Weathering & Erosion

Science Concepts TEKS 7.14 The student knows that natural events and human activity can alter Earth systems. The student is expected to: (A) describe and predict the impact of different catastrophic events on the Earth; (B) analyze effects of regional erosional deposition and weathering

Learning Objectives The learner will be able to identify erosion. –identify effect of chemicals on land. –identify effect of wind on land. –identify effect of ice on land. –identify effect of water on land. –identify effect of temperature on land. The learner will explain the causes of erosion. The learner will compare the effects of different types of erosion The learner will predict the outcomes of various means of erosion. The learner will analyze the effects of regional erosional deposition and weathering by looking at photographs of the Grand Canyon's rock layers

Engage Mudslide Flooding

Explore 1 Take a potted plant out of the pot, with soil intact. Discuss how the roots of the plant help to hold the soil in place. Ask what would happen if the plant was not in a pot, but in the ground and water keep running over it. Introduce the term erosion and discuss how wind, water, and ice can cause erosion. Ask students if and where they have ever seen the effects of erosion. Explore and examine the effects of erosion on the school grounds and surrounding school property. Ask students to remember how plants hold soil and to pay special attention to the placement of trees and shrubs on the school grounds. Students will be asked to take a pencil and notebook to write and draw evidence of erosion on the school property. Point out evidence of erosion on the school grounds. Some good examples are often near drains, drain pipes, and at the edges of the blacktop.

Explain After students are back in the room, ask them to share what they have written in their journals about the effects of erosion on the school property. Ask if anyone noticed the placement of trees and shrubs. Ask the students if the trees and shrubs were placed in particular areas to help stop the effects of erosion.

Review the term erosion and how plants help stop erosion. A discussion of deforestation would also appropriately follow this lesson. Discuss the forms of erosion that were witnessed on the school property. Explain that most of the erosion that was witnessed on the playground was caused by water.

Flooding

Sea Arches

Beach Erosion

River Erosion

Mudslide

Explore 2 Weathering Stations Station 1. Test rock samples in carbonated water vs. tap water. Observations are taken initially, at 20 minutes, and after 24 hours. Station 2. Test to show that water expands as it freezes. Mark on a cup the water level before freezing and after freezing. Station 3. Test the effects of vinegar (acid rain) on copper (pennies). Here you should record observations initially and then after 5 minutes. Station 4. Compare and record the reaction of antacid tablets in water. The comparison is a whole tablet vs. crushed tablet. Station 5. Compare and record the reactions of chalk (limestone) in water and vinegar.

Explain How does weathering and erosion occur? What is the result of each type of weathering? Where on earth or where in Texas does this happen?

Explore 3 Erosion Stations Station 1: Water Erosion 1. Before class form a mound of nonoily clay into a level mass about 5-10 centimeters across and place it into a tray or large pan. 2. Pebbles, coins, and plastic chips will be pressed into the top surface of the clay. 3. The entire class should you outside where the clay mound will be lightly sprayed from above. 4. Students should note in their science journals how the spray washes away the clay while the pebbles, coins, and plastic chips cause pinnacles to form. They should be able to infer that the harder surfaces are more durable in the face of water erosion. Questions: - What caused the clay to run off? - Why did the pinnacles form? - What other materials might have protected the clay? - Can you think of any examples of such pinnacle formations in nature? - What other examples of water erosion can you think of?

Explore 3 Erosion Stations Station 2: Beach Erosion Using a pan, make a sand pile at one end and pour water at the other end. Slide the pan back and forth to create wave movement. Record observations.

China’s Yellow River The 1887 Yellow River floods devastated the area, killing between 900,000-2,000,000 people. It was one of the deadliest natural disasters ever recorded. For centuries, the farmers living near the Yellow River had built dikes to contain the rising waters, caused by silt accumulation on the riverbed. In 1887, this rising riverbed, coupled with days of heavy rain, overcame the dikes, causing a massive flood. It was one of the worst floods in history, though the later 1931 Yellow River flood may have killed as many as four million people. Much of the problem stems from the high silt content of the river - - in some stretches as much as 60% by weight. Millions of tons of yellow mud choke the channel, causing the river to overflow and change course. In its lower reaches, the river bed has actually become higher than the level of the surrounding countryside. Water is held in by dikes of ever increasing height, some reaching 30 feet and more.

Explore 3 Erosion Stations Station 3: Glacier Erosion 1. Students will press an ice cube against the flat surface of modeling clay and move it back and forth several times and record observations. 2. Students should then place a small pile of sand on the clay. The ice cube should be placed on top of the sand and left for one minute. 3. Students should then pick up the ice cube and observe the surface of the cube that was touching the sand and again record their observations. 4. The same side of the ice cube should then be placed on the sandy part of the clay and moved back and forth several times. 5. The ice cube should be removed, the sand should be wiped away from the surface of the clay, and the clay's surface texture should be recorded. Questions: - What happened to the clay the first time you wiped the cube against it? - What happened to the ice cube after it sat on the on the sand? - What did the surface of the clay look like after you rubbed the cube against it the second time? - Does glacial erosion still occur today or is it just an ice age phenomena? - Can you give any examples of Glacier erosion?

Hubbard Glacier in Alaska

Matterhorn in Switzerland, a geographical anomaly produced by glaciers

Explore 3 Erosion Stations Station 4: Wind Erosion 1. Every group will have a box with its top and one side removed. A pile of sand will then be formed in the center of the box bottom. 2. Students will be instructed to use a hair dryer to lightly blow over the sand from the open side of the box. Note if different speeds are possible. 3. Students will record their results. 4. Students will then be asked to reform their sand piles and will be given a choice of materials (water, plastic chips, pebbles, coins) to choose from to try and prevent the sand from moving. 5. Students will again be instructed to blow and record their observations. Questions: - What happened to the sand as you blew? - Could you make the whole pile move if you blew long enough? - What materials did you choose to add to your reformed piles and why did you choose these materials? - What was the effect after you added these materials and blew? - Can you think of any examples of wind erosion in nature?

Sahara Desert

Kalahari Desert

Gobi Desert in China

Dust Bowl, the man-caused environmental disaster of the 1930s

Elaborate Brainstorm how you think the Grand Canyon was formed.

Elaborate

Test Your Knowledge Grand Canyon Brainteaser

Elaborate How many different layers can they count? How many different colors do they see in the layers? Why do they think the layers look different from each other? Students should recognize that the layers are different because different types of rocks and sand were deposited at different times. Ask students if they can find the Colorado River at the bottom of the canyon in this photograph. Explain that over several million years, this river eroded the rock layers and made it possible for us to see them. The river once flowed at the top layer but now flows where we see it today.

Horseshoe Bend

Evaluation Create a brochure to entice visitors to the Grand Canyon. Recent vocabulary and grammar will be stressed. A section discussing the formation of the canyon will also be mandatory. Students will also be encouraged to use information which will focus on the native American Anasazi cliff dwellers and other native Americans of the region, including the Havasupai. Students will be allowed to use the Internet, books, or information from other classes (social studies) to complete this assignment.

Thanks to: Images Canadian Landscapes drake.marin.k12.ca.us/.../Title%20Page.html Lesson Ideas Source: Stetsko, Dorothy. Encarta Schoolhouse. "Erosion." (encarta.msn.com/alexandria/templates/lessonFull.asp?page=351).