Did you do the experiment with the water on your hand disappearing? It may be a good idea to do it before doing this one. It is C131.02. At the end, it says that we could get the evaporated water to return. Now, we are going to cause water to evaporate, and then get it back again.

We'll put a small dish of water inside a large glass jar, seal the jar, and watch what happens. [Do you understand the meaning of the word, "seal?" It is more than just putting a lid on the jar. It means to make the lid fit so well that nothing--not even air--can get in or out. We'll make a seal by putting petroleum jelly on top of the rim of the jar before putting on the lid.]

Take a look at the little dish from time to time, and see if the water evaporates.

You can see with your own eyeballs that that water did not disappear. It left the dish (by evaporation), and returned to the sides of the jar (by condensation). So there is the evidence! Everything has to be somewhere!

Let's get a clean, dry jar, and do the same experiment, only using cooking oil in the little dish instead of water. We can do it also with alcohol, or with ice cubes. We might want to feel the droplets that have condensed to see if the oil and the water feel the same.