Weathering & Erosion
Essential Question
How does weathering change Earth’s surface?
Weathering is the process of breaking down rock material by physical and chemical means.
1.Physical weathering is caused by temperature changes, pressure changes, plants and animals, water, wind, and gravity.
A. Temperature Changes-A rise in temperature will cause a rock to expand. A decrease in temperature will cause rock to contract.
-Desert Regions
-Ice Wedging
B. Pressure Changes-Rocks formed under pressure deep withing Earth can become exposed at the surface. As a result rock expands, causing it to be exposed to weathering.
C. Plants and Animals-Roots of plants can grow into the cracks of rocks causing them to break apart. Many animals dig burrows into the ground, allowing more rock to be exposed to weathering.
D. Water, Wind, and Gravity
Abrasions are the breaking down of rock material by the mechanical action (rubbing/exfoliation)of other rocks.
2.Chemical weathering breaks down rock by chemical reactions and is caused by acids and oxidation.
A. Reactions with Oxygen-Reactions cause rock to be affected by oxidation(rust) and cause a color change.
B. Reactions with Acid Precipitation-Rain is slightly acidic as it combines with gases, and fossil fuels.
C. Reactions with Ground Water-Water in the ground can cause cave formations and/or sinkholes.
D. Reactions with Living Things- Algae(lichen/moss) can cause chemical weathering of rocks overtime. These living organisms produce acidic, which can weaken rocks over time.
CHEMICAL REACTIONS WITH OXYGEN -(OXIDATION) RUST
Acid Rain
GROUND WATER CAN CAUSE ENORMOUS CAVE SYSTEMS
CHEMICAL REACTIONS WITH LIVING THINGS:LICHEN (MOSS) RELEASES ACID ON ROCKS WHICH CAUSES A FORM OF CHEMICAL WEATHERING
EROSION
Objective
-Model ways erosion and deposition can change the Earth's surface.
-Create a model that shows how water is a force that constantly changes the Earth's surface.
-Create a model that shows how strong winds cause reshaping of the Earth’s surface.
-Create a model that shows how gravity causes materials to move downhill either slowly or rapidly.
-Create a model that shows how glaciers can reshape the land.
What is Erosion?
In earth science, erosion is the action of surface processes (such as water flow or wind) that remove soil, rock, or dissolved material from one location on the Earth's crust, then transport it away to another location.
- EROSION AND DEPOSITION BY WATER
WAVES AND CURRENTS VS. BEACHES
DEPOSIT(DEPOSITION) SEDIMENT ON BEACHES
ERODE (EROSION) BEACHES
CHANNELS=RIVERS
ALL RIVERS LEAD TO OCEANS
FORMATION OF THE MISSISSIPPI DELTA
1.ALL RIVERS CARRY ERODED SEDIMENT SEDIMENT(WEATHERED ROCK) RIVERS ARE ON A GRADIENT AND CARRY A LOAD OF SEDIMENT. THIS LOAD OF SEDIMENT, DISCHARGES OUT OF THE DELTA. SOME SEDIMENT CAN DEPOSIT AND CAN CREATE AN ALLUVIAL FAN OR SMALL SEDIMENT ISLAND NEAR THE DELTA
