Condensation is the process by which water changes from gas to a liquid. Some examples are the moisture on the bathroom mirror after you take a hot shower, dew on the morning grass, and your visible breath on a cold day.
It is easy to do a simple demonstration of condensation. All it takes is a couple of plastic cups, some water, and some ice.
- 2 identical plastic cups
- watch or clock with a second hand or stopwatch
- Fill one cup with water.
- Fill the second cup with ice and then add water until it is to the level of the water in the first cup.
- Use the towel to dry the outsides of both cups so you know you are starting with two dry cups.
- Note the time.
- After fifteen minutes, examine the exteriors of both cups.
The outside of the cup with just water should be pretty dry. But the cup with the ice should be moist. This is because air has water vapor in it. Water vapor is water in the form of gas. The cup with the ice in it became cool and cooled off the air around it, causing the water vapor in the air to turn to liquid water which attached as drops to the cup, making the outside of the cup with the ice in it damp.
- Try it with just one or two ice cubes instead of lots of ice. Is there a difference in the amount of moisture on the outside of the cup?
- Try using different types of cups – glass, metal, Styrofoam. What differences do you notice and how can you explain them?