Changes to the Earth's Surface

Changes to the Earths SurfaceA Look at How Landforms are the Result of Changes to Earths Surface by Water, Wind, and Ice

1Changes to Earths SurfaceStudents will focus on three landforms, how they are formed, and where they are located in Texas. Sand dunes, canyons, and deltasTEKS: 5.7; 5.7B; 5.2; 5.2A; 5.2C; 5.2D; 5.3; 5.3A; 5.4; 5.4A; 5.4BWind and stuffWhat kinds of things are moved by wind?How does it feel when a strong wind hits your bare skin?How does if feel if there is sand in the wind and it hits you?What is the texture of sandpaper like?How does sandpaper feel against your skin?Sand and windWhen strong winds blow in sandy deserts or beaches, the wind picks up pieces of sand and carries it to a new location. In this way, sand dunes are moved and reshaped with each strong wind. The force of the wind blowing the sand acts like sandpaper upon the rock it touches. The blowing sand particles weather and erode desert rocks, slowly changing their shape over time.http://www.bbc.co.uk/science/earth/surface_and_interior/erosionhttp://beyondpenguins.ehe.osu.edu/issue/earths-changing-surface/the-forces-that-change-the-face-of-earth

What is a Landform? In your science notebook, write a description of how you would describe a landform to another student.

Although there are many different landforms, in this lesson, we will focus on three specific landforms.

Canyons

Photo credits:Matakatamiba Canyon; http://office.microsoft.comBighorn Canyon; http://office.microsoft.comGrand Canyon; http://office.microsoft.com

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Sand Dunes

Photo credits:Gobi Desert; http://office.microsoft.comSahara Desert; http://office.microsoft.comCoastline, Lighthouse; http://office.microsoft.comMonahans; Wiki-commons10

Weathering, Erosion, and Deposition by Wind

Sand dunes form by

Sand dunes change by

15The upper picture shows dunes that are formed and changed by wind. The lower picture shows dunes that are created and changed by wind as well. Students may observe that the sand along the coast may also be moved by waves (water).

Upper left photo: dunes near Monahans, Texas (Photo: Monahans: Wiki-commons)Lower right photo: Port Aransas, Texas. (Photo: A. Venegas)

Weathering, Erosion, and Deposition by Wind

The wind reshapes the rock byUpper photo: Arches National Park, Utah (photo: Arches National Park; http://office.microsoft.com)

Lower photo: Chihuahuan Desert, Big Bend, Texas (photo: Wiki-commons)16WaterWhen it rains, and water is flowing, what happens to the soil on our playground, in your yard, or around the neighborhood?

When it rains and the road floods, why do the police put up the barricades warning people to stay away from the flowing water?Running WaterRunning water is a powerful forceRunning water is powerful enough to move large amounts of soil or sediment from one location to another.Water that continually runs over rock causes it to weather and erode, creating canyons, sea arches, or sea caverns over time.Sediment that is carried by running water can be deposited at the mouth of a river, forming a delta over time. Famous Landforms by WaterThe Grand Canyon has been carved by the Colorado River for 17 million years. The width of the canyon ranges from four to 18 miles and is 277 miles in length. The first Europeans to visit the Grand Canyon were conquistador Francisco Vazquez de Coronado and Captain Garcia Lopez de Cardenas who were helped by Hopi Indian guides.

Read more: Famous Landforms | eHow.com http://www.ehow.com/list_7633909_famous-landforms.html#ixzz2DNkPn3bj

The Grand Canyon

Weathering, Erosion, and Deposition by Water

Flowing water changes the rock by

Upper photo: Niagara River, Canada (Photo: A. Venegas)

Lower photo: Whirlpool Rapids Bridge (Photo: Wikimedia Commons)

21Weathering, Erosion, and Deposition by WaterCanyons form byCanyons change over time by

Upper photo: Active gully erosion to the west of Broadford, Australia, after recent heavy rains(Photo: http://www.dpi.vic.gov.au/agriculture/about-agriculture/newsletters-and-updates/sheep-notes-newsletter/autumn-2011)

Lower photo: Fjarrgljfur canyon near Kirkjubaejarklaustur, Iceland (Photo: pjt56; http://en.wikipedia.org/wiki/File:Fjadr%C3%A1rglj%C3%BAfur-pjt.jpg)22DeltasA delta is formed at the mouth of a river. It is often a triangular shape. Sediments -- silt, sand and small rocks -- flow downstream. These materials are deposited in a fan shape where a river meets a lake or the ocean. Many famous delta landforms are found worldwide. Major river systems create the largest deltas. These landforms create fertile areas conducive to fishing, farming and human settlements.

Read more: Famous Delta Landforms | eHow.com http://www.ehow.com/info_8258472_famous-delta-landforms.html#ixzz2DNk5jeMZ

Famous DeltasMississippi River Delta - Shows its characteristic bird's-foot pattern and plumes of sediment entering the ocean from the multiple mouths of the Mississippi River.The lower picture is of the Nile River Delta.

River Deltas

Mississippi River Delta - Shows its characteristic bird's-foot pattern and plumes of sediment entering the ocean from the multiple mouths of the Mississippi River.The lower picture is of the Nile River Delta.Pictures courtesy Wiki-commons.

25Erosion and Deposition by Water

Deltas form byDeltas change over time byUpper photo: Atchafalaya River Delta, Louisiana (Photo: Wikimedia Commons)

Lower photo: Wax Lake Delta, Louisiana (Photo: Wikimedia Commons)

26WaterWAVESHave you ever been in the ocean or felt the force of a wave hit you or have you been in a wave pool at a water park?

How powerful did the waves feel?

If you have been to the beach, where do you think all the sand came from?WAVESAs waves repeatedly crash into rocks along the shoreline, it can weaken the softer rock. This weathering by waves can break the rock causing it to erode and crumble into smaller rocks.Sometimes, when softer rocks are eroded away, it can create sea caves, sea arches, or sea stacks. Over a long period of time, the force of the waves can weather the smaller rocks into grains of sand. Weathering, Erosion, and Deposition by Water (Waves)

Waves change the rock byThe upper picture shows wave action on a cliff. The landform has changed from a cliff to a sea arch. The lower picture shows the coast in Galveston, Texas that has been eroded by waves. A question to ask students might be: what might be the consequences if wave action continues over time?

Upper photo: Wave erosion on a Portland Cliff (Photo: Nigel Chadwick; http://commons.wikimedia.org/wiki/File:Wave_erosion_on_a_Portland_Cliff_-_geograph.org.uk_-_109895.jpg)

Lower photo: Beach erosion along Galvestons beaches. (Photo: FEMA)29Weathering, Erosion, and Deposition by Water (Waves)

Over time, waves can change

Upper photo: Cathedral Cove, New Zealand (Photo: C. Mackenzie)

Lower photo: Swanlake Bay wave cut platform (Photo: Sid Howells; http://www.geograph.org.uk/photo/1570744 )30Ice ActionA glacier is a mass of ice that stays frozen throughout the year and moves slowly downhill. When a glacier moves across land, it acts like a giant bulldozer.In most instances, a glacier must be 59 feet thick to begin to move. Ice ActionAs gravity causes the glacier to move, the glacier pushes and covers rocks, soil, and other debris. Some of the rocks, soil and debris scrape against the surface of the land and sometimes it is pushed to the side of the glacier. Once the glacier begins to melt, rocks, soil, and other debris is left behind.The weight and pressure of the glacier can carve out U-shaped valleys.Ice ActionAs glaciers move, they can make deep, parallel scratches or grooves, called striations, in the surface of rock too large to move.Water can seep into cracks in the rockIf the water freezes, it will expandThis action pushes against the sides of the cracks, weakening the rock. If the freezing and thawing cycle is repeated often, the rock will break at the crack.Erosional/Weathering Agent: Ice

Ice can change rock by

Upper photo: Hurricane Ridge, Washington (Photo: A. Venegas)

Lower photo: Milford, New Zealand, cool green glacial lake in mountaintop (Photo: C. Mackenzie)

34Erosional/Weathering Agent: Ice

Mountains can be reshaped by

The upper photo shows how a U-shaped valley has been carved in a mountain by ice (glacier). The lower photo shows the reshaping of a mountain through exfoliation. Water has seeped into cracks, and through years of heating and freezing, the layers of rock have cracked and moved down the landform.

Upper photo: Alpspitze and Zugspitze mountain (Photo: http://office.microsoft.com)Lower photo: Enchanted Rock (Photo: Wikimedia Commons) 35Famous Glacier

The most famous Glaciers in the Arctic Circle is Okstindan and Svartisen. In winter it can fall more than 10 meters of snow in the Arctic Circle area of Norway.

Landforms on EarthAre all Earths landforms the same? Why or why not?

What are some of the features that you see when you look at the pictures?

Do you think that these landforms have always been the same?

Do you think that changes in these landforms occurred quickly or did they take a long time to be formed?

37Are all Earths landforms the same? Why or why not? No, Earth has different landforms. Answers may vary on the why responses.What are some of the features that you see when you look at the pictures? Answers may vary.Do you think that these landforms have always been the same? NoDo you think that changes on these landforms occurred quickly or did they take a long time to be formed? It took time for these landforms to occur.

Landforms on EarthHow will these landforms look:Two days from now, one year from now? Ten years from now? One hundred years from now? One thousand years from now?One million years from now? Which forces caused these landforms to change?

How do the landforms that are formed and changed by water, wind, and ice differ from each other?

How will these landforms look two days from now? One year from now, ten years from now? Very little noticeable change. One Hundred years from now? Change can begin to be noticeable. One thousand years from now? Most will change in size and shape over many years. One million years from now? There may be large amount of change.What force/action caused these landforms to change? Energy from wind, water, and ice caused the changes.How do the landforms that are formed and changed by water, wind, and ice differ from each other? Yes, canyons and deltas are caused by water, and sand dunes by blowing wind. Ice, in the form of glaciers, can carve rocks or cause them to crack.38Landform DefinedIn your science notebook, write a definition for the word landform.

Landform - Any feature on the Earth's surface, caused by erosion, sedimentation, or movement of material by wind, water, or ice

Teacher note: Do not click after the first sentence comes in. Allow time for students to write a definition before giving them a formal definition.

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