Humidity is when the air is moist, or has lots of water in it water can also evaporate, or turn into a gas. If a lot of water turns into gas it is humid. Rain is water that falls from clouds. A cloud is made of water. When a cloud gets heavy it will drop water.
Snow is frozen rain.
All water is made of billions and billions of water molecules. Molecule are microscopic. Water can also be in the form of a bubble. A bubble forms when air goes into water and creates a perfect sphere. This is 139,400,000 sq.