The Water Cycle Background Information Water is one of the most important resources on earth.
Water seems magical because it changes form and is found in three states of existence.
In its liquid state as we most commonly know it, it is called water. In its solid state, water is known as ice. In its gaseous state, water is called steam or vapor. You can feel water vapor in the air on a hot and humid day. You can see water vapor condense against a cold glass of milk.