unit 4 weather, erosion & deposition. this unit you will learn 1.what is and what are the...

Unit 4 Weather, Erosion & Deposition

This unit you will learn1. What is and what are the factors of weathering.2. What is and what are the factors of erosion.3. What is and what are the factors of deposition.4. The difference between soil and dirt! Yes there is

one.5. Types of weathering, erosion & deposition.6. Mass movements7. Glaciers8. Rivers9. Landscape regions

Much of this unit is review?!• So, let’s try to use this unit to get your grade

up before the last few units of the year.

Definitions for the day

• Weathering– Chemical weathering– Physical weathering

• Surface area• Abrasion• Frost action• Root Pry• Oxidation

Weathering

• Weathering- The breakdown of material.• Erosion- The movement of material that has

been weathered.• Deposition- The leaving behind of weathered

material.

How can we change weathering rates?

• Surface area- the amount of area available to be weathered.

• If we increase the surface area what will happen to the amount of potential weathered area?

Let’s try?!• SA=L x W x # of sides– L-Length– W-Width

• 4 cm * 4 cm * 6 sides • SA= 96 sq cm

4 cm

4 cm

4 cm

You try

• Formula:?• Substitute #’s• SA=???

• SA=2 * 2 * 6 • SA= 24 sq cm

2 cm

2 cm

2 cm

Now what?

• What if we cut the cube in half?

• OLD SA= 24 sq cm

• NEW SA= ???– SA= 1 * 1 * 48 sides– SA= 48 sq cm

• INCREASE SA = Decrease in size!!

2 cm

2 cm

2 cm

1 cm 1 cm

1 cm

Types of weathering• Chemical– Changing the

chemical make up of a substance• Oxidation• Hydration• Carbonation

• Physical– Changing the shape

appearance or texture without changing chemical properties• Abrasion• Exfoliation• Frost Wedgies

Take note

• Chemical – End does not equal the same thing as the beginning!

• Physical- End same as beginning!

So, if something has undergone physical weathering then the ending object is the same chemically as the beginning. If an object has been chemically weathered then the end object is different from the beginning object.

You try!

• A rock hitting another rock? C or P• A pot hole? C or P• A rock with a red coloring? C or P• A bonfire? C or P• A tree with roots in the bed rock? C or P• Hitting a hammer on a rock? C or P• Putting a tooth in a cup of Pepsi? C or P

P

P

P

P

CC

C

Factors

1. Exposure

2. Particle Size

3. Composition

4. Climate

Exposure• Exposure to:– Wind– Rain, Sleet, Snow– Biologic activity

• How does this affect weathering

Particle Size

• Surface area– More surface area = more weathering

• A large boulder the size of a house has a small amount of surface area.

• A pile of small sand grains = the size of a boulder will have more surface area.

Particle Size

• Surface area– More surface area = more weathering

• A large boulder the size of a house has a small amount of surface area.

• A pile of small sand grains = the size of a boulder will have more surface area.

Climate

• What is the climate of a rainforest?– Wet small temperature range

• What about the desert?– Dry large temperature range

• Ice can only form when its cold while constant water will smooth out particles.