THE SHAPE OF THE EARTH’S SURFACE

Kayla WhiteheadMr. Fabel

7.11.5

WWK

The Students will understand that the shape of Earth’s surface is constantly changing due to effects of erosion and deposition.

Erosion

Erosion is the process of eroding or being eroded by wind, water, or other natural agents.

The five agents of erosion: wind, running water, glaciers, waves and gravity

Soil erosion occurs when soil is blown away by wind or washed away by rain

Wind erosion occurs in areas with little or no vegetation

Rainfall and runoff are the most important direct drivers of severe soil erosion by water

Slopes are also more susceptible to losing soil because of the combined effects of gravity and running water

Deposition

Deposition is the act of deposing. Creates land forms such as alluvial fans and deltas. It

can also add soil to a river’s flood plain.

When wind slows down is can drop sediment

Deposition happens in rivers when the water slows down and creates a new bank or delta

Abrasion

Abrasion is a carrying wave hits land, the sediment wears away rock like sandpaper

wearing away wood.

Crash against rocks causes erosion in three ways: Abrasion Hydraulics: water can’t be compressed-

forced crack rock Salt water dissolves rock

Deflation

Deflation is the process where wind erosion creates blowout depressions or deflation

hollows by removing and transporting sediment and soil.

Deflation creates a concentrated surface made of rock formally knew as “desert pavement”

Video

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KS

What are the five agents of erosion?

EARTH'S SUBSYSTEMS

Pamela JimenezPeriod: 7

E.S.S

WWK

Students will investigate the interdependence of Earth's subsystems and

the use of Earth's resources

Biosphere

The biosphere is made up all living organisms on Earth

All the life forms on earth alter and transform the system.

When carbon levels increase in the atmosphere, plants grow quicker.

As plants continue to grow, they get rid of more an more atmosphere from the air

Atmosphere

The atmosphere surrounds the earth and protects it from extraterrestrial debris and radiation

The atmosphere has different layers. One of the many is the ozone layer.

The ozone layer is found on the lower part of the stratosphere.

The atmosphere is made up of 5 layers. The layer that is closet to the earth is

called the troposphere and it the layer that includes the weather.

The layer above troposphere is 30-35 miles away from earth which is called the Stratosphere.

The air is really thin in the mesosphere which is between 35-50 miles away from the earth.

Temperature increases the higher the layer is, this layer is is between 50-400 miles away, it is called the thermosphere.

The outermost layer is the exosphere and it is 6200 miles away, and has very few molecules

Geosphere

The physical earth which includes rocks, magma and soil are all part of the geosphere.

The geosphere also includes the crust and the mantle on earth

Also known as the lithosphere

Hydrosphere

The hydrosphere includes all the water on earth.

Oceans, lakes, rivers, streams, etc. water makes up 75% of the earth Water hydrates the earth, and is used to

hydrate living organisms.

Vocabulary Overview

Ozone layer Troposhere Stratosphere Mesosphere Thermosphere Exosphere

Video

http://www.youtube.com/watch?v=J5ViCNJAkHg

Kick Starter

Which subsystem deals with the physical trait of the Earth?

The Forces that change the face of the Earth

Breyonna Vann4/8/13

Pd. 7

WWK

Students will understand how the shape of the earths surface is constantly changing due to the effects of Weathering, Erosion, and Deposition.

Overview of the Earth’s Surface

The Earths Surface is the outer most level of the land which 70% of it is covered with water and the remaining 30% is made up of the seven continental landmasses.

The surface of Earth is consisted of mountains, valleys, rivers, oceans, plains, fields, volcanoes, and lot's of other land masses

Underneath the water that fills the oceans, dirt, and plants, the Earth’s surface layer is made of rock.

Weathering

Weathering is the breaking up of surfaces by forces such as the air and water of the atmosphere. Weathering is also known as the preparation for erosion. It is a

fundamental Earth process that changes rocks from a hard state, to become much softer and weaker, making them more easily eroded. Weathering gradually

weakens rocks, and eventually produces new geological materials (rock fragments, sands, silts and clays) that are more stable in the new environment.

Two Types of Weathering

1) Mechanical Weathering is the breaking up of rocks by physical forces. In this natural process, physical forces split rocks apart but do not change their composition. Ice wedging, pressure release, plant root growth, and abrasion can all cause mechanical weathering.

Example-Ice Wedging Sometimes roads need constant repair because of weathering. In the

spring and fall, water may enter cracks in a road's surface and when this water freezes overnight, it expands and widens the cracks. This can break up huge boulders on the earths surface.

Two Types of Weathering (Cont.)

2) Chemical Weathering is the breakdown of rocks by chemical reactions that change the rocks composition. Sometimes, chemical weathering dissolves large regions of limestone or other rock on the surface of the Earth to form a landscape called karst. In these dramatic areas, the surface rock is marked with holes, sinkholes, and caves. Water is the main cause of chemical weathering. Example-Caves Sometimes, carbon dioxide from the air/soil combines with water which

can produce a weak acid, called Carbonic Acid, that can dissolve rock and limestone. When the carbonic acid seeps through limestone underground, it can open up huge cracks or hollow out vast networks of caves. Carlsbad Caverns National Park, in New Mexico, has more than 110 limestone caves.

Erosion affecting the Earth’s Surface

Erosion is a natural process which is made by rock and soil being released from the earth's surface which is moved from one location to another. Erosion changes the landscape by wearing down mountains, filling in valleys, and making rivers appear and disappear. It is usually a gradual process that occurs over thousands or millions of years, but erosion can be speeded up by human activities such as farming and mining. Erosion begins with the process called weathering.

Example-Canyon Erosion is believed to be one of the main causes of

the formation of the Grand Canyon, in Arizona. The reason why is due to the soil content, as well as the fact that the Grand Canyon is mostly made up of desert. Sands that make up the ground in the canyon are very brittle after being baked by the sun, thus making them susceptible to substantial erosion.

Deposition affecting the Earth’s Surface

Deposition is when sediment such as small rocks, are deposited into different areas. This is also known as the process that follows erosion.

Erosion can be a very destructive force, but together with deposition, it can also be a force of creation. These two processes are responsible for the creation of new landscapes, including hills, valleys and coastlines. Though erosion can alter an area, the affected parts are not destroyed but simply moved. Deposition allows these parts to settle elsewhere.

Various changes in the surrounding environment can aid in the process of deposition. Trees and plants can slow the flow of water or divert the force of wind, which can allow the process to begin. Similarly, hills, buildings, large rocks and other obstacles can halt or slow a flowing agent enough for sediment to fall out and settle.

Video Link: http://www.youtube.com/watch?v=E-cqEruUgBU

K.S.

What is the main cause of Chemical Weathering?