Changing land

Changing land

erosion, weathering, and deposition

Landforms

• Change over time.

• Mountains start out with sharp, jagged peaks. Over time, the slopes will become smoother and rounder.

• This happens because rocks break away and move to different places.

Weathering, erosion, and deposition

• Weathering: breaking down of rock and land from wind, water, or other natural events.

• Erosion: The movement of rock and land to a new place.

• Deposition: The deposit, or putting down, the rock and land in a new place.

• Weathering happens first, then erosion, then deposition.

Weathering

• By wind: wind grinds against rocks, slowly wearing them down.

• By water: water grinds agains rocks, slowly wearing them down.

• By ice: water travels into cracks in the rock. It then freezes, and expands, and then melts. This process happens over and over again, eventually breaking the rock a part.

• By gravity: rocks fall and split, or fall on each other.

• By living things: Animals can break down rock, humans can as well. Even plants with roots can effect rocks.

Open Ended

What is one reason why rocks get weathered?

Erosion

• The movement of rock and land to a new place.

• Many things that cause weathering, also cause erosion.

• Wind can carry small rock particles from a cliff to a new place.

• Water can carry small sediment (bits of rock and land) to a new place.

• Ice in a glacier can break off rock and carry it to a new place.

• Human beings: cutting trees down would allow the soil to wash away more easily. Less trees means less vegetation, means animals won't eat, and it could start a really scary cycle!!!

Multiple Choice

Erosion is...

• the breaking down of rock and land.

• the depositing, or putting down of rock and land in a new place.

• the movement of rock and land to a new place.

Deposition

• Eventually wind, water, ice and gravity put the rock and land pieces down. This is called deposition (deposit means putting it down).

• Over time this can build up new landforms.

• Small rocks are deposited after the wind dies down. This happens over and over again. Eventually new beaches and sand dunes are formed.

• When glaciers melt, pieces of rock and land are deposited.

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Poll

What is deposition?

• The movement of rock and land to a new place.

• The breaking down of rock and land,

• The putting down of rock and land in a new place.

Multiple Select

What are two examples of erosion?

• wind breaking down rock

• a glacier break a part rock and moving it to a new palce

• Water running over rocks making them smoother.

• Water washing away soil from a hillside in the mountains.