D ISTRIBUTION OF W ATER ON E ARTH. THIRST VIDEO

DISTRIBUTION OF WATER ON EARTH

THIRST VIDEO http://www.slideshare.net/jbrenman/thirst

THE HYDROSPHEREHydrosphere: 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)

SALTWATER 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 waterOceans35 g salt/kg of water

How many oceans are currently recognized today??!!

FRESHWATERFreshwater:

< 1 g salt/kg of waterONLY 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

FRESHWATER RESOURCES Most freshwater is

frozen at the polar ice caps!!

Glaciers are masses of ice and snow that move slowly over the Earth’s surface.

WHERE’S THE WATER?

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

FRESHWATER RESOURCES 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.

AQUIFERS Underground permeable rock or

sediment that contains water Particles in ground act like filter to water!!

GROUNDWATER 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 WATER TABLE & SATURATION ZONE

GROUNDWATER TO THE SURFACE VIA… 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

MAN-MADE WELL

ARTESIAN WELL & SPRING

GEYSER IN ICELAND – YOUTUBE CLIP http://www.google.com/url?q=http://

www.youtube.com/watch%3Fv%3DW-daow-LojM&sa=U&ei=n65CT8aeApDcgge2o63lCw&ved=0CCgQtwIwAg&usg=AFQjCNEpLlDlSzVPx4aS-Tu3nfBc1pCkKw

http://www.youtube.com/watch?v=tShhZvvIM84&feature=related

WATER CYCLE – QUICK REVIEW 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!!**