External forces that shape our planet
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External Forces That Shape Our Planet. Presentation created by Robert L. Martinez Primary Content Source: World Geography by McDougal Littell Images as cited. http://www.uvm.edu/~inquiryb/webquest/fa08/jlfisher/worksheets.html. http://www.ers.usda.gov/Briefing/AgAndEnvironment/background.htm.

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External Forces That Shape Our Planet

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External forces that shape our planet

External Forces That ShapeOur Planet

Presentation created by Robert L. Martinez

Primary Content Source: World Geography by McDougal Littell

Images as cited.

http://www.uvm.edu/~inquiryb/webquest/fa08/jlfisher/worksheets.html

http://www.ers.usda.gov/Briefing/AgAndEnvironment/background.htm


External forces that shape our planet

Weathering refers to physical and chemical processes that change the characteristics of rock on or near the earth’s surface.

www.csulb.edu


Weathering occurs slowly over many years and even centuries

Weathering occurs slowly over many years and even centuries.

http://www.ask.com/wiki/Wind_erosion


External forces that shape our planet

Weathering processes create smaller and smaller pieces of rock called sediment. Sediment is mostly identifiable as either mud, sand, or silt, which is very fine particles of rock.

http://www.pubinfo.vcu.edu/masc/photos-2003-04/photos-2003.htm

kohalacenter.org


Processes that break rock into smaller pieces are referred to as mechanical weathering

Processes that break rock into smaller pieces are referred to as mechanical weathering.

skywalker.cochise.edu/wellerr/students/green-sand/project.htm


External forces that shape our planet

Mechanical weathering does not change the composition of the rock, only its size and shape. For example, when ice crystals build up in the crack of a rock, they can actually create enough pressure to fracture the rock into smaller pieces.

http://kayty.glogster.com/glog-8007/


External forces that shape our planet

All sorts of agents can break apart rocks. Frost and even plant roots dig into crevices in the rock, splitting it.

http:[email protected]/4173374526/


External forces that shape our planet

Human activities like road construction or drilling and blasting in mining, are also mechanical weathering forces.

http://gpssystems.net/tag/chilean-mine-disaster/


Eventually the smaller broken material will be combined with organic material to become soil

Eventually, the smaller broken material will be combined with organic material to become soil.

http://greenspade.com/how-to-collect-a-soil-sample


External forces that shape our planet

Chemical weathering occurs when rock is changed into a new substance as a result of interaction between elements in the air or water and the minerals in the rock.

http://www.shendapack.com/2011/04/27/chemical-weathering/


External forces that shape our planet

Decomposition, or breakup, can happen in several ways. Some minerals react to oxygen in the air and begin to crumble. That is when iron rusts, for example.

http://www.qub.ac.uk/geomaterials/weathering/causeway/geologicalsuccessiol


External forces that shape our planet

When sulfur and nitrogen oxides mix with water, acid rain is formed. The increase of acid rain in the 20th century is believed to be speeding up some decomposition.

http://www.cvgs.k12.va.us/research/final/sresch02/eevans/lit reviw.htm


External forces that shape our planet

The location and the climate in which the rocks are located have a great deal to do with how rocks decompose.

http://www.aralam.com/html/geology.htm


Climates that are warm and moist will produce more chemical weathering than do cool dry areas

Climates that are warm and moist will produce more chemical weathering than do cool dry areas.

http://www.qwickstep.com/search/chemical-weathering-examples.html


External forces that shape our planet

Rocks in cold dry and hot dry areas generally experience more mechanical weathering than chemical weathering.

http://geoimages.berkeley.edu/GeoImages/Johnson/Landforms/RocksWxing/ChemicalWxingGranitel


Erosion occurs when weathered material is moved by the action of wind water ice or gravity

Erosion occurs when weathered material is moved by the action of wind, water, ice, or gravity.

http://www.grundfos.com/service-support/encyclopedia-search/erosion-corrosion


External forces that shape our planet

For erosion to occur, a transporting agent, such as water, must be present. Glaciers, waves, stream flow, or blowing winds cause erosion by grinding rock into smaller pieces.

http:[email protected]/3810438780/


External forces that shape our planet

Material moved from one location to another results in the lowering of some locations and increased elevation in others.

http://www.uvm.edu/~inquiryb/webquest/sp09/mbeattie/Erosion by wind.html


External forces that shape our planet

For example, water might carry topsoil from a hill into a river and gradually cause the river to become more narrow.

http://savethesheyenne.org/erosion.htm


External forces that shape our planet

Erosion in its many forms reshapes landforms and coastal regions, as well as riverbeds and riverbanks.

http://www.dinsdale.co.uk/regeneration_water_courses.cfm


One form of water erosion occurs as water flows in a stream or river

One form of water erosion occurs as water flows in a stream or river.

http://www.sandhillstaskforce.org/Photo_Essay/Temp_sandhills_photos


External forces that shape our planet

The motion picks up loose material and moves it downstream. The greater the force of water, the greater the ability of the water to transport tiny rock particles, or sediment.

http://www.thefrancisgallery.com/photosn2.php


External forces that shape our planet

Another form of erosion is abrasion, the grinding away of rock by transported particles. The heavier the load of sentiment, the greater the abrasion on the banks and riverbed.

://geology.about.com/od/geoprocesses/ig/mechweathering/abrasion


External forces that shape our planet

A third eroding action of water occurs when the water dissolves chemical elements in the rock. The composition of the rock changes as a result.

http://pulse.pharmacy.arizona.edu/9th_grade/culture_cycles/earth_science/erosion.html


External forces that shape our planet

Most streams erode both vertically and horizontally, that is, the valley cut by a stream gets deeper and wider, forming a V-shaped valley.

http://www.aegweb.org/i4a/pages/index.cfm?pageid=4083


External forces that shape our planet

As the water slows, it drops the sediment it is carrying. When a river enters the ocean, the sediment is deposited in a fan-like landform called a delta.

http://geographyfieldwork.com/CrowdedCoasts.htm


Wave action along coastlines also changes the land waves can reduce or increase beaches

Wave action along coastlines also changes the land. Waves can reduce or increase beaches.

http://www4.ncsu.edu/eos/users/c/ceknowle/public/chapter12/part1.html


External forces that shape our planet

Sediment deposited by wave action may build up sandbars or islands. Wave action is so powerful that in some locations, it erodes about three feet of beach per year.

http://www.geograph.ie/photo/369272


External forces that shape our planet

For some unfortunate people, a beach house with an ocean view may end up in the ocean as a result of wave action erosion.

http://www.learnnc.org/lp/editions/cede_sealevel/366


External forces that shape our planet

In many ways, wind erosion is similar to water erosion because the wind transports and deposits sediment in other locations.

http://oceanworld.tamu.edu/resources/environment-book/aeoliantransport


External forces that shape our planet

Wind speeds much reach 11 miles per hour before fine sediment can be moved. The greater the speed of the wind, the larger the particles moved.

http://www.omafra.gov.on.ca/IPM/english/soil-diagnostics/erosion


External forces that shape our planet

Dust storms are capable of carrying as much as 6,000 tons of sediment per cubic mile of air. As the wind slows, the sediment is dropped.

http://www.pssac.org/SoilTeachingUnit/daytwo.htm


External forces that shape our planet

Depending on the type of windborne sediment, new landforms, such as sand dunes miles from seashores and rocks sculpted into fantastic forms, may be produced.

http://www.phototravels.net/egypt/egypt-v/egypt-v-072.html


External forces that shape our planet

Deposits of loess, windblown silt and clay sediment that produce very fertile soil, are found across the world. In northern China, for example, the deposits are several hundred feet deep.

http://www.pbase.com/dougsherman/image/93270863


External forces that shape our planet

Extensive areas of loess are found in the Mississippi Valley in the United States and in the grasslands of Argentina.

http://www.igsb.uiowa.edu/browse/loeshill/loeshill.htm


A glacier is a large long lasting mass of ice that moves because of gravity

A glacier is a large, long-lasting mass of ice that moves because of gravity.


External forces that shape our planet

Glaciers form in mountainous areas and in regions that are routinely covered with heavy snowfall and ice.


In mountain regions glaciers move downslope as a result of gravity

In mountain regions, glaciers move downslope as a result of gravity.


External forces that shape our planet

Glaciers such as ice caps and ice sheets move from the highest point on land toward the lowest point.

http://newglobalwarmingeffects.com/2009/11/16/disappearing-arctic-ice-caps/


External forces that shape our planet

Glaciation is the changing of landforms by slowly moving glaciers. As a glacier moves, several types of erosion occur.

http://web.arc.losrios.edu/~borougt/GlaciationDiagrams.htm


External forces that shape our planet

Rocks caught underneath the glacier are ground into finer and finer particles. Some particles are so small that they are called rock flour, which is one component of soil.

http://ana20cristina.blogspot.com/2009/03/gif-letras-numeros-y-simbolos-en-rombos_4508.html


Massive glaciers also cut u shaped valleys into the land

Massive glaciers also cut U-shaped valleys into the land.

http://ed101.bu.edu/StudentDoc/current/ED101sp09/sandra06/Valley.html


External forces that shape our planet

On top of or within the ice are other rocks carried by the glacier. When the glacier melts, these rocks are left behind.

http://serc.carleton.edu/details/images/22149.html


External forces that shape our planet

Rocks left behind by a glacier may form a ridge or a hill called a moraine. Moraines can be found on the sides, down the center, or at the leading edge of a glacier.

http://oceanworld.tamu.edu/students/iceage/iceage1.htm


External forces that shape our planet

Inside or under the glacier may be tunnels formed by running water. These tunnels fill up with sediment dropped by the water.

http://www.ens-newswire.com/ens/jul2010/2010-07-08-01.html


External forces that shape our planet

When the ice melts, it leaves a long snakelike ridge called an esker. Sometimes blocks of ice are trapped in the sediment. They melt slowly and leave behind a dent or a depression in the ground.

http://robinsonroom.blogspot.com/2010/06/glacial-features-photos.html


These depressions are called kettles the kettles may be filled with water forming a small lake

These depressions are called kettles. The kettles may be filled with water forming a small lake.

http://geology.about.com/od/glaciers_ice/ig/glacier-pictures/kettles


External forces that shape our planet

Weathering and erosion are a part of the process of forming soil. Soil is the loose mixture of weathered rock, organic matter, air, and water that supports plant growth.

http://www.mysciencebox.org/soilanalysis


Organic matter in the soil helps to support the growth of plants by providing needed plant food

Organic matter in the soil helps to support the growth of plants by providing needed plant food.

http://www.gardeninginfozone.com/organic-matter-for-the-garden


External forces that shape our planet

Water and air share tiny pore-like spaces in the soil. When it rains, the pores are filled with water. As the water evaporates, drains away, or is used by the plants, the pores are filled with air.

http://www.flickr.com/photos/dirkvdw/3752985815/


External forces that shape our planet

The texture of the soil, the amount of organic material called humus, and the amount of air and water in the soil all contribute to the soil’s fertility, its ability to nurture plants.

http://www.earthfort.com/products/supplies/denali-gold-humus


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