1. Changes to the Earth's Surface

2. Why is the Earth’s surface always changing?
It is constantly subjected to powerful forces like weathering, erosion, transportation and deposition.
Today we are going to review the processes that help to change the Earth’s surface.

3. How is Earth’s surface Changed?
Weathering
The breakdown of rock and other materials into smaller pieces.
Erosion
The removal of those smaller pieces of rock and soil.
Transportation
Movement of those pieces.
Deposition
Dropping off or depositing of those pieces to a new location.

4. Weathering
Weathering is the breakdown of rock and other materials into smaller pieces.
Rocks can be broken down by physical or chemical weathering.

5. 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.

6. 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.

7. Erosion
Erosion is the removal of those smaller pieces of rock and soil.
Erosion can be caused by:
Gravity
Wind
Rain
Waves
Glaciers melting or eroding themselves
Erosion works together with weathering and deposition.

8. Transportation
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

9. Deposition
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.

10. Weathering Erosion Transportation Deposition 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.
Weathering
Erosion
Transportation
Deposition

11. 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.

12. 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…