D ISTRIBUTION OF W ATER ON E ARTH

THIRST VIDEO

T HE H YDROSPHERE Hydrosphere: the part of Earth that contains water 97% of Earth’s water is salt water Only 3% is fresh water: ( 30% groundwater, 68% frozen, 2% on surface)

S ALTWATER Oceans cover 71% of Earth’s surface ( about ¾ ) Land takes up 29% of Earth’s surface ( about ¼ ) 2 categories of water in the Hydrosphere…based on Salinity = % salt content Saltwater: 97% of Earth’s water Oceans 35 g salt/kg of water How many oceans are currently recognized today??!!

F RESHWATER Freshwater: < 1 g salt/kg of water ONLY 3% of Earth’s water is fresh 2/3 of that is frozen in glaciers, ice caps, & icebergs (pieces of glaciers floating in ocean) 1/3 of that is liquid & accessible in lakes, ponds, rivers, streams, or underground

F RESHWATER R ESOURCES Most freshwater is frozen at the polar ice caps!! Glaciers are masses of ice and snow that move slowly over the Earth’s surface.

W HERE ’ S THE WATER ?

The Great Lakes are the largest freshwater System on earth. They contain 84% of North America’s surface freshwater and 21% of the world’s surface fresh water supply. Only the polar ice caps contain more fresh water.

F RESHWATER R ESOURCES 1/3 of Earth’s freshwater is groundwater!! Groundwater forms when water moves through soils and sediment and collects in spaces underground. An aquifer is a rock layer that stores water in the spaces between the rock and allows water to flow through it.

A QUIFERS Underground permeable rock or sediment that contains water Particles in ground act like filter to water!!

G ROUNDWATER Water that seeps into the soil & is pulled down by gravity Can move or sit under the surface if there are spaces between the rock/soil particles (permeable) Water will seep down until it hits an impermeable surface, then fill up from there ( like your bathtub with the drain closed !) The region filled with ground water = Saturation Zone The top surface of this area = Water Table

A/C W ATER T ABLE & S ATURATION Z ONE

G ROUNDWATER TO THE S URFACE V IA … 1.) Man-made Well – pipe dug into ground to extract water from aquifer 2.) Artesian Well – water flows naturally to surface because it’s under pressure 3.) Spring – water flows to surface because surface of land dips below water table 4.) Hot Spring/Geyser – water heated up by rocks, pushes up to surface due to pressure

M AN -M ADE W ELL

A RTESIAN W ELL & S PRING

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W ATER C YCLE – Q UICK R EVIEW 1. Sun heats the water on the surface of Earth  2. Freshwater evaporates into atmosphere as water vapor (salt in ocean stays behind )  3. Water vapor cools & condenses on dust particles to form clouds  4. Water falls back to Earth as precipitation in the form of rain, sleet, snow, or hail  5. Precipitation that hits surface either gets absorbed into ground, stays trapped as standing water, or moves downhill as “run-off” back into lakes, ponds, rivers, streams, oceans **The amount of water on Earth stays the same !!**