The volcano experiment is a classic way to get kids involved with science. Start by molding clay around an upside-down funnel. Remove the funnel, then press a small container (like the kind a 35mm film comes in) into the top of the volcano hole . Through the top of the volcano, add in two spoonfuls of baking soda, about a spoonful of dish soap and 5 drops of food coloring. Now time for the explosion! Add about a tablespoon of the vinegar into the volcano and watch it erupt. The chemicals will react, making a colorful, foam-like substance that oozes out of the volcano.
This experiment does not have the "wow factor'"of the volcano experiment, but shows kids what happens during a chemical reaction. Start by pouring a clear, carbonated drink, such as lemonade, into a clear glass. Next, drop the raisins in and watch what happens. The raisins should start bobbing and jumping around in the glass. This is because the bubbles of carbon dioxide gas in the drink are far less dense than the drink or the raisins. The gas bubbles attach to the wrinkles on the raisins and chemically react with the surface, making the fruit jump about.
If you are looking for a quick and easy chemical reaction experiment, this is it. Start by gathering a few old copper pennies and filling a small glass with lemon juice. Drop the pennies into the lemon juice one at a time. Leave them for 10 minutes. Remove the coins from the juice and place on a kitchen towel. Watch what happens to the coins. They should appear shiny and new because the acid in the lemon juice chemically reacts and removes the oxidation coating.
Conduct this experiment outside, as it can get very messy. Place a 2-liter bottle of cola on a flat surface, then remove the cap. Quickly drop four mentos candies into the bottle and stand back. Watch what happens next. The mentos will quickly react with cola; the pressure will build up and escape, spewing the cola into the sky. You can also do this experiment with a smaller bottle of cola and two mentos instead of four. It will make less of a mess!