Mini Blogpost 2: Dancing Raisins!

Today, I made raisins dance in a cup full of soda.

Materials I used:

• a tall, clear glass or plastic cup
• a few raisins
• a can of clear, colorless soda like 7-up or Sprite
  

Procedure:

1. Pour the can of soda into the clear cup. Watch how the carbon dioxide gas (bubbles) are released from the liquid.
2. Then, drop 6 or 7 raisins into the cup.
3. Watch what happens to the raisins.

Observation: The raisins all sink to the bottom at first but then one by one, they quickly ascend to the top and then just as quickly, they sink to the bottom again.

Science: At first, the raisins sink to the bottom of the cup because raisins are more dense than the liquid. Since it is a carbonated drink, releases bubbles or carbon dioxide. When the raisins stick to some of the bubbles, the raisin starts to float up to the top because of the increase in buoyancy. However, when the raisin reaches the top, the bubbles pop and are released into the air. Since the buoyancy is decreased, the raisin sinks to the bottom again. The raisins float and sink until most of the carbon dioxide gas is gone into the air. As time passes, the raisin gets too heavy to float to the surface.