What’s Wrong With This Picture?What’s Wrong With This Picture?

Take a minute to write down a list of what you think is wrong with these statues!

Changes in the Earth’s Changes in the Earth’s SurfaceSurface

Chapter 1.3Chapter 1.3

Weathering & ErosionWeathering & Erosion

((Forces that change the Earth Forces that change the Earth over a period of timeover a period of time….)….)

WeatheringWeathering

Weathering: Breakdown of rock at or Weathering: Breakdown of rock at or near the earth’s surface into smaller near the earth’s surface into smaller pieces. pieces.

*2 Kinds of Weathering: *2 Kinds of Weathering:

*Mechanical Weathering *Mechanical Weathering

*Chemical Weathering *Chemical Weathering

Mechanical WeatheringMechanical Weathering Rock is broken/weakened Rock is broken/weakened

physicallyphysically

Frost Wedging: water freezes Frost Wedging: water freezes to ice in cracked rock, the ice to ice in cracked rock, the ice expands and creates a bigger expands and creates a bigger crack. crack.

Seeds taking root in cracked Seeds taking root in cracked rock. rock.

Over time these types of Over time these types of weathering can cause huge weathering can cause huge parts of mountainside to break parts of mountainside to break and fall away!!and fall away!!

Chemical WeatheringChemical Weathering

Mechanical weathering changes the Mechanical weathering changes the structure of a rock, CHEMICAL structure of a rock, CHEMICAL weathering alters the rock’s chemical weathering alters the rock’s chemical makeup makeup

Can change one kind of rock into Can change one kind of rock into anotheranother

Water and Carbon Dioxide (air, soil)-Water and Carbon Dioxide (air, soil)-when mixed =Carbonic acidwhen mixed =Carbonic acid

Chemical ChangeChemical Change

The acidic water seeps into The acidic water seeps into cracks (i.e.Limestone) and cracks (i.e.Limestone) and dissolves rock. dissolves rock.

Acid Rain: Chemicals in the Acid Rain: Chemicals in the polluted air combine with polluted air combine with water vapor and fall as acid water vapor and fall as acid rain. rain.

Acid rain destroys forests, Acid rain destroys forests, pollutes water, & eats away at pollutes water, & eats away at the surfaces of buildings the surfaces of buildings

Limestone CavesLimestone Caves

ErosionErosion

Movement of weathered Movement of weathered materials such as gravel, soil, materials such as gravel, soil, and sand.and sand.

3 Common Causes of Erosion: 3 Common Causes of Erosion:

*Water*Water

*Wind*Wind

*Glaciers*Glaciers

WaterWater Largest canyons/deepest valleys created in part Largest canyons/deepest valleys created in part

by moving water (rain, rivers, streams, by moving water (rain, rivers, streams, oceansoceans)) Water = Greatest cause of erosion. Water = Greatest cause of erosion.

Water carries sediment (small particles of Water carries sediment (small particles of soil/sand/gravel) which helps grind away soil/sand/gravel) which helps grind away surface rocks in the water’s path!surface rocks in the water’s path!

Sediment is eventually deposited (i.e. Sediment is eventually deposited (i.e. Mississippi River carries 159 million tons of Mississippi River carries 159 million tons of sediment per year!) sediment per year!)

Water Erosion-Devastating EffectsWater Erosion-Devastating Effects

FLOODING: Can occur when:FLOODING: Can occur when: heavy, intense rainfall heavy, intense rainfall run-off from a deep snow run-off from a deep snow

cover cover over-saturated soil, when over-saturated soil, when

the ground can't hold the ground can't hold anymore water. anymore water.

*Flooding causes erosion of *Flooding causes erosion of the land and other physical the land and other physical characteristics. characteristics.

*Flooding also destroys *Flooding also destroys private/public property and private/public property and endangers lives. endangers lives.

New OrleansNew Orleans

Wave Action = ErosionWave Action = Erosion

Historic New England FloodsHistoric New England Floods

http://www.pbs.org/wgbh/amex/hurricane38/sfeature/sfhttp://www.pbs.org/wgbh/amex/hurricane38/sfeature/sf_footage.html_footage.html (Video Clip) (Video Clip)

Houses were built on shifting sand, too close to the sea. Houses were built on shifting sand, too close to the sea. Bridges were too flimsy, roads too low. When the Bridges were too flimsy, roads too low. When the September hurricane struck it brought massive September hurricane struck it brought massive flooding, one resident said, "It was your worst flooding, one resident said, "It was your worst nightmare coming true.“nightmare coming true.“

In the storm's aftermath, city streets became surreal In the storm's aftermath, city streets became surreal junkyards full of debris, traveled by looters in rowboats. junkyards full of debris, traveled by looters in rowboats. Entire beach communities disappeared. Thousands of Entire beach communities disappeared. Thousands of livestock were killed. New England lost 275 million livestock were killed. New England lost 275 million trees, including a third of Vermont's sugar maples. And trees, including a third of Vermont's sugar maples. And hundreds of people died.hundreds of people died.

WINDWIND

22ndnd Major Cause of Major Cause of Erosion (esp. in areas Erosion (esp. in areas with little water). with little water).

LoessLoess SandstormsSandstorms Dust Bowl 1930’sDust Bowl 1930’s

(Video Clip) (Video Clip) http://www.livinghistoryfahttp://www.livinghistoryfarm.org/farminginthe30s/rm.org/farminginthe30s/water_02.html water_02.html

GlaciersGlaciers

Glaciers: Huge, slow-moving sheets Glaciers: Huge, slow-moving sheets of ice (form over years of unmelted of ice (form over years of unmelted snow pressed together, thaw slightly, snow pressed together, thaw slightly, and then turn to ice)and then turn to ice)

When glaciers move they carry dirt, When glaciers move they carry dirt, rocks, and boulders. The glacier rocks, and boulders. The glacier wears away the terrain in its path. wears away the terrain in its path.

Glaciers: The ImpactGlaciers: The Impact

Glaciers move (slide forward) due to Glaciers move (slide forward) due to their great weighttheir great weight carve U-shaped carve U-shaped

Basins of the Great LakesBasins of the Great Lakes Moraines: ridge-like piles of rocks Moraines: ridge-like piles of rocks

and debris left behind melted and debris left behind melted glaciers. glaciers.

Long ridges of land (Long Island) Long ridges of land (Long Island)

IcebergsIcebergs