The Water Cycle and Water Usage Objectives Methods Glossary References Menu . The Water Cycle and Water Usage Introduction Water is essential for life to exist on this planet Earth. Consisting of two hydrogen atoms and one oxygen atom, water is one of the few compounds which can exist as a liquid, gas or a solid within the narrow temperature range of life. Gravity also plays an important role in returning water from the atmosphere to terrestrial aquatic reservoirs. The amount of water vapor the atmosphere can hold is dependent on air temperature.
Warm air can hold larger quantities of water vapor than cold air.
When the atmosphere is holding as much water vapor as it possibly can it is considered to be saturated . Menu Objectives Understand the characteristics of water. Understand how the water cycle functions. Calculate your household water consumption. Generate ideas on how to reduce hater use in your household.