Transcript 1 - MrsGordonsWiki

Weathering and
Erosion
By: ___________
Table of Contents
1. Word Bank
2. What I Know
pg. 1
pg. 6
Word Bank
1
1. weathering – natural process through
which rocks or other materials are
broken down into smaller pieces
2. erosion – the process through which
weathered rock or soil is moved from
one place to another.
3. glacier – a large mass of slowly flowing
ice
Word Bank
2
4. deposition - the process by which
eroded materials are dropped off in
another place.
5. meanders – gentle curves that
sometimes form in rivers with slow
moving water
6. sediment – particles of soil and rock that
are carried along by water or wind
Word Bank
7 floodplain – a place that is easily flooded when
river water rises.
3
What I Know
6
The shape of the Earth can change over time by
weathering (breaking down into smaller pieces) and
eroding (moving broken pieces from one place to
another).
3 forms of erosion:
1. by glacier
2. by water
3. by wind
What I Know
6
Weathering:
Physical – caused by temperature changes, pushing,
pulling or rubbing.
Examples of Physical Weathering:
1. when water freezes in cracks of rocks.
2. trees grow up through cracks in rocks
(on a cliff)
3. rocks fall off the cliff and break other
rocks on the way down.
What I Know
6
Weathering:
Chemical Weathering occurs when chemicals break
down rock.
Examples of Chemical Weathering:
1. statue changes color (acid rain)
Acid rain wears away stone and metals
Acid rain forms when gases from factories
enter the air and combine with rain drops.
2. forming of a cave (chemicals in groundwater
break up underground rock)
What I Know
11
Land can be eroded by gravity, glaciers,
running water, waves, or wind.
Erosion:
By Gravity :
Mudslide – the movement of a large amount of mud down a
slope; when rain makes soil on a slope so heavy that it
cannot stay in place on the slope.
Landslide – the movement of a large amount of rocks and
soil; may occur after an earthquake or volcanic eruption as
these events loosen rocks and soil enough to be affected by
gravity.
Plants can help prevent erosion from gravity
What I Know
11
Erosion:
By Glaciers :
 Glaciers form in cold areas where snow piles up and freezes.
 Water freezes in cracks in the rock, and as the glacier moves it
carries away weathered pieces of rock
 Rocks and flowing ice also wear away dirt and rock along the sides of
the glacier.
What I Know
11
Erosion and Deposition:
Erosion and deposition work together to change the shape
of Earth’s surface.
As sediment is deposited, new land is formed.
By running water:
Water moves more rapidly on the outside of a
meander; while moving slowly around the inside.
Rivers with faster moving water tend to follow
straight paths with deeper channels and steeper
banks; slower moving waters have low banks and
shallow channels with curvy paths.
As water runs down a hill, it washes away soil and
erodes rock.
What I Know
11
Erosion and Deposition:
By waves:
Waves can erode the shoreline and move sand and rocks
further out to sea or down the beach to the side.
When waves hit an area with 3 sides, the water erodes the
sides. As this happens the rock forms an arch.
When waves wash sand off the beaches, this sand may be
deposited into the water rather than back on the beach.
• Eventually these sand deposits will build to make a sandbar.
What I Know
12
Erosion and Deposition:
By wind:
Wind can wear away rock and make them smooth.
Wind can move sediment from one place to another
(erosion)
Sediment continues to erode with the wind until the wind
slows down or stops. Then it is deposited.
A dune forms when wind erodes sand and deposits it along
the back of the beach.
A dune forms in the direction that the wind usually blows.