The Hydrosphere – water EarthlOur Earth is mostly covered with waterllThe HydrospherelWater on Earth is a unique feature that clearly distinguishes our "Blue Planet" from others in the solar system. lNot a drop of liquid water can be found anywhere else in the solar system. Earth has just the right mass, the right chemical composition, the right atmosphere, and is the right distance from the Sun that permits water to exist mainly as a liquid.lWater is the universal solvent and the basis of all life on our Planet.lllEarth's Water BudgetllAbout 97% of the planet's water is SALTWATER.lOnly about 3% is FRESH WATER.lFRESH WATERü 98.8% of fresh water is frozen in ice capsü 1% of the world's fresh water is accessible for direct human usesü 0.2% of all freshwater is in rivers, lakes, and the atmospherellCOMPONENTS OF WATER BUDGETlSTORAGEØ soil moistureØwater store in a soilüGround WaterüSurface WaterllFLUXESØrate of movement of waterØüInputsüOutputsülSTORAGElGround Water - water in soil or bedrockllSurface Water - includes lakes, rivers, falls, streams, wetlands, and oceansllFLUXES
Inputs
lwater that goes to the storagelprecipitation, runoff, groundwater inflow, and surface water inflowlFLUXES
Outputs
lthe water that goes out of the storagelgroundwater outflow, surface water outflow, evaporation, transpiration, and community needslWhat makes water a very special liquid?lPROPERTIES OF WATERl1. Water is transparent.l5. Water in a pure state has a neutral pH (pH 7). As a result, pure water is neither acidic nor basic.lll10. Capillarity of water
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RlSurface waterlGround waterl Industriall EnvironmentallWATER CYCLElWater Cycle lWater, which covers the majority of the Earth's surface (the hydrosphere), circulates through the lWater Cycle—water is in constant motion
The Sun provides water cycle's energyWater on the surface absorbs heat and evaporates, entering the atmosphereCondensation—water vapor changes back into liquid.Clouds of water become heavy and water falls to Earth as precipitation.The cycle repeats itself continuously.
The Water Cycle
Get a glass of water and put it on the table next to you. Take a good long look at the water. Now -- can you guess how old it is?
The water in your glass may have fallen from the sky as rain just last week, but the water itself has been around pretty much as long as the earth has!
When the first fish swam in the ocean, your glass of water was part of that ocean. When the Brontosaurus walked through lakes feeding on plants, your glass of water was part of those lakes. When kings and princesses, knights and squires took a drink from their wells, your glass of water was part of those wells.
Evaporation: Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air. Do plants sweat?
Well, sort of.... people perspire (sweat) and plants transpire. Transpiration is the process by which plants lose water out of their leaves. Transpiration gives evaporation a bit of a hand in getting the water vapor back up into the air.
Condensation:
Water vapor in the air gets cold and changes back into liquid, forming clouds. This is called condensation.
You can see the same sort of thing at home... pour a glass of cold water on a hot day and watch what happens. Water forms on the outside of the glass. That water didn't somehow leak through the glass! It actually came from the air. Water vapor in the warm air, turns back into liquid when it touches the cold glass.
Precipitation: Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow. Collection:
When water falls back to earth as precipitation, it may fall back in the oceans, lakes or rivers or it may end up on land. When it ends up on land, it will either soak into the earth and become part of the "ground water" that plants and animals use to drink or it may run over the soil and collect in the oceans, lakes or rivers where the cycle starts
Accumulation - the process in which water pools in large bodies (like oceans, seas and lakes).
Condensation - the process in which water vapor (a gas) in the air turns into liquid water. Condensing water forms clouds in the sky. Water drops that form on the outside of a glass of icy water are condensed water. (This term appears twice in the diagram.)
Evaporation - the process in which liquid water becomes water vapor (a gas). Water vaporizes from the surfaces of oceans and lakes, from the surface of the land, and from melts in snow fields.
Precipitation - the process in which water (in the form of rain, snow, sleet, or hail) falls from clouds in the sky.
Subsurface Runoff - rain, snow melt, or other water that flows in underground streams, drains, or sewers.
Surface Runoff - rain, snow melt, or other water that flows in surface streams, rivers, or canals.
Transpiration - the process in which some water within plants evaporates into the atmosphere. Water is first absorbed by the plant's roots, then later exits by evaporating through pores in the plant.
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