Turn Raisins into Diving Subs
In this science experiment, kids will explore chemical reactions and buoyancy as they turn raisins into diving subs.
The simple explanation: We made bubbles through a chemical reaction. The raisins have a bumpy surface, which quickly collects the gas bubbles. The bubbles act like tiny balloons, lifting the candy to the top. But the bubbles pop at the top, and the heart sinks again. Then the whole cycle repeats!
More science:
- When an object can float, we say it is “buoyant.” At first, the raisins you added to your vinegar and baking soda solution sank right to the bottom. But when air bubbles formed on the sides, they began to float! When the bubbles popped, the objects sank again. This same principle is used to make submarines sink and float in the ocean.
- The baking soda dissolves into the vinegar.
- Baking soda is a base; vinegar is an acid. When combined, they create a chemical reaction that produces a gas. The gas is carbon dioxide -- the same gas that humans breathe out.
Materials
- Tall clear container - 1 of this item per student
- Vinegar - enough to fill the container 2/3
- Baking soda - 2-5 teaspoon per student
- Raisins - several per student
Instructions
Fill the tall clear container about 2/3 full with vinegar.
Drop in the raisins; they will sink to the bottom.
Add about 1 teaspoon of baking soda per cup of vinegar used and stir. (Adding more baking soda will create a big volcanic eruption! For this experiment, we are trying only to create moderate bubbling.) Bubbles should immediately form from the chemical reaction between the baking soda and vinegar, and begin to accumulate on the sides of the small objects. Eventually there will be enough bubbles to pull the raisins to the surface, much like a hot air balloon can pull a basket through the sky. But when the bubbles reach the top of the vinegar they will pop, and the raisins will sink again. This cycle will repeat itself over and over until the bubbling from the reaction stops.
You can prolong the experiment by adding more baking soda when the bubbles slow down.
Extension:
When you are finished observing the raisins, make a volcano by dropping in a heaping Tablespoon of baking soda!
This activity is also fun to do with candy hearts around Valentine's Day.
