Where does dew come from sky or ground?
As you are already told, dew comes from the moisture in the air when it reaches dew point. But why does it comes on the ground, trees, etc? Well, in order to go from gas to liquid, water needs to give away energy in form of heat and the tiny water molecules have virtually no mass to do that. But whenever they come in contact with something that has a mass, zap! It condenses as a tiny water drop! Note that this is also valid for liquid going to solid. If it is freezing outside and there is fog, it can’t just go into ice crystals until it touches something with a mass. That’s how you get frost rim on the trees, you car, just anything. The most dangerous part is when that happens on the leading edge and propeller of a light aircraft. As a pilot myself, I know that freezing fog is something I must never encounter! Don’t ask me how I know! When ice melts or water evaporates, it is the opposite: it needs to take energy in form of heat and thats’ why we sweat: the evaporation of the sweat is
