Fun Science Dancing Raisins

Teach your healthy snack how to dance! Sun-Maid snack packs will never be the same again!


You will need a clean glass, a clear carbonated drink, raisins.

Method:

# 1 – Fill a glass up with carbonated drink, drop in 10-15 raisins. Watch as they start to wibble wobble dance.

Try this experiment with different drinks, see what causes the most dancing! You can also throw in some small pasta, lentils, noodles, corn! Try different variations to see what gets the best results!

The raisins will bob up and down for several minutes.  Because the surface of  raisins are rough, tiny bubbles of carbon dioxide gas are attracted to it.  These bubbles increase the volume of the raisin, but contribute very little to its mass as they don’t weigh anything.  As a result, the overall density of the raisin is lowered, causing it to be carried upward by the more dense fluid surrounding it.

This is known as the Archimedes’ Principle  which states that “the buoyant force exerted on a fluid is equal to the weight of fluid displaced.”  As the raisins now have a greater volume, they displace more water, causing the fluid to exert a greater buoyant force. The buoyant force of the surrounding fluid is what pushes the raisins to the top.

Once the raisins reach the top, and meet the air, the bubbles pop.  This makes the raisins more dense, causing them to sink.  As more bubbles adhere to the raisins as they sink, the density of the raisins decreases and they rise to the surface again. This experiment very clearly shows that an increase in volume (as long as the mass increase is negligible) will lead to a decrease in density.  The bubbles that attach themselves to the raisins are like little life jackets that make the raisins more buoyant by increasing their volume.

Which is exactly how life jackets, rubber rings and and arm bands work!