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Term Term description
water cycle

The Earth's water cycle, or hydrologic cycle,  is made up of four processes: evaporation, condensation, precipitation, and collection. When the sun heats up water on the Earth's surface, the water turns into vapor through evaporation. The water vaporizes and cools, then turns into liquid clouds through condensation. Precipitation of snow or rain occurs when water has heavily condensed to the point that the air cannot hold it anymore. When water falls back to the ground through precipitation, it is transported to bodies of water or through soil into the ground water.

water footprint

The total volume of freshwater used to produce the goods and services consumed by an individual, community, or business. Water use is measured as volumes consumed (evaporated or incorporated into a product) and/or polluted per unit time.

water resource management

Planning, developing, distributing and managing the optimum use of water resources within a given region. It is a sub-set of water cycle management.

water stress

When the demand for water exceeds the available amount during a certain period or when poor quality restricts its use human activity. Water stress occurs during droughts.

water table

The highest underground level at which the rocks and soil in a particular area are completely inundated by ground water.

water vapor

Water vapor is a very important component of the hydrologic cycle and is also considered to be a greenhouse gas. Heat radiated from the Earth gets absorbed by water vapor molecules within the lowest levels of the atmosphere, which traps the Earth's heat from escaping to the outer atmosphere.


An area of land where peripheral boundaries are deliminated by ridges or high points, and within which all streams and rivers flow down hill and ultimately drain into a single body of water like a river, lake, or ocean.


A unit for measuring power; one watt is the equivalent of using one joule of energy per second.


The distance between one peak or crest of a wave and the next peak or crest.


Weather is the condition of the atmosphere over a short period of time; weather can change from minute-to-minute, hour-to-hour, day-to-day, and season-to-season.

West Antarctic Ice Sheet

The segment of the south pole continental ice sheet that covers West (or Lesser) Antarctica. It is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea.


Aquatic ecosystems such as swamps, bogs, and marshes where water either covers the soil or is present at or near the surface, particularly in the root zone, at least a good portion of the year, including the growing season. Wetlands play key roles including acting as filters, removing pollutants, including metals, from waters. They serve as reservoirs, and they aid flood and erosion control by absorbing excess water. Wetlands are home to a great variety of plant and animal species, some endangered, that have evolved to live in the wetland's unique conditions.

wind farms

A group of wind turbines in the same location used to produce electricity.

wind turbines

The popular name for a device that converts kinetic energy from the wind into electrical power, without the use of an actual turbine.


Sloped side of a mountain that is colder and gets more rain.


In science, using a force to move an object a certain distance.

World Meteorological Organization

A specialized agency of the United Nations, the World Meteorological Organization (WMO) was established in 1950. It is the UN's authoritative voice on the state and behaviour of the Earth's atmosphere, its interaction with the oceans, the climate it produces and the resulting distribution of water resources.


The overall meaning that people give to their lives and to their relationships with other human beings and the natural world.

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