The Water Cycle Learning Goal • After reading this presentation, summarizing and labeling a diagram, you should be able to define and explain the following terms: – Evaporation, transpiration, condensation, precipitation, infiltration, evapotranspiration, and ground water. Directions • Read each slide. • Complete each term on your Water Cycle notes sheet. The Water Cycle Water never leaves the Earth. It is constantly being cycled through the atmosphere, ocean, and land. This process, known as the water cycle, is driven by energy from the sun. The water cycle is crucial to the existence of life on our planet. Trace water through the arrows as it cycles from earth to atmosphere and back. The Water Cycle - Evaporation During part of the water cycle, the sun heats up liquid water and changes it to a gas by the process of evaporation. Water that evaporates from Earth’s oceans, lakes, rivers, and moist soil rises up into the atmosphere. Transpiration The process of evaporation from plants is called transpiration. (In other words, it’s like plants sweating.) Evapotranspiration • Water goes from the land to the atmosphere by evaporation from the soil and other surfaces, and by transpiration from plants. Condensation As water (in the form of gas) rises higher in the atmosphere, it starts to cool and become a liquid again. This process is called condensation. When a large amount of water vapor condenses, it results in the formation of clouds. Precipitation When the water in the clouds gets too heavy, the water falls back to the earth. This is called precipitation. Runoff When rain falls on the land, some of the water is absorbed into the ground forming pockets of water called groundwater. Most groundwater eventually returns to the ocean. Other precipitation runs directly into streams or rivers. Water that collects in rivers, streams, and oceans is called runoff. Infiltration • Infiltration is the process where precipitation or water soaks into soil and moves into rocks through cracks and pore spaces. Most rainwater and snow end up infiltrated into the ground. Now label your diagram on the other side of your notes sheet. • When you are finished, go back to the class webpage and check your answers to the diagram. • Then click here. Click each button on the left side to read and review the water cycle.