Changes to Earth’s Surface

Science — Second Preparatory

Changes to Earth’s Surface

Erosion and deposition

Erosion→is the removal of broken material from its place by water, wind, ice and waves. Deposition is the dropping of this material in a new place when the speed of the carrying agent decreases.

Comparison aspect	Main idea	Example	Keywords
Water erosion	rain and rivers carry sand and silt and cut deep valleys	the Grand Canyon carved by the Colorado River in the United States	rainriverscarrysand
Wind erosion	wind carries grains of sand forms sand dunes and shapes desert rocks	—	carriesgrainssandforms
Deposition	when a river reaches the sea its speed falls and silt settles to form a delta. The Nile Delta was built by silt carried over thousands of years from the highlands of Ethiopia and Sudan	—	riverreachesspeedfalls

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