When you put raisins in glass of water, what happens?
They sink of course.
So is it possible to make those raisins rise to the top?
Yes indeed. In this simple baking soda experiment.
For this, you will need,
A pint glass
Bicarbonate of Soda (Baking Soda)
Fill the glass half full with warm water
Add a drop of food colouring to tint the water. (This has no scientific bearing on the experiment other than I like things to look pretty!)
Add two heaped teaspoons of Bicarbonate of Soda.
Add a few raisins
Put the glass in a tray (just in case is overflows!)
Top of with white vingear
Watch the effect
You should see the raisins begin to rise and fall
The science bit
The vinegar and bicarbonate of soda reacted to form carbon dioxide as one of the products. The carbon dioxide bubble collect over the many surfaces of the raisin. Because carbon dioxide is lighter than water it rises to the top and takes the raisin with it. As the bubbles pop at the surface the raisin descends, only to be covered in bubbles gain at the bottom until the reaction finishes.
Can you think of anything else this would work with?