New Text: Earth’s Waters

1. New Text: Earth’s Waters Standards: 4.3.7.B – Explain the distribution & management of natural resources (water) 3.3.6.A4 – Describe how water on Earth cycles in different forms & locations

2. Water IS everywhere! longevity.about.com/.../Water-for-Anti-Aging.htmRemove frame

3. It’s here… www.mommablogsalot.com/2008/10/09/imagine/ Remove frame

4. and here… www.interiorseas.com/

5. and here – just to show a few places! www.en.wikipedia.org/polar_bear

6. When there isn’t any water…

7. 44. Chp. 1 – The Water PlanetUses of Water • Household and personal use • Agriculture - irrigation • Transportation • Recreation • Industry • Metabolism – chemical reactions inside living organisms • Food

8. Household and Personal

9. Agriculture

10. Transportation

11. Recreational

12. Industrial

13. Metabolism

14. Food

15. 45. Distribution of Water • Approximately 75% of Earth is covered with water. • Thus, the Earth is called the “Water Planet”. • Of all the water on Earth, 3% is freshwater and 97% is saltwater. • Most of the Earth’s freshwater is in the frozen form as ice.

16. 46. Usable Freshwater is Limited Of all the freshwater on Earth, 76% is in the solid form, so people can’t use it.

17. 47. Water’s Chemical Structure • Chemical formula is H2O • One molecule of water consists of 2 hydrogen atoms and 1 oxygen atom

18. 48. Water is a Polar Molecule • In a water molecule the oxygen end has a negative charge and the hydrogen end has a positive charge • These opposite charges attract (just like the opposite poles of a magnet); we say water is “polar” • Polarity makes water molecules stick together as you seehere

19. 49. “Sticky” water takes on special properties • Property 1 –molecules sticking together form a “skin” across the top of water which we call surface tension • This acts like an invisible net that can hold very light objects up!

20. Animation of Surface Tension Experiment • You will see how we can make a steel paper clip float on water • http://www.youtube.com/watch?v=9MBHf7j7bVs&feature=related

21. 50. (More Properties) • Property 2 – water molecules also stick to the walls of thin tubes or the fibers in cloth or paper to climb upwardusing capillary action (You do not have to copy the caption below.) Only in the narrow well does then man have hope of climbing up the walls! It’s the same for water…a thintube is required for capillary action.

22. Watch an Experiment on Capillary Action • You will see water climb its way out of a glass of water, go up & over a paper bridge, and then partially fill a second empty glass • http://www.youtube.com/watch?v=mdkeZbm0cCI

23. 51. (More Properties) • Property 3 – when water molecules use their “stickiness” to tug on other polar molecules in a solid, they can pull them out of fixed position to make them dissolve in water • This ability gives water the name: universal solvent; it dissolves ANYTHING ELSE that is also polar (charged) • Nonpolar substances (uncharged) like oil or wax will NOT dissolve in water

24. Watch an Animation of Water Molecules Dissolving Salt (NaCl) • Na has a positive charge on it which will be attracted to the negative oxygen end of water • Cl has a negative charge on it which will be attracted to the positive hydrogen end of water • http://www.youtube.com/watch?v=EBfGcTAJF4o

25. 52. The “State” of Water is Unique • WATER IS THE ONLY COMPOUND ON EARTH THAT EXISTS IN ALL THREE STATES: SOLID (ice), LIQUID (fresh & saltwater), AND GAS (water vapor).

26. 53. Changes in State • Adding heat will change the state of water as it speeds up the molecules to make them move more freely • SolidLiquid = Melting • LiquidGas (slowly) = Evaporation • LiquidGas (rapidly) = Boiling

27. Animation of Phase Changes in Water • Let’s see how adding heat will speed up water molecules and make them move more freely until the point where they have enough energy to “fly away” • http://mutuslab.cs.uwindsor.ca/schurko/animations/waterphases/status_water.htm

28. 54. Changes in State (cont’d) • Removing heat (cooling) can also change the state as the molecules slow down & get closer • GasLiquid = Condensation • LiquidSolid = Freezing

29. The Water Cycle – the continuous process by which water moves through the environment. www.commwater.com/water_cycle.htm Remove frame

30. Water Cycle Vocabulary: • 1) Precipitation – water that falls to Earth as rain, sleet, hail or snow • 2) Percolation – the trickling of water down through the soil • 3) Groundwater – water that has filled cracks in the soil and rock layers; used for well water • 4) Runoff - water that flows over the ground surface rather than sinking into the soil • 5) Evaporation – when water absorbs enough heat energy to escape from the water surface to become gaseous water vapor in the air • 6) Transpiration – when water inside of a plant absorbs enough heat energy to escape out tiny pores in the leaves to become gaseous water vapor • 7) Condensation – the cooling of water vapor back into liquid droplets • 8) Cloud – a place where water vapor collects and may later condense into rain, sleet, snow or hail when the temperature drops

31. Let’s view an animation of Plant Transpiration • http://www.youtube.com/watch?v=U4rzLhz4HHk

32. Source of Energy Question: What energy source drives the water cycle? Answer: The sun.

33. Take the “-ation” Quiz • Water becomes a gas - _ _ _ _ _ _ ation • Water vapor becomes a liquid – _ _ _ _ _ _ ation • Water seeps down into the soil– _ _ _ _ _ _ ation • Water escapes from plant leaves – _ _ _ _ _ _ _ _ ation • Water returns to Earth in the form of rain, snow, sleet, hail, or freezing rain – _ _ _ _ _ _ _ _ ation

34. Another Look at the Water Cycle through viewing this animated link:http://earthguide.ucsd.edu/earthguide/diagrams/watercycle/

35. Water Cycle Quiz (numbered items are NOT in order) cempaka.edu.my:8866/blog/sargunanathan/ Remove frame