1. External Forces Shaping the Earth

2. Weathering vs. Erosion  Weathering - physical and chemical processes that change the characteristics of rock on or near the earth’s surface. The final result of weathering is sediment.  Mechanical weathering - changes in physical composition…drilling and blasting to build roads.  Chemical weathering - changes in chemical composition…bike left outside in the rain  Weathering - physical and chemical processes that change the characteristics of rock on or near the earth’s surface. The final result of weathering is sediment.  Mechanical weathering - changes in physical composition…drilling and blasting to build roads.  Chemical weathering - changes in chemical composition…bike left outside in the rain

4. Erosion  Erosion occurs when weathered material (sediment) is moved by wind, water, ice, or gravity.  Glaciers, waves, running water, or blowing winds cause erosion by grinding rock into smaller pieces.  Types of erosion:  Water  Wind  glacial  Erosion occurs when weathered material (sediment) is moved by wind, water, ice, or gravity.  Glaciers, waves, running water, or blowing winds cause erosion by grinding rock into smaller pieces.  Types of erosion:  Water  Wind  glacial

5. End Result?  What do the processes of weathering and erosion contribute to? Forming soil!  Soil is the loose mixture of weathered rock, organic matter, air, and water…fertile soil is a certain mixture of these ingredients, along with climate and time.  What do the processes of weathering and erosion contribute to? Forming soil!  Soil is the loose mixture of weathered rock, organic matter, air, and water…fertile soil is a certain mixture of these ingredients, along with climate and time.

6. Seasons  What causes changes in the seasons?  The tilt of the earth’s axis as it revolves around the sun  Solstices - summer and winter  Equinox - spring and autumn  What causes changes in the seasons?  The tilt of the earth’s axis as it revolves around the sun  Solstices - summer and winter  Equinox - spring and autumn

8. Weather vs Climate  What is weather?  What does the weather report consist of on the nightly news?  What is weather?  What does the weather report consist of on the nightly news?

9. Weather  Weather is the condition of the atmosphere at a particular location and time.  What causes weather?  Water vapor  Cloud cover  Landforms and bodies of water  Elevation  Air movement  Weather is the condition of the atmosphere at a particular location and time.  What causes weather?  Water vapor  Cloud cover  Landforms and bodies of water  Elevation  Air movement

10. Climate  Climate is the term for weather conditions at a particular location over a long period of time…weather patterns.  Specific temperature and rainfall or average temperature and rainfall?  Climate is the term for weather conditions at a particular location over a long period of time…weather patterns.  Specific temperature and rainfall or average temperature and rainfall?

11. What affects Climate?  Wind and Ocean currents - help distribute the sun’s heat  Zones of latitude - low or tropical, middle or temperate, and high or polar  Elevation - as altitude increases, the air temperature drops about 3.5˚F for every 1,000 feet…Mt. Kilimanjaro  Topography - landforms and bodies of water can facilitate and serve as barriers in distributing heat, moisture, etc.  Wind and Ocean currents - help distribute the sun’s heat  Zones of latitude - low or tropical, middle or temperate, and high or polar  Elevation - as altitude increases, the air temperature drops about 3.5˚F for every 1,000 feet…Mt. Kilimanjaro  Topography - landforms and bodies of water can facilitate and serve as barriers in distributing heat, moisture, etc.

12. Can climates change over time?  Yes! Some climate changes are natural and others are a result of human activity on earth.  El Nino - a natural change in climate  Global Warming - most likely the result of human activity…the greenhouse effect  Yes! Some climate changes are natural and others are a result of human activity on earth.  El Nino - a natural change in climate  Global Warming - most likely the result of human activity…the greenhouse effect