Weathering and Weathering and ErosionErosion

Objective: Investigate how Objective: Investigate how weathering and erosion weathering and erosion

changes the Earth.changes the Earth.

Have you ever had a mound of Have you ever had a mound of dirt in your yard?dirt in your yard?

What happens overtime?What happens overtime?

WeatheringWeathering Weathering is the Weathering is the SLOWSLOW wearing away wearing away

of rock into smaller pieces or sediment.of rock into smaller pieces or sediment.

Sediment is rock fragments and Sediment is rock fragments and particles that come from the particles that come from the weathering of rock and are carried and weathering of rock and are carried and deposited by wind, water, or ice. deposited by wind, water, or ice.

There are two types of weathering:There are two types of weathering:– Mechanical weatheringMechanical weathering– Chemical weatheringChemical weathering

Mechanical WeatheringMechanical Weathering

Mechanical weathering takes place Mechanical weathering takes place when rocks are broken down without when rocks are broken down without any change in the chemical nature of any change in the chemical nature of the rocks. the rocks.

The rocks are essentially torn apart The rocks are essentially torn apart by physical force, rather than by by physical force, rather than by chemical breakdown. chemical breakdown.

Mechanical WeatheringMechanical Weathering

Water- rivers, ocean, rain, freezing Water- rivers, ocean, rain, freezing and thawingand thawing

Heat- wildfires, extreme heatHeat- wildfires, extreme heat

Plants- trees, roots, vinesPlants- trees, roots, vines

Chemical WeatheringChemical Weathering

Chemical reactions break down the bonds Chemical reactions break down the bonds holding the rocks together, causing them to holding the rocks together, causing them to fall apart, forming smaller and smaller fall apart, forming smaller and smaller pieces. pieces.

Chemical weathering is much more Chemical weathering is much more common in locations where there is a lot of common in locations where there is a lot of water, because water is important to many water, because water is important to many of the chemical reactions that can take of the chemical reactions that can take place. place.

Example; the creation of clayExample; the creation of clay

Oxidation: Rocks can rustOxidation: Rocks can rust

Effects of Acid RainEffects of Acid Rain

ErosionErosion Erosion is the movement of rock Erosion is the movement of rock

material from ONE PLACE to material from ONE PLACE to ANOTHER.ANOTHER.

Materials that are the result of Materials that are the result of weathering are carried away by weathering are carried away by erosion.erosion.

Three main causes of erosion:Three main causes of erosion:Water, wind, and glaciersWater, wind, and glaciers

Erosion: WaterErosion: Water

Think of a drop of water that Think of a drop of water that splashes on the soil.splashes on the soil.

The water picks up tiny particles The water picks up tiny particles and moves them downhill.and moves them downhill.

As the water continues, As the water continues,

it picks up more particles it picks up more particles

and moves them too.and moves them too.

Erosion WindErosion Wind

Why are plants important for the Why are plants important for the protection from erosion?protection from erosion?

There are some areas of the world There are some areas of the world that do not have plants to hold down that do not have plants to hold down soil.soil.

When the wind blows, When the wind blows, it carries away sand it carries away sand and soil. and soil.

Erosion: GlaciersErosion: Glaciers

Glaciers are larges masses of slow- Glaciers are larges masses of slow- moving ice.moving ice.

It move so slowly that we can not see It move so slowly that we can not see it move.it move.

As it moves, a glacier can dig out As it moves, a glacier can dig out huge areas of rock to form deep huge areas of rock to form deep valleys and canyons.valleys and canyons.

DepositionDeposition

Deposition is the dropping of Deposition is the dropping of sediment moved by water, wind, and sediment moved by water, wind, and ice.ice.

DiscussionDiscussion

You have two rocks, one rough and You have two rocks, one rough and one smooth. Which has been one smooth. Which has been weathered more?weathered more?

Where would you observe Where would you observe weathering?weathering?

Where would you observe erosion?Where would you observe erosion?