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Properties of Water

Properties of Water. Properties of Water. Only natural substance that exists as solid, liquid, and gas in temperatures normally found on Earth Freezing point = 0 o C (32 o F) Boiling point = 100 o C (212 o F). Properties of Water. Expands when it freezes More dense as a liquid than a solid

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Properties of Water

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  1. Properties of Water

  2. Properties of Water • Only natural substance that exists as solid, liquid, and gas in temperatures normally found on Earth • Freezing point = 0oC (32oF) • Boiling point = 100oC (212oF)

  3. Properties of Water • Expands when it freezes • More dense as a liquid than a solid • Density of water = 1 g/cm3 • Density of ice = 0.91 g/cm3

  4. Properties of Water • High specific heat • A lot of energy is needed to change its temperature. • Moderates air temperature

  5. Properties of Water • High surface tension • Cohesion • Adhesion

  6. Properties of Water • Universal Solvent • Dissolves many (not all) substances

  7. The Water Cycle

  8. The Water Cycle • Earth’s water supply is continuously recycled. • The overall process is powered by the Sun’s energy.

  9. Water Storage • Ocean • Most water on Earth • Glaciers • Most fresh water • Lakes • Ice/snow • Atmosphere

  10. How Water Enters the Atmosphere • Evaporation • Transpiration • Sublimation

  11. Forms of Precipitation • Rain • Sleet • Snow • Hail • Freezing Rain

  12. The Water Cycle • Once water reaches Earth’s surface as precipitation, it can: • Evaporate • Infiltrate • Run off

  13. The Water Cycle

  14. Runoff • Runoff is water flowing downslope along Earth’s surface. • Runoff may • reach a stream, river, or lake • evaporate • accumulate and eventually seep into the ground (infiltrate)

  15. Factors that affect Runoff • Vegetation • Rate of Precipitation • Soil Compaction • Slope

  16. Surface Water Movement

  17. Watersheds and Divides • Watershed • all of the land area whose water drains into a stream system • stream system • large river and all its tributaries

  18. NC Watersheds NC has 12,200 km of rivers and streams

  19. Stream Development

  20. Moving Water Carves a Path • Must have an adequate supply of water • Stream begins at headwaters

  21. Youthful Rivers • Steep gradient (slope) • Narrow channel (downcutting) • Channel is V-shaped • Fast moving • Moves all sediment sizes • No floodplain • Rapids and waterfalls • More erosion than deposition

  22. Youthful River

  23. Mature Rivers • Channel is U-shaped • Medium velocity • Moves many sediment sizes - not boulders • Small floodplain • Meanders begin to form • Erosion and deposition occur • Carries more sediment

  24. Mature River

  25. Old Rivers • Very shallow gradient • Channel is wider than deep • Slow moving • Moves small-sized sediments • Wide floodplain • Meanders are abundant • Large discharge

  26. Old River

  27. Meandering Streams • In a curve, the greatest speed is along the outside of the curve. • Erosion occurs along the outside of the curve. • Deposition occurs along the inside of the curve.

  28. Meandering Streams

  29. Work of Streams • A stream’s load includes all the materials that the water in a stream carries. • solution (dissolved) • suspension (carried) • bed load (pushed)

  30. Work of Streams • Erosion • The ability of a stream to erode materials depends on its velocity. • Abrasion • Grinding • Dissolving

  31. Lakes and Wetlands

  32. Lakes and Freshwater Wetlands • A lake is a depression that collects and holds water. • Reservoirs are lakes made for storing water for a community’s use.

  33. Origins of Lakes • Natural lakes form in different ways. • Oxbow lakes: streams cut off meanders and leave isolated channels of water. • Lakes can form when stream flow becomes blocked by sediment from landslides.

  34. Origins of Lakes • Natural lakes form in different ways. • Cirque lakes: depressions left by valley glaciers fill with water. • Kettle lakes: blocks of ice left by melting glaciers melted. • Some lakes are formed when the ceilings of limestone caverns collapse leaving depressions that fill with water.

  35. Lakes Undergo Change • Lakes are temporary water-holding areas. • Eventually lakes fill in with sediment and become part of a new landscape.

  36. Freshwater Wetlands • A wetland is a land area that is covered with water for a large part of the year. • Wetlands include environments commonly known as bogs, marshes, and swamps.

  37. Freshwater Wetlands • Bogs receive their water from precipitation and tend to be rich in peat moss.

  38. Freshwater Wetlands • Marshes frequently form along the mouths of streams and in areas with extensive deltas. • Marshes have tall grasses.

  39. Freshwater Wetlands • Swamps are low-lying areas often located near streams. • Swamps have shrubs and trees.

  40. Freshwater Wetlands • A filtering system • Pollutants • Sediments • Pathogenic bacteria • Habitats • Migratory birds • Water birds • Endangered species

  41. Freshwater Wetlands • From the late 1700s to the mid 1980s, the continental United States lost 50 percent of its wetlands.

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