Transcript Water Cycle
Water Cycle The Movement of Water What is it? • Our water cycle is a closed system, meaning, water is not lost nor created. • Water that falls today, fell before, and will fall again! • There are many steps in the water cycle. Some main parts to the water cycle are: evaporation, condensation, precipitation, transpiration, surface runoff, infiltration, and ground water. Evaporation • Liquid water turns into water vapor (caused by heat)--the Sun’s radiant energy heats water and causes it to become water vapor • Most of the water vapor comes from the oceans—water vapor does not contain salt • Trees lose water also, this is called transpiration Condensation • Condensation is caused when water vapor (evaporated water) cools and becomes water droplets • These water droplets combine with dust and other small particles to create clouds Precipitation • Water falls to the earth as rain, snow, sleet, or hail • This occurs when the water becomes to heavy to remain in the air What happens after precipitation? • Some of the water gets used by living things (plants and animals) • Some water seeps into the ground (infiltration) and becomes ground water • Some water flows on the ground (surface runoff) into lakes, rivers, streams, etc. Transpiration • Transpiration occurs when water leaves plants—kind of like a plant sweating • This is a form of evaporation Water vapor leaving the tree and entering the air Surface Runoff • Surface runoff occurs when precipitation falls on to hard (impervious) surfaces • Water cannot penetrate these surfaces so it can flow directly to a water source (i.e. lake) • This can cause pollution to the waterways Infiltration • Infiltration occurs when precipitation gets absorbed by the land • This water can become part of the ground water (underground bodies of water) • This process cleans the water Groundwater • Groundwater is water that has infiltrated (penetrated) the ground • It creates bodies of water underground • This is a source of drinking water for many people