Clear drinking glass, food coloring, cake decoration sprinkles, vanilla ice cream, drinking straw, soda water, spoon, chocolate chips and chocolate chip cookies

What You Do

1. Fill one-third of the cup with chocolate chips. Pour clear soda over the chocolate chips.

2. Cover the chips and soda with a layer of ice cream. Note where the soda moves

3. Break the cookie into large lumps and layer them over the ice cream. Add a layer of decorating sprinkles. Note how the ice cream

keeps the top layer from mixing with the bottom layer.

4. Mix some soda with food coloring. Pour the colored soda over the layers and watch where it goes.

5. Put your straw into the bottom of the cup, into the chocolate chip layer. Slowly suck on the straw and watch as the level of clear soda goes down. Where does the colored soda go?

University of Waterloo Professors Alan Plumtree (mechanical engineering) and Alfred Rudin (chemistry) design appropriate technology. Not all parts of the world have the latest engineering materials on hand. Appropriate technology means building with easily accessible materials such as rope or a leather belt instead of a unique machine part. These two scientists developed a hand-operated water pump in the late 1970s that is still being used in developing countries today!