The Water Cycle

The Water Cycle Earth’s Water Cycle • A cycle is a process with no beginning or end. It repeats over and over. • Matter moves and changes through cycles, driven by energy (the ability to make things move or change). • The sun’s energy is the driving force behind most cycles on Earth, including the water cycle. • The Water Cycle is the movement of water between the Earth’s surface and the atmosphere (mixture of gases and dust surrounding Earth. The Water Cycle The water cycle includes evaporation, transpiration, condensation, and precipitation. Click the picture below for a preview. Evaporation • Evaporation is the change from a liquid to a gas. • During evaporation, the sun’s energy heats liquid water, changing it to water vapor (water in the form of gas). This vapor rises into the air. Transpiration • Transpiration is the release of water vapor into the air by plants. • Plants release water through openings in their leaves which is heated by the sun and turned into water vapor. Condensation • Condensation is the change of water from a gas to a liquid. To condense is to change from a gas to a liquid. • Water vapor is condensed into tiny droplets of liquid water. The droplets form clouds. Condensation = GAS to LIQUID Precipitation • Precipitation is water that falls from the atmosphere. • Precipitation occurs when the water droplets in the clouds become too heavy and fall in the form of rain, sleet, snow, or hail. Runoff • Runoff is water that flows over the surface of the land. • After precipitation, water soaks into the soil and collects as groundwater. Groundwater is pulled back up by plants and people and gravity pulls water downhill as runoff. This water evaporates and the cycle continues. The Sun and the Ocean • The Sun and the Ocean are extremely important to the water cycle. • The Sun’s energy drives the entire water cycle. Since nearly 97% of the Earth’s water is found in the oceans and seas, the ocean supplies much of the water in the water cycle.