External forces

Explain the difference b/w weathering and erosion

-Weathering breaks down rocks on Earth’s surface into smaller pieces

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

-Deposits sediment elsewhere

Weathering

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

Physical- breaks the rock into smaller pieces

-Ex: Water freezes in the crack, ice splits the rock, Broken tombstone

Chemical- changes the actual chemical make-up of the rock

-Ex: Water + CO2 destruction of limestone; Mammoth Cave (carbonic acid)

What causes acid rain?

Acidic chemicals from pollution (factories, etc.) combine w/ precipitation.

Eats away at buildings, kills fish/plants, etc.

-Ex: Bronze turning green when exposed to elements

Wind Erosion

What is wind erosion?

Movement of dust, sand, and soil from one place to another

-Ex: Bryce Canyon (with a little water erosion)

Benefits & drawbacks?

Benefits: Mineral-rich soil is deposited, creating fertile soil

Drawbacks: Good soil can be carried away, leaving the land barren

-Ex: Loess- Fertile, yellow-gray soil carried by wind throughout the Yellow River, leaving the land great for farming

Glacial Erosion

How can glaciers cause erosion?

Slowly move downhill while pulling soil and rocks, destroy forests, carve valleys, alter river course, wear down mtns.

-Ex: Glacier National Park, Grand Tetons

What are moraines?

Large piles of debris/rocks left behind by glaciers

Form long ridges of land or create dams that form glacial lakes.

-Ex: Great Lakes

Describe the difference b/w sheet glaciers and mtns. glaciers.

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

-Can break off to form icebergs

Mtn: found in high mtns. (Rockies)

-Move downhill, creating valleys

Water Erosion

Fast-moving water →cuts into land and wears away soil/rock → creates sediment which grinds away other rocks.

Waves erode cliffs, beaches, etc.

-Ex: Grand Canyon and Colorado River