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Tuesday, August 9, 2011

A Little Science, at Snacktime......

Dancing Raisins Experiment


tap water
clear glass, jar, or plastic cup
several raisins
2 tablespoons baking soda
2 tablespoons vinegar

Fill the cup 3/4 of the way with water. Drop the raisins into the cup. Stir the baking soda into the water until it is dissolved.  (This is a great time for your young scientist to practice measuring because the quantities don't have to be as exact as for baking) Now add the vinegar and watch what happens!

You've just created a chemical reaction--which gives the raisins energy to dance!  In the plain water, the raisins sink to the bottom, because they are heavier than the liquid.  When the baking soda is added and dissolved, the raisins still stay at the bottom.  But, when you add the vinegar, the solution creates carbon dioxide gas.  When the gas bubbles bump into the raisins, they attach to the outside of the raisins and help them float to the surface.  The combination of a carbon dioxide gas bubble and a raisin is lighter weight than the water, so they rise to the top.  When the bubble pops, the raisin floats back down to the bottom again.
And there you have it--dancing raisins!

Basic Science Vocabulary

liquid: One of the three states of matter: a substance that flows, rather than a solid or a gas.
chemical reaction: When two or more chemicals (substances--in this experiment the baking soda and vinegar) are combined and the combination creates a new substance.
carbon dioxide:  gas composed of carbon and oxygen.
energy: ability to do work (like dancing!)

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