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A short class with Sarah and her students. The other ways are under More.
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Today we're delving into weathering, the first external process. What do we know about it?
Isn't weathering when rocks break down?
Exactly! Weathering can be physical or chemical. Who can give examples of each?
Physical would be like freeze-thaw cycles where water gets in cracks and expands.
Chemical could be rust or the dissolution of limestone in acidic water.
Great examples! And remember, weathering doesn't move material, but it prepares it for erosion. Let's take this knowledge further!
Now that we know how materials break down, let's talk about erosion. How does it differ from weathering?
Erosion actually moves the materials away, right?
Yes! It's the transportation of those weathered materials. Can anyone name the agents of erosion?
Water, wind, ice, and even gravity!
Perfect! And think about how powerful water can be over time. Let's discuss how erosion shapes landforms.
Finally, we can't forget about deposition! What happens during the deposition process?
That's when the materials that were transported are laid down somewhere else!
Exactly! This can lead to the formation of new landforms. Can anyone give an example of a landform created by deposition?
Deltas at the mouth of rivers, where sediment collects!
Right! So remember, weathering breaks down materials, erosion transports them, and deposition drops them off.
Weathering's breaking, Erosion's moving, Deposition's laying down, that's the groove.
Imagine a mountain rock, weathering under the sun and rain, breaks apart; water carries it to the river where it’s deposited at the delta, forming new land.
Remember WED: Weathering breaks down, Erosion takes away, Deposition lays down.
WED (Weathering, Erosion, Deposition) - Think of it as the process that creates new landscapes!
Term
What is weathering?
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Term
Define erosion.
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What occurs during deposition?
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External processes such as weathering, erosion, and deposition shape the Earth's landforms and landscapes.
This section details external (exogenic) processes, emphasizing how weathering, erosion, and deposition modify landforms. By understanding these processes, students can appreciate the dynamic nature of landscapes and their significance to human activities.
External processes, also known as exogenic processes, encompass the physical and chemical processes that occur on the Earth’s surface, leading to the transformation of landforms. This section intricately explores three major exogenic processes:
Weathering - This is the breakdown of rocks into smaller particles through biological, chemical, or physical means. There are two main types: physical weathering, which breaks rocks without altering their chemical composition, and chemical weathering, which involves changes in the minerals that comprise the rocks.
Erosion - This refers to the removal and transportation of weathered rocks and soil from one location to another. Various agents such as water, wind, and ice contribute to erosion, reshaping the landscape significantly over time.
Deposition - After erosion, materials are laid down or deposited in new locations, leading to changes in topography like the formation of deltas and riverbanks.
The interplay of these processes ultimately shapes various landforms including mountains, plains, plateaus, valleys, and deltas, which are vital for understanding both the natural environment and the impact human activities have on it.