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Unit 1 Lesson 2 The Water Cycle What Goes Up … What is the water cycle? • The movement of water between the atmosphere, land, ocean, and living things makes up the water cycle. • Rain, snow, and hail fall on the oceans and land. On land, ice and water flow downhill. • Water vapor moves upward and is carried great distances by the wind. The wind also creates ocean currents. How does water change state? • Water on Earth is found as a liquid, solid, and gas. • Water absorbs energy from its surroundings as it melts from solid to liquid. • Water also absorbs energy as it evaporates from liquid to gas, or when it sublimates from solid to gas. • Water releases energy to its surroundings when it condenses from gas to liquid. • Water also releases energy when it freezes from liquid to solid or deposits from gas to solid. • No water is lost during these changes of state. How does water reach the atmosphere? • Water reaches the atmosphere as water vapor through evaporation, transpiration, and sublimation. • Evaporation occurs when liquid water changes to water vapor. • Most of the water vapor evaporates from Earth’s oceans. • Transpiration is the release of water vapor into the atmosphere by plants. • Sublimation is when solid water changes directly to water vapor without first becoming a liquid. • Sublimation can occur when dry air blows over ice or snow, where it is very cold and the pressure is low. • Identify each process as evaporation, sublimation, or transpiration. What happens to water in the atmosphere? • Condensation is the change of state from gas to liquid. It can occur in the air as clouds, fog, or mist, or on the ground as dew. • Precipitation is any form of water that falls to Earth from clouds. • Rain, snow, and hail are common forms of precipitation. How does water move on land and in the oceans? • Streams, rivers, and the water that flows over land are types of runoff. Runoff flows downhill. • Some of the water on land seeps into the ground. This process is called infiltration. Once undergound, the water is called groundwater. Groundwater also flows downhill. • Glaciers, which may be called “rivers of ice,” flow downhill and sometimes flow to the ocean, where pieces may break off. • Winds move ocean water on the surface in great currents over long distances. • Cold or salty water will sink in the ocean, forming deep ocean currents that move large amounts of water. Water Works What does the water cycle transport? • The water cycle moves energy and matter. • Energy is transported by changes in state and by the movement of water from place to place. • Matter is transported all around the world by ocean currents, rivers, and glaciers. • Identify the processes in the water cycle.