pull the raisins along for the ride. Once a raisin gets to the top, the bubbles come out of the drink and pop. Since the raisin doesn't have bubbles holding it up anymore, it falls back down where the process starts all over again.
Don't forget to clean up! You can still eat the raisins and drink the soda.