Transcript Changes_to_the_Earth`s_Surface

Why is the Earth’s surface
always changing?
• It is constantly
• Today we are
subjected to
going to review the
powerful forces like
processes that
weathering,
help to change the
erosion,
Earth’s surface.
transportation and
deposition.
How is Earth’s surface Changed?
The breakdown of rock and other
materials into smaller pieces.
The removal of those smaller
pieces of rock and soil.
Movement of those pieces.
Dropping off or depositing of
those pieces to a new location.
• Weathering is the breakdown of rock
and other materials into smaller pieces.
• Rocks can be broken down by physical
or chemical weathering.
Physical Weathering
Physical weathering is the cracking,
breaking up, and grinding down of rocks into
smaller pieces. This type of weathering is
caused by a number of different factors.
– Changing temperatures cause rocks to crack and
flake.
– Ice splits rocks open.
– Living things dig or pry open rocks.
– Gravity causes rocks to fall and shatter
– Abrasion breaks down rocks with solid particles
like sand.
Chemical Weathering
Chemical weathering is the breakdown of
rocks as a result of a change in their mineral
composition.
» Minerals can either be added to or removed from
rocks.
» Acid rain, plant acids, carbonation, and oxidation can
cause chemical weathering.
» they can dissolve minerals that hold rocks together
by chemically changing the rock and causing it to
crumble.
• Erosion is the removal of those smaller
pieces of rock and soil.
• Erosion can be caused by:
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Gravity
Wind
Rain
Wind
Waves
Glaciers melting or eroding themselves
• Erosion works together with
weathering and deposition.
•Transportation or transport is the
movement of the smaller pieces of rock
after erosion has happened.
•Transportation or transport of rock
happens the same way erosion does:
•wind, rain, waves, gravity, running water (streams and rivers) and
melting glaciers
•Deposition is the dropping off or
depositing of the small pieces of rock in
a new location.
•The rock pieces are deposited in the same
way as erosion and transport-by rivers and
streams, waves, wind, storms, gravity and
glaciers.
•Sometimes the new location is nearby and
sometimes it is thousands of miles away.
Let’s review…………………
•
the breakdown of rock and other
materials into smaller pieces
•
the removal of those smaller pieces of
rock and soil.
•
the movement of the smaller pieces of
rock after erosion has happened
• the dropping off or
depositing of the small
pieces of rock in a new
location.
The two most important concepts in
geology are…
• Weathering and Erosion!!! They affect
the Earth’s surface and are very important
in the formation of soil.
How can we help?
• Over time, humans have learned techniques (ways to) to
minimize (decrease) the effects of these three forces
(erosion, transport and deposition) of nature to
preserve land formations (mountains, hills and valleys)
and soil (dirt), which is a valuable resource.
• Soil erosion can be slowed down by plant growth
covering bare soil.
• This is accomplished in two ways: 1) the roots hold the
soil in place, and 2) the vegetation absorbs the impact of
the water hitting the ground, lowering the velocity with
which the water enters the soil.
• Let’s check it out…