Matter is another word for the material that makes up all the stuff in the whole world. The three forms, or states, of matter are solids, liquids, and gases. One very useful thing about matter is the way it can change between it's forms. In this activity you'll watch matter change from one state to another!

Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

You'll need ice, 3 clear plastic cups, water, a measuring cup, masking tape, ballpoint pen, paper towels, and a really humid day. Use the masking tape and pen to label the cups A, B, and C. Place 1/2 cup cold water in each cup. Wipe the outside of the cups with the paper towels to insure they are dry. Leave cup A alone as your control experiment. Add one ice cube to cup B. Fill cup C with ice until it is nearly full. Let them sit 5 minutes. Look at the outside of the cups. Describe what you see, then use your finger to test for any liquid on the outside of the cups. What is this liquid and where did it come from?

What's happening here? You are watching a gas change to a liquid as a result of condensation. The liquid came from water vapor (water in its gaseous state) in the air, which has condensed to form liquid on the surface of the cold cup. Does one cup seem to have more liquid on the outside than another? Why do you think it does?

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Kathleen Carrado Gregar, PhD, Argonne National Labs 
[email protected]
August-September 1997

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Reference: WonderScience, 1997, 11(5).