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