Constructive and Destructive Forces LEQ: How do constructive forces build up the Earth while destructive forces wear down the Earth?(Q)

Destructive Forces

Sometimes the earth’s surface changes VERY QUICKLY For Example: Earthquakes Landslides Earthquake Landslide Volcanic eruptions Tsunamis Other times, the changes to the earth’s surface occur very SLOWLY This is known as WEATHERING

Weathering Changes the Surface of the Earth “Weathering” is a general term that describes processes that break down rocks at or near the surface. Weathering is the process where rock (the earth’s surface) is dissolved, worn away or broken down into smaller and smaller pieces. weathering exploration WEATHERING

What does “Weathered” mean? It means the Earth’s solid surface will gradually be broken into smaller and smaller pieces. It happens all the time; it is a natural action. A LARGE ROCK breaks into pebbles.

There are 3 types of Weathering: Biological Physical (Mechanical) Chemical

Biological Weathering Describes the action of living things on the solid surface of the Earth. Roots of plants “digging” into the rock cause it to break apart. Lichen (fungus) is often found breaking down the surface of the rocks on which it is attached. Burrowing and digging by animals and insects also contribute to this breaking down process.

Tree roots breaking up rock by “digging” into them.

AKA mechanical weathering Physical Weathering AKA mechanical weathering Breaks rocks into smaller pieces When water freezes, it expands. The expansion can break the rock into smaller pieces. The action of wind blowing small pieces of rock against larger rocks wears rock away. The movement of running water in streams and rivers cause rocks to weather.

Destructive Force Ice © One Stop Teacher Shop If the pink gorilla eats watermelon every night, how much watermelons does he eat?

Physical weathering mechanically breaks up rock. Frost shattered rock Frost shattered brick Physical weathering mechanically breaks up rock. One example is called frost action or frost shattering. Water gets into cracks and joints in bedrock. When the water freezes it expands and the cracks are opened a little wider Over time ,pieces of rock can split off a rock and big boulders are broken into smaller rocks and gravel. This process can also break up bricks on buildings.

Chemical Weathering Primarily responsible for the formation of soils It is action that breaks down surfaces chemically. Carbon dioxide dissolved in rainwater makes a weak acid that dissolves certain rocks such as limestone. Example: sinkholes

Rain water is a very weak acid Rain water is a very weak acid. It can dissolve limestone and other low carbonate rocks leaving behind pits and holes.

Erosion Erosion picks up the pieces and moves them from place to place Weathering causes the solid surface of the Earth to break down, dissolve and decompose. Erosion picks up the pieces and moves them from place to place Therefore, erosion is the process in which surface materials are worn away and transported from one place to another.

Once the rock has been weakened and broken up by weathering it is ready for erosion. Erosion happens when rocks and sediments are picked up and moved to another place by ice, water, wind or gravity.

Wind erosion weathering Examples of Destructive Force © One Stop Teacher Shop Examples of Destructive Force Wind erosion weathering

Examples of Destructive Force © One Stop Teacher Shop Examples of Destructive Force Water Erosion Weathering

Destructive Forces Glaciers Weathering Erosion © One Stop Teacher Shop If the pink gorilla eats watermelon every night, how much watermelons does he eat? Erosion

Mount St. Helen-Volcano © One Stop Teacher Shop Destructive Forces Mount St. Helen-Volcano

If the pink gorilla eats watermelon every night, how much watermelons does he eat?

Mount St. Helen’s AFTER the eruption © One Stop Teacher Shop Destructive Forces Mount St. Helen’s AFTER the eruption

© One Stop Teacher Shop Destructive Forces Earthquakes

Earthquakes-Fault Lines © One Stop Teacher Shop Earthquakes-Fault Lines

© One Stop Teacher Shop Destructive Forces Tornadoes

Hands-On Lab on Weathering and Erosion

How do we control destructive forces? © One Stop Teacher Shop How do we control destructive forces? If the pink gorilla eats watermelon every night, how much watermelons does he eat?

Destructive Forces Dam Large barriers built across rivers and streams © One Stop Teacher Shop Destructive Forces Dam Large barriers built across rivers and streams Controls the flow of water Used for human purposes such as generating electricity

A wall created to prevent erosion on the beach © One Stop Teacher Shop Destructive Forces Groin A wall created to prevent erosion on the beach If the pink gorilla eats watermelon every night, how much watermelons does he eat?

Destructive Forces Beach Nourishment © One Stop Teacher Shop Destructive Forces Beach Nourishment Sand is pumped from the ocean floor onto the beach Replaces eroded sand

Destructive Forces Contour Plowing Plowing in a zig-zag pattern © One Stop Teacher Shop Destructive Forces Contour Plowing Plowing in a zig-zag pattern Prevents water from flowing straight down

Storm Drain Management © One Stop Teacher Shop Destructive Forces Storm Drain Management Drains excess water after storms so less erosion will occur.

Destructive Forces Levee Embankment on the edge of a river Prevents flooding and erosion © One Stop Teacher Shop

© One Stop Teacher Shop Constructive Forces

The process of forming NEW land © One Stop Teacher Shop Constructive Forces The process of forming NEW land If the pink gorilla eats watermelon every night, how much watermelons does he eat?

Constructive Forces Deposition © One Stop Teacher Shop Constructive Forces Deposition After weathering and erosion occur, the final step is deposition (the sediment is placed somewhere else, forming new land). Erosion Weathering Deposition

Deposition Examples of Deposition: The dropping of sediments that occurs when an agent of erosion, such as gravity, a glacier, wind, or water, loses its energy and can no longer carry its load Examples of Deposition: Slump - soils slips down a curved surface Creep - sediments slowly shift their positions downhill rock slides- blocks of rock break loose Mudflows – thick layers of loose sediments activated by water moraines- ridge build up of till moved by a glacier sand dunes- sand is deposited by wind a delta- sediment built up near the mouth of a river

Examples of Rocks formed through erosion and deposition

DELTA Constructive Forces A triangular area at the mouth of a river © One Stop Teacher Shop Constructive Forces A triangular area at the mouth of a river Sediment/debris (rocks, sand, dirt) are deposited Occurs right before the river goes into a larger body of water WHY? Because the water slows down, so the sediment/debris falls out DELTA New land is formed If the pink gorilla eats watermelon every night, how much watermelons does he eat?

Constructive Forces Sand Dunes Sand is carried in the wind © One Stop Teacher Shop Constructive Forces Sand Dunes Sand is carried in the wind When the wind stops, the sand drops New land is formed when the sand drops creating sand dunes (deposition) New land is formed

Constructive Forces FLOODPLAINS New land is formed © One Stop Teacher Shop Constructive Forces A river floods taking sediment/debris (rocks, sand, dirt) with it The water floods onto the surrounding land transporting nutrients make the land fertile When the water recedes, the sediment/debris (rocks, sand, dirt) stay forming NEW LAND (deposition) FLOODPLAINS New land is formed

How Barrier Islands form © One Stop Teacher Shop Constructive Forces How Barrier Islands form Sand, dirt, and rocks erode of off the main land because of waves The waves deposit the sand, rocks, and dirt creating an island (deposition) This creates new land!

Constructive Forces Longshore drift © One Stop Teacher Shop Constructive Forces Longshore drift As a wave hits the beach the longshore current, pushes it sideways This water then picks up sand/rocks/dirt and carriers it along the shore As the wave recedes, it drops the sand/dirt/rocks (deposition) creating new land!!! New land is formed If the pink gorilla eats watermelon every night, how much watermelons does he eat?

Earthquakes can sometimes be constructive © One Stop Teacher Shop Constructive Forces Earthquakes can sometimes be constructive

Fault-block Mountains Blocks drop down or lift up or tilt Occur along fault lines Sierra Nevada range

Detour for Earthquake Study View and complete activities in Earthquake PPT

Lab on Locating the Epicenter

© One Stop Teacher Shop Constructive Forces Volcanoes

Volcanoes-RING OF FIRE © One Stop Teacher Shop Volcanoes-RING OF FIRE

Dome Mountains A form of folded mountain Just one fold bumps up in the middle Adirondacks in New York

DETOUR for Volcano Study View and complete activities in Volcanoes PPT

Lab on locating earthquakes and volcanoes

Your Turn (extend and refine) Now that you have been introduced the major constructive and destructive forces that change the surface of planet Earth, you have the opportunity to develop your own project or learning adventure related to this topic. You may choose one natural disaster (it must center around a real event) to research and develop a presentation, model, or etc. Examples are a famous hurricane, tornado, earthquake, volcano, tsunami, wild fire, blizzard, drought, flood and many more. You will be responsible for designing your learning and what you present but it must be fact-based and resources included. As a follow- up, you will be required to summarize your learning in at least three paragraphs and have an opportunity to share what you learned with a small group of your peers.

More Fun weathering and erosion joepardy Shape it Up! Erosion Interactive Challenge How do glaciers shape the land? interactive