How do weathering

and erosion shape the

land?

UNIT C:

CHAPTER 5: LESSON 5:

Weathering

The process in which rocks or other materials are broken down.

Different types of weathering:

Physical weathering Chemical weathering

Physical Weathering:

Physical weathering is caused by:

1) Temperature changes

(Causes rocks to crack)

2) Plant roots growing in rocks breaking the rocks.

3) Water freezing in cracks between rocks cause the

rocks to break apart.

4) Rubbing

5) Animals making burrows.

Chemical Weathering:

Occurs when chemicals break down the rocks.

1) Water dissolves rocks.

The agents of chemical weathering:

2) Acid Rain

Formed when gases from factories combine with rain water.

Erosion

The process by which water, ice, wind or gravity moves

fragments of rock and soil.

If a particle is loosened by

weathering, but stays put, its

just weathering.

If it starts moving, its Erosion.

Water Erosion

Rivers, streams, and runoff

Ice Erosion

Glaciers

Wind Erosion

Mass Movements

Landslides, mudslides, slump and creep

Get out a piece of paper and identify if the following involve

weathering, erosion, both, or neither.

Ready?

1.Waves are crashing on a sand beach.

2.Water expands as it freezes in the cracks of rocks.

3. Pebbles move down a stream with the current.

4. Acid rain causes the decomposition of a statue in New York.

5. A man shovels dirt to plant a tree.

6. A Glacier slowly moves down a mountain.

7. A tree’s roots grow into the cracks of rocks.

8. A major volcano erupts.

9. A boy takes out the

garbage for his mother.

10. A shovel is left outside

and begins to rust.

Once you’ve answered these,

discuss you’re answers with the

rest of the class before you go

on.

Let’s Discuss The Questions.

1. As the sand is moving there is

definitely erosion; there is also

abrasion from the sand gains

colliding. Both

2. This is frost wedging so it’s

mechanical weathering.

There is no mention of

movement. Weathering

3. There is probably some

weathering, but there is

definitely erosion. Erosion or

Both

4. Acid rain on a statue is

chemical weathering. This is

mainly Weathering.

5. Since the man is

transporting Earth materials,

it’s Erosion.

6. A glacier moving down a

mountain would have both

weathering and erosion.

Both

7. A tree’s roots growing into

cracks of rocks would be

weathering. Weathering

8. A major volcanic eruption

would involve both

weathering and erosion.

Both

9. Unless the garbage has

“Earth Material” or dirt in it

there is probably no erosion

or weathering. Neither

10. The rusting of a shovel is

oxidation. This is chemical

weathering. Weathering

The process by which materials are

dropped off at another place is called:

Deposition

Erosion and

deposition work

together to change

the shape of the

earth’s surface.

Ways that erosion and deposition work together:

1) Running water

Slow moving water Deposition

Fast moving water Erosion

2) Waves

Headland

Land surrounded by

water from 3 sides.

When waves reach a headland they

curve around it and wash away at

the sides of the headland.

3) Wind

Wind erodes sand and rock, when the

wind slows down the sand and rock get

deposited.

How can people protect shorelines?

Shorelines may be damaged when more sand is

eroded than deposited.

People can protect shorelines by:

1) Building dams (to change the speed and direction

of water)

2) Building levees (prevent floods)

3) Building barricades (prevent beach erosion)

4) Building fences (prevent sand erosion by wind)