The Water Cycle The water cycle is the continuous movement of Earth’s water from the ocean to the atmosphere to the land and back to the ocean. Driven by energy from the sun. Contains the same water (same amount too!) since the formation of the Earth Water Cycle Rap How did you flow as a water molecule through the Water Cycle? http://earthguide.ucsd.edu/earthguide/diagrams/watercycle/ Where can water exist on the Earth? Clouds Ocean Snow Rain Stream/River Ocean Lake Ground water Water Vapor Glacier/ Ice Living Things (People, animals, plans, etc) Ground Water Groundwater is the part of precipitation that seeps down through the soil until it reaches rock material that is saturated with water. Water in the ground is stored in the spaces between rock particles (no, there are no underground rivers or lakes). Groundwater slowly moves underground, generally at a downward angle (because of gravity), and may eventually seep into streams, lakes, and oceans. Ways that Water Travels through the Water Cycle Evaporation Transpiration Infiltration Condensation Precipitation Run-Off Evaporation The sun heats liquid water, causing it to rise into the atmosphere as water vapor. Water evaporates directly from oceans, lakes, rivers, falling rain, plants, animals, and other sources where the sun may excite water molecules. Transpiration Transpiration is the process by which plants lose water out of their leaves. Similar to an animal perspiring (sweating) Infiltration Infiltration is the process in which water on the surface ground enters the soil. The rate decreases as the soil becomes saturated. If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. Condensation Condensation takes place when water vapor cools and changes into water droplets that form clouds in the atmosphere. You can see the same sort of thing at home... Pour a glass of cold water on a hot day and watch what happens. Water forms on the outside of the glass. That water didn't somehow leak through the glass! It actually came from the air. Water vapor in the warm air, turns back into liquid when it touches the cold glass Precipitation Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth. Precipitation forms in the follow ways: Rain Snow Sleet Hail Run-off Precipitation that flows over land into streams and rivers. This water later enters the ocean, river or lake. Distribution of Earths Water Amount of Water on Earth Pollution of Water Dirty water is the world's biggest health risk, and continues to threaten both quality of life and public health in the United States. When water from rain and melting snow runs off roofs and roads into our rivers, it picks up toxic chemicals, dirt, trash and disease-carrying organisms along the way. Many of our water resources also lack basic protections, making them vulnerable to pollution from factory farms, industrial plants, and activities like fracking. This can lead to drinking water contamination, habitat degradation and beach closures.