As we can learn in the "Liquids" section, water has lots of tricks. We're learning in the "Gases" section that air has lots of tricks, as well.

Dip a finger or hand in warm water, and wave it until it dries. How does it feel? Where is the water? Did it fall off your hand and splash on the floor? No? Well, where is it, then?

It is important to remember that nothing on earth is really "gone." It is somewhere else, perhaps in another form. Everything has to be somewhere. Remember that.

When liquids, such as the water on your hand, seem to disappear, they have changed into an invisible gas. When liquids disappear, they have evaporated; the molecules have been absorbed by the surrounding air.

We can do the same thing by putting a small amount of water into a saucer, and setting it in a sunny window. After awhile, the water will be gone. But not really; it will have changed by evaporation, and become invisible.

We could get it back if we put a jar of ice cubes on the countertop!