Dancing Raisins Experiment

Since so many of you insist on hitting my blog with a search for Dancing Raisins, I thought I would at least post experiments you can use.

Experiment 1: Carbon dioxide gas dissolved in pop gives them their fizz. You can use the carbon dioxide fizz using pop or soda pop or soda (depending on what part of the country you are from. Since I’m from Illinois, I’m going to call it pop) to make raisins dance!

You will need:
1 can of colorless pop, like 7-Up or Sprite.
A tall, clear glass or plastic cup.
Several fresh raisins.

Pour the can of pop into the tall glass. Notice the bubbles coming up from the bottom of the glass. The bubbles are carbon dioxide gas released from the liquid.

Drop 6 or 7 raisins into the glass. Watch the raisins for a few seconds. Describe what is happening to the raisins. Do they sink or float? Keep watching. What happens within the next several minutes?

Info: Raisins are denser than the liquid in the pop, so initially they sink to the bottom of the glass. The pop releases carbon dioxide bubbles. When these bubbles stick to the rough surface of a raisin, the raisin is lifted because of the increase in buoyancy. When the raisin reaches the surface, the bubbles pop, and the carbon dioxide gas escapes into the air, thus causing the raisin to lose buoyancy and sink. Rising and sinking of the raisins continues until most of the carbon dioxide has escaped, and the pop goes flat. With time the raisin will get soggy and will become too heavy to rise to the surface.

Carbonated beverages are prepared by putting the beverage into a can under high pressure of carbon dioxide gas. This high pressure causes the carbon dioxide gas to dissolve in the liquid. When you open a can of soda, the noise you hear is produced by the carbon dioxide gas as it rushes out of the can. When the can is opened, the decreased pressure allows some of the carbon dioxide gas dissolved in the liquid to escape. This is what makes the bubbles in pop.

Experiment 2: Generate the carbon dioxide gas using the reaction of baking soda and vinegar.

You will need:
Baking Soda.
Vinegar.
A tall, clear glass or plastic cup.
Several fresh raisins.

Fill your glass about 1/2 full with water. Add one teaspoon of baking soda and stir until it is dissolved in the water. Add 6 or 7 raisins to the glass. SLOWLY pour in vinegar until the glass is about 3/4 full. The vinegar and baking soda react to form carbon dioxide bubbles, and the raisins will dance!