Water on Earth

More than 70% of the Earth’s surface is covered with water. Scientists estimate that the Earth contains about 1.36 billion cubic kilometers of water. Water makes up the majority of all life forms. Most animals and plants contain more than 60% water.

The Hydrologic Cycle Water on this planet can be stored in any one of the following places: atmosphere, oceans, lakes, rivers, glaciers, snowfields, and groundwater. Water moves from one place to another through processes like evaporation, condensation, precipitation, deposition, runoff, infiltration, sublimation, transpiration, melting, and groundwater flow. –Hydrologic Cycle

Hydrologic Cycle Very simple and broken into 5 Parts Condensation Precipitation Infiltration Runoff Evaporation

Condensation Water vapor condenses in the atmosphere to form clouds.

Precipitation As clouds form, winds move them across the globe, spreading out the water vapor. Eventually the clouds can't hold the moisture, they release it in the form of precipitation, which can be snow, rain, hail, etc.

Infiltration When precipitation seeps into the ground.

Runoff If precipitation occurs faster than it can seep into the ground, it becomes runoff. Runoff remains on the surface and flows into streams, rivers, and eventually large bodies such as lakes or oceans.

Evaporation The power of the SUN is driving this cycle by causing evaporation. Evaporation is the change of liquid water to a vapor. Sunlight aids this process as it raises the temperature of liquid water in oceans and lakes. As the liquid heats, molecule are released and change into a gas. Warm air rises up into the atmosphere and becomes the vapor involved in condensation. And the Cycle starts all over again

Water is always cycling The cycle takes about 16 days, on average, to be renewed. The cycle is slower in large lakes, glaciers, ocean bodies, and groundwater.

Earth’s Water Supply Oceans - Contains about 97% of the Earth’s water supply. Ice – 2.05% of the Earth’s water. Surface Waters – About .02% Groundwaters – .5% of the Earth’s water.