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SCIENCE NOTES - LANDFORMS
LESSON 1
What Makes the Crust Move?
- Earthquakes are related to cracks in the crust called faults.
- A seismograph records the motion of an earthquake.
- Most of the time the crust layer is moving very slowly.
- Plate Tectonics – When the crust breaks into pieces from the
movement of the hot mantle, it creates plates.
What Forces Act on the Crust?
- Tension stretches or pulls apart the crust.
- Compression squeezes or pulls together the crust.
- Shear twists or tears the crust.
- Mountains made up of crumbled or folded up layers are called fold
mountains.
- Mountains created by movement along a fault are called fault-block
mountains.
What Other Forces Shape Earth’s Surface?
- Weathering is the breaking down of the materials of the Earth’s crust
into smaller pieces.
- Erosion is the picking up and carrying away of the pieces.
- The greatest cause of erosion is water from rainfall (precipitation).
- Physical Weathering – This is when the crust is exposed to water, air,
and temperature changes.
- Chemical Weathering – This is when chemicals in the air or rain react
to cause changes.
How Can Wind and Ice Erode Rock?
- Wind can push things along with it, but not as hard as water.
- Ice from a glacier can tear and erode the ground below it while it
moves.
Where do Eroded Rocks Go?
- When whatever is causing the erosion stops moving, it stops carrying
the bits of rock.
- Deposition is the dropping off of the eroded rocks.
- This causes rocks to build up at the end of rivers and shorelines.
What Forces Shape the Moon’s Surface?
- No earthquakes or volcanoes and no air or water to cause erosion.
- Weathering and erosion only occur from meteorites hitting the
surface.