Changing land

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: 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.

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.

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!!!

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.