- HYDROSPHERE:
The Hydrosphere is made of the liquid or watery material of our planet. It surrpounds most of the surface of the Lithosphere.
The Hydrosphere covers about 75% of the surface of the Earth. The continents make up about 25% of the Lithosphere surface.
The Hydrosphere includes the oceans, seas, lakes, rivers, streams, and other bodies of water.
Water in the form of rain, snow, clouds, and atmospheric moisture is also part of the hydrosphere.
Along the margins of continents, a Continental shelf, very gentle in slope, extends outward to a depth of a few hundred feet.
Beyond the continental shelf lies (in most places) a steep Continental slope, followed by a relatively flat Abyssal plane.
The abyssal plane forms most of the deep ocean, but there are occasional islands, sea mounts, and deep-sea trenches.
The oceans are bisected by several mid-ocean ridges, of which the mid-Atlantic ridge has been studied the most.
- WATER CYCLE:
Water evaporates all the time from the ocean surface and from the surface of other bodies of water, even from puddles.
Animals and plants also give off water in the form of urine, moisture released during respiration, and moisture released from leaves (transpiration).
Most atmospheric moisture drifts upward and mixes with the Troposphere layer of the atmosphere. Much of this water forms clouds.
Clouds are really patches of air containing water in the form of tiny liquid droplets and/or ice crystals.
Warm air can hold a lot more moisture than cold air. The moisture content of an air mass is called its humidity.
When humid air cools, it may no longer be able to hold all its moisture. The excess condenses into water droplets that coalesce into bigger droplets.
Precipitation is formed by water droplets when they get too big to remain suspended in the atmosphere.
Water that precipitates usually falls to the surface as rain. If it is cold enough, it may fall as snow instead.
Rainwater runs downhill immediately into ponds and streams that drain into rivers and eventually back into the oceans.
Snow remains frozen for a while as a snowpack or icepack, especially at higher altitudes and high latitudes. Much of it melts in spring and summer.
Most of the runoff from rain and from melting ice and snow eventually returns to the oceans.
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