Science: Erosion, Weathering, and Deposition
How Earth's surface changes over time
Science: Erosion, Weathering, and Deposition
How Earth's surface changes over time
Earth Science - Grade 6-8
- 1
Define weathering in your own words.
Think about what happens to rock before it gets moved anywhere else.
Weathering is the process of breaking down rock into smaller pieces at or near Earth's surface. - 2
Define erosion in your own words.
Erosion is the movement of weathered rock, soil, or sediment from one place to another by water, wind, ice, or gravity. - 3
Define deposition in your own words.
This happens after sediment stops being carried.
Deposition is the process in which transported sediment is dropped and settles in a new location. - 4
A rock cracks after water seeps into it, freezes overnight, and expands. Is this weathering, erosion, or deposition? Explain.
This is weathering because the rock is being broken apart in place by freezing and expanding water. - 5
A river carries sand and small pebbles downstream during a storm. Is this weathering, erosion, or deposition? Explain.
Focus on the word carries.
This is erosion because the river is moving sediment from one place to another. - 6
At the mouth of a river, the water slows down and drops layers of mud and sand. Is this weathering, erosion, or deposition? Explain.
This is deposition because the river slows down and leaves the sediment behind in layers. - 7
Name two agents of erosion and give one example of how each can move sediment.
Common agents include water, wind, ice, and gravity.
Two agents of erosion are water and wind. Water can carry sand and rocks downstream, and wind can blow dust or sand from one place to another. - 8
Explain the difference between mechanical weathering and chemical weathering.
Mechanical weathering breaks rock into smaller pieces without changing its composition, while chemical weathering changes the minerals in the rock through chemical reactions. - 9
How can plant roots cause weathering?
Think about roots growing in tiny spaces.
Plant roots can grow into small cracks in rock and push the rock apart as the roots get larger, causing mechanical weathering. - 10
Why do larger sediments usually get deposited before smaller sediments when water slows down?
Larger sediments usually get deposited first because they are heavier and need more energy to stay moving, so they settle when the water slows down. - 11
Describe one landform created mainly by deposition and explain how it forms.
Examples include deltas, sand dunes, and beaches.
A delta is a landform created mainly by deposition. It forms when a river enters a larger body of water, slows down, and drops sediment over time. - 12
A steep hillside loses soil after heavy rain, and the loose material collects at the bottom of the slope. Identify one part of this event as erosion and one part as deposition.
The soil washing down the hillside is erosion because sediment is being moved. The loose material collecting at the bottom is deposition because the sediment is settling in a new place.