Science Academy
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title
Dancing Raisins
time
5–10 minutes
image
age
4+
difficulty
Easy
hypothesis
"What do you think will happen to the raisins when you drop them into a glass of sparkling water?"
material
A clear glass
material
Sparkling water (or soda water)
material
A few raisins
step
Fill the glass with sparkling water or soda water
step
Drop a few raisins in the glass
step
Watch closely as the raisins sink and then start moving up and down!
observation
How long did it take before the raisins started moving? Did they move up and down more than once? What happened to the bubbles clinging to a raisin once it reached the top?
explanation
Sparkling water is full of tiny carbon dioxide bubbles. Raisins are wrinkly, giving bubbles lots of spots to cling to — enough bubbles make a raisin lighter than the surrounding water, so it floats up. At the surface the bubbles pop and escape, the raisin gets heavy again, and it sinks — repeating until the water goes flat.