1. Weathering & Erosion
Chapter 4 Lesson 3
Page 192

2. What is weathering? Answer: A
As rain falls on the cliffs of the Palisades in New Jersey, water trickles into the cracks and freezes. The ice will push the cracks further apart and parts of the rock will break off
This is just one example of Weathering
Weathering is the process through which rocks or other materials are broken down
Weathering is considered a DESTRUCTIVE process
Answer: A

3. What is weathering? Physical Weathering
This is caused by pushing, pulling, rubbing, or temperature changes
Water in the cracks of rock freezing
Trees and other plants can also grow into the cracks on a cliff and as their roots grow they can push the walls of the cracks further apart.
Gravity can pull pieces of rocks down a slope. As the rocks roll down and bump into each other
Wind can blow on exposed rocks. The winds pick up small particles of sand or dirt and rub against the rock (like sandpaper)
Water- as rocks are carried along in moving water they may bump each other. This wears away the surface of the rock

4. Chemical Weathering Answer: D
This occurs when chemicals break down rocks
Chemicals in groundwater break down underground rock and caves form
Acid rain breaks down stone or metal (like in statues)
Answer: D

5. What is erosion?
The process through which weathered rock is moved from one place to another
Land can be eroded by gravity, glaciers, running water, waves, or wind
Erosion is a DESTRUCTIVE PROCESS
Gravity
Rocks and soil on a slope can be loosened by the pull of gravity and eventually brought down the slope.
Mudslides occur when rain that can no longer soak into the ground mix with the soil and get pulled down by gravity
Landslides are the movement of a large amount of rock and soil down a slope

6. What is erosion?
Glaciers
A large mass of slowly flowing ice
Glaciers form in cold areas where snow piles up and freezes
As the glacier moves, it carries away weathered pieces of rock
The bits of rock wear away the ground at the beginning of the glacier, forming a steep bowl-shaped hollow called a cirque
A valley that had a sharp V-shape before a glacier came through will not have a U-shape, with a flatter bottom and sides

7. Answer= A
Glaciers are responsible for carving out U-shaped valleys

8. What is deposition
The process by which eroded materials are dropped off in another place
This is a CONSTRUCTIVE PROCESS
When a glacier erodes dirt and rock, the eroded materials are pushed in front of it. When the glacier starts to shrink, the eroded materials are left behind
Erosion and deposition can work together to change the shape of Earth’s surface

9. Erosion & Deposition by running water
As water flows down hills, it can wash away soil and erode rock. The water, soil, and rocks will eventually flow into a larger body of water, such as a river
Rivers with fast-moving water tend to follow straight paths and have deeper channels and steeper banks.
Rivers with slow-moving water tend to follow looping paths and have shallow channels and low banks
More deposition occurs in slow-moving rather than fast-moving water
Meanders, or gentle loops, sometimes form in rivers with slow moving water. Water moves slowly around the inside of a meander.
Particles of soil and rock that are carried along in water are called sediment.

10. Erosion & Deposition by running water
As sediment is being carried down stream it can be deposited into different areas and form other pieces of a land
A river delta is a landform that is formed at the mouth of a river, where the river flows into an ocean, sea, estuary, lake, or reservoir
The Mississippi River Delta has been formed by the Mississippi River

11. Erosion and Deposition by waves
Waves often hit beaches at an angle or curve as they move into shallower water
The shoreline is eroded by the waves because they move rocks and sand further down the beach or to the side
When waves wash sand off beaches, they may be deposited in the water rather than back on the beach
Sandbar is a strip of land that forms from deposited sand

12. SANDBAR

13. Erosion and deposition by wind
Wind can wear away rocks, smoothing them out.
Wind also can move sand or sediment from one place to another
When the winds slow down, the sand and soil are deposited

14. How are shorelines changed?
Running Water
Water runs over the ground into streams and rivers. Sometimes, water enters a river faster than a river can carry it away. When water collects on land that is normally dry, it is a flood
Flooding occurs when water from a body of water overflows banks or beaches
Floodplains are places that are easily flooded when river water rises
Natural wetlands can soak up water and reduce the chances of a flood.
Draining wetlands or cutting down plants along a riverbank may make floods more likely
Floods can erode the shoreline of a body of water and change its shape or course
Flooding can be a positive because the soil becomes rich in nutrients

15. How are shorelines changed?
Waves
When large sandbars stretch for hundreds of kilometers along a coastline, they are called barrier islands
Waves hit barrier islands first and erode the barrier islands rather than the coastline beaches
Wind
Some coastal areas have one or more sets of dunes running along the shoreline directly inland from the beach
A dune forms when wind erodes sand and deposits it along the back of the beach
Dunes form in the direction that the wind usually blows. They protect areas farther inland from the large waves that can occur during storms

16. How can shorelines be protected
A shoreline may be damaged when more sand is being eroded than deposited
People can protect river shorelines by changed the speed or direction of running water
Dams can control the speed of the flour of water in a river
Canals or channels can be dug to carry away water that would cause flooding
Fences and grasses help keep sand dunes from being eroded by wind