1. Weathering and Erosion Properties of Earth's Water and Atmosphere SOL 6.5

2. Weathering= the process that breaks down rock and other substances at Earth's surface. Weathering= the process that breaks down rock and other substances at Earth's surface.  Agents of weathering= heat, cold, water, ice, as well as oxygen and carbon dioxide in the atmosphere.

3. Examples of Weathering: Examples of Weathering: Mountains wearing away over time Mountains wearing away over time Bicycles rusting Bicycles rusting Paint peeling Paint peeling Sidewalks cracking Sidewalks cracking Formation of potholes in road Formation of potholes in road

4. The forces of weathering break rocks into smaller and smaller pieces. Then the forces of erosion carry those pieces away. The forces of weathering break rocks into smaller and smaller pieces. Then the forces of erosion carry those pieces away.

5. Erosion= the movement of rock particles by wind, water, ice, or gravity. Erosion= the movement of rock particles by wind, water, ice, or gravity. Weathering and erosion work together continuously to wear down and carry away the rocks at Earth's surface. Weathering and erosion work together continuously to wear down and carry away the rocks at Earth's surface.

6. There are 2 types of weathering and they work together: There are 2 types of weathering and they work together: Mechanical weathering= the type of weathering where rock is physically broken down into smaller pieces. Mechanical weathering= the type of weathering where rock is physically broken down into smaller pieces. How it happens: by freezing and thawing (ice wedging), release of pressure, growth of plants, actions of animals, and abrasion (grinding away of rock by water, ice, wind or gravity). How it happens: by freezing and thawing (ice wedging), release of pressure, growth of plants, actions of animals, and abrasion (grinding away of rock by water, ice, wind or gravity). Produces smaller pieces of the same exact material. Produces smaller pieces of the same exact material. This type of weathering works slowly, but over time it will eventually wear away whole mountains. This type of weathering works slowly, but over time it will eventually wear away whole mountains.

7. Ice Wedging

8. Chemical Weathering=process that breaks down rock through chemical changes. Chemical Weathering=process that breaks down rock through chemical changes. How it happens: by water, oxygen, carbon dioxide, living organisms and acid rain. How it happens: by water, oxygen, carbon dioxide, living organisms and acid rain. Produces rock products that have a different makeup from the rock they came from. Produces rock products that have a different makeup from the rock they came from.  Example: chemical weathering of granite changes the minerals that make up the granite into something else. Chemical weathering creates holes and soft spots in rock so that it breaks apart more easily. Chemical weathering creates holes and soft spots in rock so that it breaks apart more easily.

9. Checkpoint How do you think physical and chemical weathering work together to wear down rock? How do you think physical and chemical weathering work together to wear down rock?

10. The most important factors that determine the rate at which weathering occurs are the type of rock and climate. The most important factors that determine the rate at which weathering occurs are the type of rock and climate. Whether the material easily dissolves in water or not. Whether the material easily dissolves in water or not. Whether the material is permeable. Whether the material is permeable. Wet, hot climates vs. dry, cold climates. Wet, hot climates vs. dry, cold climates.

11. Water is the most important agent of chemical weathering because it causes the most chemical weathering to happen. Water is the most important agent of chemical weathering because it causes the most chemical weathering to happen. Water weathers rock by dissolving it. When a rock or other substance dissolves in water, it mixes uniformly throughout the water to make a solution. Water weathers rock by dissolving it. When a rock or other substance dissolves in water, it mixes uniformly throughout the water to make a solution.

12. Speaking of Water... The Earth’s surface is made up of ¾ water. The Earth’s surface is made up of ¾ water. Only 3% of the Earth's water is freshwater; the other 97% is salt water. Only 3% of the Earth's water is freshwater; the other 97% is salt water. Most of this freshwater is found near the North and South Poles in glaciers, leaving only 1% of it usable for humans. This makes freshwater a limited resource which we need to conserve. Most of this freshwater is found near the North and South Poles in glaciers, leaving only 1% of it usable for humans. This makes freshwater a limited resource which we need to conserve.

13. We need water! Water is important to human life as well as other living organisms. Water is important to human life as well as other living organisms. Our body is made up of more than 50% water. Our body is made up of more than 50% water. Water is used to grow food and is important for public health. Water is used to grow food and is important for public health.

14. Groundwater A lot of water is found underground in an aquifer. An aquifer is any underground layer of rock or sediment that holds water. A lot of water is found underground in an aquifer. An aquifer is any underground layer of rock or sediment that holds water. Some underground water eventually makes it to the surface in springs, streams and ponds. Some underground water eventually makes it to the surface in springs, streams and ponds. Humans can also help bring water underground to the surface through the use of wells. About half the people in the United States get their water this way. Humans can also help bring water underground to the surface through the use of wells. About half the people in the United States get their water this way.

15. Other ways to get water... An aqueduct carries water from one place to another. An aqueduct carries water from one place to another. This aqueduct, the Pont du Gard in France, was built by the Romans more than 2,000 years ago. This aqueduct, the Pont du Gard in France, was built by the Romans more than 2,000 years ago.

16. Since we have a limited amount of freshwater on Earth and an abundant amount of salt water, we use the process of desalination. Since we have a limited amount of freshwater on Earth and an abundant amount of salt water, we use the process of desalination. The process of desalination causes the water to evaporate from the saltwater creating usable freshwater. This method creates a large amount of freshwater. The process of desalination causes the water to evaporate from the saltwater creating usable freshwater. This method creates a large amount of freshwater.

17. Remember Water's Specific Heat...? Water's specific heat allows large bodies of water to slowly absorb and release heat, making it stay warmer longer than land. Water's specific heat allows large bodies of water to slowly absorb and release heat, making it stay warmer longer than land. This allows the climate near areas of large bodies of water (oceans) to be milder in both the summer and winter. This allows the climate near areas of large bodies of water (oceans) to be milder in both the summer and winter.

18. Atmosphere of Earth Earth's atmosphere is made up of mostly Nitrogen. Earth's atmosphere is made up of mostly Nitrogen. 78% nitrogen 78% nitrogen 21% oxygen 21% oxygen 1% other gases 1% other gases

19. Soil forms as rock (exposed bedrock) is broken down by weathering and mixes with other materials on the surface. Soil forms as rock (exposed bedrock) is broken down by weathering and mixes with other materials on the surface. It is a mixture of rock particles, minerals, decayed organic material (humus), air, and water. It is a mixture of rock particles, minerals, decayed organic material (humus), air, and water.

20. A soil horizon, is a layer of soil that differs in color and texture from the layers above or below it. A soil horizon, is a layer of soil that differs in color and texture from the layers above or below it. Topsoil= crumbly and dark brown. Composed of humus, clay and other minerals. Subsoil=composed of clay and other particles.

21. In the United States alone, differences in climate and local bedrock have led to the formation of thousands of different types of soil. In the United States alone, differences in climate and local bedrock have led to the formation of thousands of different types of soil. The different types of soil are classified by: The different types of soil are classified by:  climate of the region it is found  the different plants living in that region  its composition (rocky, sandy, or full of clay).

22. Soil Types Foldable Tundra Soils Tundra Soils Northern forest soils Northern forest soils Prairie Soils Prairie Soils Mountain Soils Mountain Soils Southern Forest Soils Southern Forest Soils Desert Soils Desert Soils Tropical Soils Tropical Soils

23. Tundra Soils Forms where it is cold year round Forms where it is cold year round Thin soil with little humus. Thin soil with little humus.

24. Land is a precious resource. Land is a precious resource. “They don't make it anymore.” --Mark Twain “They don't make it anymore.” --Mark Twain Land makes up only a ¼ of the Earth's surface. Land makes up only a ¼ of the Earth's surface. All the people on Earth must share this limited amount of land to produce food, build shelter, and obtain other resources. All the people on Earth must share this limited amount of land to produce food, build shelter, and obtain other resources.

25. Northern Forest Soil Form in cool, wet climates Form in cool, wet climates Can be thick and fertile or thin with little humus. Can be thick and fertile or thin with little humus.

26. Prairie Soils Form in cool, dry climates of grasslands Form in cool, dry climates of grasslands Topsoil is thick and rich in humus Topsoil is thick and rich in humus

27. Mountain Soils Topsoil often thin because cold temperatures slow chemical weathering and erosion causes soil loss. Topsoil often thin because cold temperatures slow chemical weathering and erosion causes soil loss.

28. Southern Forest Soils Form in warm, wet climates Form in warm, wet climates May be low in humus May be low in humus

29. Tropical Soils Form in wet, tropical climates Form in wet, tropical climates Often low in humus and minerals Often low in humus and minerals

30. Three uses that change the land are agriculture, development, and mining. Three uses that change the land are agriculture, development, and mining. Soil is one of the Earth's most valuable resources because everything that lives on land depends directly or indirectly on soil and there is a limited supply of fertile soil. Soil is one of the Earth's most valuable resources because everything that lives on land depends directly or indirectly on soil and there is a limited supply of fertile soil. less than 1/8 of soil on Earth is suitable for farming less than 1/8 of soil on Earth is suitable for farming Soil can be lost or damaged. Soil can be lost or damaged.

31. Ways soil can be lost/damaged: Ways soil can be lost/damaged: Soil can be exhausted or lose its fertility by over farming. Soil can be exhausted or lose its fertility by over farming. Soil can be polluted by mining or chemical spills. Soil can be polluted by mining or chemical spills. It can be lost to erosion by water and wind. It can be lost to erosion by water and wind. Desertification can happen in places with little rainfall (Plants die which causes wind to carry soil away), or in places where overgrazing or clear cutting has occured. Desertification can happen in places with little rainfall (Plants die which causes wind to carry soil away), or in places where overgrazing or clear cutting has occured.  Example: the “Dust Bowl”

32. Soil Conservation is the management of soil to prevent its destruction. Soil Conservation is the management of soil to prevent its destruction. Contour plowing= practice of plowing fields along the curves of a slope which helps to slow the runoff of excess rainfall and prevents the washing away of soil. Contour plowing= practice of plowing fields along the curves of a slope which helps to slow the runoff of excess rainfall and prevents the washing away of soil. Conservation plowing= disturbs the soil and its plant cover as little as possible. Dead weeds and stalks of the previous year's crop are left in place. Conservation plowing= disturbs the soil and its plant cover as little as possible. Dead weeds and stalks of the previous year's crop are left in place. Crop rotation= a method that helps preserve the soil's fertility. A farmer plants different crops in a field each year. Sometimes the fields are left fallow or unplanted. Crop rotation= a method that helps preserve the soil's fertility. A farmer plants different crops in a field each year. Sometimes the fields are left fallow or unplanted.

34. Windbreaks and Terracing

35. Land reclamation= the process of restoring an area of land to a more natural, productive state. Land reclamation= the process of restoring an area of land to a more natural, productive state. Restoring lands for agriculture Restoring lands for agriculture Restore habitats for wildlife Restore habitats for wildlife It is harder to restore damaged land and soil than it is to protect them in the first place. It is harder to restore damaged land and soil than it is to protect them in the first place.