By Emma Morgan-Mueller Water Science Evaporation! By Emma Morgan-Mueller Water Science Our class has been studying water in all forms, ice, or frozen water, water in it's liquid form, and steam, or water vapor. Our class did some experiments with water, like what would happen if you put a damp paper towel in a cup with a lid on it (so the paper towel isn't exposed to air), and a damp paper towel in a cup without a lid on it. Our class put the cups in a scale, then left them alone. The next day the cup with the lid on weighed more than the cup with the lid off. This happened because the water that was in the the paper towel evaporated and the water became a gas and the gas expanded out of the cup. The cup with the lid on still had the water in it, but what had happened to that cup was that the water that was in the paper towel became vapor, but since the vapor couldn't expand it became condensation, which is is the change in the phase of matter from the gaseous phase into liquid droplets or solid grains of the same element/ chemical species. No, not condensation. Condensation is water vapor in the air that loses enough heat to condense into a liquid. This is what happens to the mirror in a bathroom when you take a shower. Warm vapor loses heat to the cooler glass and it condenses to form a liquid on the glass. Your sweat is more like leakage. When I sweat, is that condensation?