Transcript Earth Science - Effingham County Schools

Destructive Processes
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Weathering is the breakdown of rocks by the
action of rain, cold, snow, etc. at or near
Earth’s surface.
Mechanical weathering breaks rock into
smaller pieces without changing it
chemically.
Soil is the material in which most plants
grow.
Erosion is the movement of weathered rock
from place to place.
Water, wind, glaciers, and ocean waves are
agents of erosion.
Destructive process:
Erosion
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Desert pavement is a surface of only bare ground and large stones.
A groin a structure built at right angles to the beach.
A seawall is a structure built parallel to the shore.
Contour plowing is a method in which farmers plow across the sides of hills
instead of down their slopes.
• Terracing is a method in which farmers plant crops on terraces built on
hillsides.
• Storm drain management is a system of drains that prevents flooding during
heavy rainstorms.
Destructive processes: Glaciers
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Sea stacks are pillars of stone in the sea that form from headlands.
Headland is a point of land that juts out into the ocean.
To form a Sea arch, waves first carve away softer rock in the headland.
Gravity is a force that pulls all objects toward each other.
The sudden movement of rocks and soil down side of a hill is called a
landslide.
Destructive Process: Volcanoes &
Earthquakes
• A volcano Is an opening in earth’s surface that
lets hot, melted rock and gases escape. When
erupted the mountain can be destroyed of
changed.
• The shaking of the ground is an earthquake.
This happens when the earth’s crust shifts at a
fault. Wide cracks may open in the ground and
sometimes even destroy buildings, roads and
bridges.
Constructive Process
• Deposition is the dropping of sediment or particles by water, wind,
or ice.
• A delta is a deposit of sediment that builds up at a rivers mouth a
flat piece of land.
• Floodplain is when the deposit of a sediment forms a wide, flat
area of land.
• Longshore current is a current that moves parallel to the shore.
Continued………
• Barrier island is a long, narrow island that forms along the
coast.
• A sand dune is a hill of sand deposited by wind.
• A moraine is a ridge of sediment and rock left behind
when a glacier melts.
• A dam is a structure built across a river to control its flow.
Controlling Processes that change the land
• A levee is a raised band of earth built along the edges of a
river to prevent flooding.
• Beaches that erosion has eaten away are reclaimed. Sands
from the ocean or nearby rivers are placed on the beach to
rebuild it. This is called beach nourishment.
Living with earthquakes and volcano
• Seismologists study earthquakes.
• Seismologists study seismic waves, which are
waves of energy that travel through Earth’s
crust.
• Seismographs measure and record seismic
waves.
• A seismogram is the record made by a
seismograph. Scientist study seismograms to
find out the size of an earthquake. It also helps
them to figure out where faults exist in Earth’s
crust.
•A tsunami is a huge
wave caused by an
earthquake under the
ocean.