External Forces of Change Weathering & Erosion. 1. Explain the difference b/w weathering & erosion. Weathering breaks down rocks on Earth’s surface.

External Forces External Forces of Changeof Change

Weathering & ErosionWeathering & Erosion

1. Explain the difference b/w 1. Explain the difference b/w weathering & erosion.weathering & erosion.

Weathering breaks down rocks on Weathering breaks down rocks on Earth’s surface into smaller Earth’s surface into smaller piecespieces

Erosion wears away Earth’s Erosion wears away Earth’s surface (wind, glaciers, moving surface (wind, glaciers, moving water)water)

2. Explain the difference b/w 2. Explain the difference b/w physical & chemical physical & chemical weathering; give example.weathering; give example.

Physical- breaks rock into smaller Physical- breaks rock into smaller pieces pieces Water freezes in crack, ice splits Water freezes in crack, ice splits

rockrock

2. Explain the difference b/w 2. Explain the difference b/w physical & chemical physical & chemical weathering; give example.weathering; give example.

Chemical- changes the actual Chemical- changes the actual chemical make-up of the rockchemical make-up of the rock Water + CO2Water + CO2 destruction of destruction of

limestonelimestone

3. What causes acid rain?3. What causes acid rain?Acidic chemicals from pollution Acidic chemicals from pollution

(factories, etc) combine w/ (factories, etc) combine w/ precipitationprecipitation Eats away at buildings, kills Eats away at buildings, kills

fish/plants, etc.fish/plants, etc.

4. What is wind erosion?4. What is wind erosion?5. Benefits & drawbacks?5. Benefits & drawbacks?

Movement of dust, sand, soil from Movement of dust, sand, soil from one place to anotherone place to another Benefits: Mineral-rich soil is Benefits: Mineral-rich soil is

deposited creating fertile soildeposited creating fertile soil Drawbacks: Good soil can be Drawbacks: Good soil can be

carried away leaving land barrencarried away leaving land barren

6. Define LOESS.6. Define LOESS.

Fertile, yellow-gray soilFertile, yellow-gray soil carried carried by wind throughout the Yellow by wind throughout the Yellow River leaving the land great for River leaving the land great for farmingfarming

7. How can glaciers cause 7. How can glaciers cause erosion?erosion?

Slowly move Slowly move downhilldownhill p.u. p.u. soil/rockssoil/rocks destroy destroy forests, carve forests, carve valleys, alter river valleys, alter river course, wear down course, wear down mtns.mtns.

8. What are moraines?8. What are moraines?Large piles of debris/rocks left Large piles of debris/rocks left

behind by glaciersbehind by glaciers Form long ridges of land or create Form long ridges of land or create

dams that form glacial lakesdams that form glacial lakes

9. Describe the difference b/w 9. Describe the difference b/w sheet glaciers and mtn. sheet glaciers and mtn. glaciers.glaciers.

Sheet: flat, broad Sheet: flat, broad sheets of ice sheets of ice (Greenland, (Greenland, Antarctica)Antarctica) Can break Can break

off to form icebergsoff to form icebergs

Mtn: found in Mtn: found in high mts. high mts. (Rockies)(Rockies) Move Move

downhill downhill creating creating valleysvalleys

10. How does water cause 10. How does water cause erosion?erosion?

Fast-moving water Fast-moving water cuts into land, cuts into land, wears away wears away soil/rock soil/rock creates creates sediment which sediment which grinds away other grinds away other rocksrocks

Waves erode cliffs, Waves erode cliffs, beaches, etc.beaches, etc.