Jumping Raisins Experiment

Try this activity using things you already have at home!  For this experiment you will need the following:

• Colorless soda (like 7-Up or Sprite)
• A tall, clear glass or plastic cup
• Several raisins (fresh raisins work best)

Directions

1. Pour the soda into the tall glass.
2. Notice the bubbles coming up from the bottom of the glass. (The bubbles are carbon dioxide gas released from the liquid.)
3. Drop about 6 raisins into the glass.
4. Watch the raisins for a few seconds.

What happens to the raisins?  Do they sink or float?
What happens over the next few minutes?

Why it Works

Raisins are denser than the liquid in the soda, so at first they sink to the bottom of the glass. The soda releases carbon dioxide bubbles, and when these bubbles stick to the rough surface of a raisin, the raisin rises because bubbles rise. When the raisin reaches the surface, the bubbles pop, and the carbon dioxide gas gets released into the air. Once the bubbles pop, the raisin sinks. This rising and sinking of the raisins continues until most of the carbon dioxide has escaped, and the soda goes flat.  Also, after a while the raisin gets soggy and becomes too heavy to rise to the surface.

Experiment

1. What happens when you put pieces of uncooked pasta in the soda?
2. Can you find other objects that jump in the soda?