1. + H 2 the Izz O! Water

2. + Water: H2O About 70% of the Earth’s surface is covered in water Can be: Ice, Liquid, or Vapor

3. + Fresh Vs. Salt Water The Earth has a lot of water, but land ecosystems, humans, and agriculture need fresh water which makes up only 0.1% of the total water available. Therefore, problems of water scarcity are abound.

4. + World’s Water System A. World’s total supply of water B. Fresh water (2.5%), but most is underwater or ice: so it can’t be used! C. Tiny dot is the 0.1% that is available A B

5. + Water, water everywhere, but not a drop to drink! We don't get to use most of the Earth’s water. At present, only 0.01% of all that water can be used by us. Available water is not always where we would like it to be!

6. + Examples… Water shortages in Saskatchewan, Alberta, and Manitoba Hot, dry summer in California Flooding along the Saint John River in New Brunswick Drought in Somalia and Ethiopia Cold, wet summer in Newfoundland Desertification in African countries

7. + The Water Cycle ‘Just go with the flow!’

8. + The Water Cycle The limited amount of Earth’s water keeps going around and around in what we call the water cycle. The water cycle is also known as the hydrologic cycle. The water cycle is made up of four main parts: evaporation (and transpiration), condensation, precipitation, and collection.

9. + The basic cycle consists of water rising to the atmosphere through transpiration and evaporation and leaving it through condensation and precipitation.

10. + The Hydrologic Cycle

11. + Evaporation Evaporation is when the sun heats up water in puddles, rivers, lakes, or the ocean and turns it into vapor. The water vapor leaves the puddle, river, lake or ocean and goes into the air. Water is in a gaseous state if it has evaporated.

12. + Evaporation

13. + Humidity The amount of water vapor in the air is humidity. The amount of water vapor air can hold increases with rising temperatures and decreases with lowering temperatures. Think about it! South America: Hot and Humid, Canada: Cold and Dry

14. + Transpiration People perspire and plants transpire. Transpiration is the process by which plants lose water out of their leaves.

15. + Condensation Condensation is the process by which water vapor in the air gets cold and changes back into liquid.

16. + Condensation… If droplets form in the atmosphere; the result is fog or mist. Masses of fog or mist in the distance are seen as clouds. If droplets form on the cool surfaces of vegetation the result is dew. If the temperature is below freezing the droplets form directly into ice crystals making snow or frost.

17. + Important Fact! Evaporation and condensation result in the natural purification of water. When water evaporates only the water molecules leave the surface; salts and other solids in solution remain behind. The condensed water is purified - except as it picks up pollutants in the air.

18. + Precipitation Precipitation occurs when too much water has condensed and 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.

19. + 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 soak into the earth and become part of the ground water …or it may run over the soil and collect in the oceans, lakes or rivers where the cycle starts all over again.

20. + Collection… As precipitation hits the ground, it may follow either of two pathways: 1. it may soak into the ground, known as infiltration, or it may 2. run off the surface, which we call runoff.

21. + Infiltration vs. Run-off InfiltrationRun-off

22. + Runoff Runoff flows over the ground into streams and rivers, which makes their way to the ocean or inland seas. All the land area that contributes water to a particular stream or river is known as the watershed for that stream or river.