Shaping the EarthShaping the Earth

External ForcesExternal Forces

Changing the Look of the EarthChanging the Look of the Earth

Weathering: physical and chemical Weathering: physical and chemical processes that change the rocks on the processes that change the rocks on the Earth.Earth.

2 Types:2 Types: Mechanical WeatheringMechanical Weathering Chemical WeatheringChemical Weathering

Mechanical WeatheringMechanical Weathering

Just think of parts of an Just think of parts of an engine…..engine…..

There are many parts that There are many parts that make up the whole make up the whole engineengine

Now think of a Rock Now think of a Rock breaking into smaller breaking into smaller piecespieces

Frost, water, human Frost, water, human activity, plants roots, etc activity, plants roots, etc can break up rocks into can break up rocks into smaller piecessmaller pieces

Chemical WeatheringChemical Weathering Look at the picture of the Look at the picture of the

Statue of Liberty NOWStatue of Liberty NOW Check out Lady Liberty Check out Lady Liberty

back in the day…back in the day… The Statue of Liberty The Statue of Liberty

turned green due to turned green due to chemical weathering.chemical weathering.

Chemical Weathering Chemical Weathering occurs when a rock occurs when a rock changes into something changes into something completely new due to air completely new due to air and water elements and water elements interacting with the rock. interacting with the rock.

ErosionErosion

Erosion: when weathered materials are Erosion: when weathered materials are moved by the action of wind, water, ice, or moved by the action of wind, water, ice, or gravitygravity

3 Types: 3 Types:

1. Water Erosion1. Water Erosion

2. Wind Erosion2. Wind Erosion

3. Glacial Erosion3. Glacial Erosion

Water ErosionWater Erosion

When rocks travel When rocks travel downstream by a riverdownstream by a river

Abrasion: the grinding Abrasion: the grinding away of rock by bigger away of rock by bigger rocksrocks

Delta: when rocks are Delta: when rocks are finally deposited finally deposited (dumped) out by a river(dumped) out by a river- Fan like form- Fan like form

Waves along the coast Waves along the coast can make beaches can make beaches expand or shrinkexpand or shrink

Nile River Delta

Wind ErosionWind Erosion

Wind picks up rocks Wind picks up rocks and deposits them in and deposits them in other locationsother locations

Examples: Dust Examples: Dust StormsStorms

Loess: wind blown silt Loess: wind blown silt and clay that make up and clay that make up fertile soil fertile soil

Glacial ErosionGlacial Erosion

Glaciers are huge blocks Glaciers are huge blocks of ice that are moved by of ice that are moved by gravity.gravity.

Glaciations occurs when Glaciations occurs when glaciers move over a glaciers move over a landformlandform

Moraine are the rock Moraine are the rock formations that are left by formations that are left by the glacier. Usually found the glacier. Usually found on the sides or the edges on the sides or the edges of the glacier.of the glacier.