I came across a statement online that said that an average cloud has a weight of 1 million pounds. My main question is, does a cloud actually have weight on Earth or was the term "weight" a colloquial expression meaning "mass"?
From my understanding, weight is a force defined as W = mass × gravity, or essentially F = ma. Because the cloud is not falling, its acceleration is 0 -- that is, the acceleration of -9.8m/s2 exerted by Earth's gravity must be counteracted by another equal and opposite force in order for the cloud to be stationary in mid-air, hence the "a" portion of F=ma is 0, so F, and therefore weight, must be 0. Is this thinking correct?
However, when the state changes from gas to liquid -- that is, when it starts raining - the water molecules in the liquid state obviously have weight. So my secondary question is, does a molecule's state change affect its weight? For gases which are "lighter than air", is their weight negative? (I suspect yes because of the force equation).