Chapter 12, Lesson 4, "Erosion Caused by Wind and Gravity"

Materials:

• Worksheet, "Erosion Caused by Wind and Gravity" Crossword.

Objective:

• Students will describe how wind erodes land.
• Students will explain how sand dunes form.
• Students will identity examples of erosion by gravity.

Anticipatory Set:* Teacher will set up a box with sand in the bottom. A hole will be put in the side the size of a hair dryer nozzle. A small pebble will be put in the box to create a dune when the hair dryer is turned on. Students will observe how the hair dryer moves the sand around. Show this animation of sand particles and ask if it shows the same thing seen in the demonstration. Then show the same animation close-up.

Teacher Input:* Show the students an animation of a dust storm and ask, in what part of the world does wind erosion move the most soil? Why? (Arid regions because of little vegetation and dry soil) Show pictures of desert areas to explain this: desert 1, desert 2, desert 3. Point out the did you know box on page 300. Show the students a world map of the desert. It covers 9 million kilometers but is not all sand. Show rock formations in the Sahara.Sahara 1, Sahara 2, Sahara 3. The wind has a great ability to move this material. Dust is easily moved and can be carried for miles. DustStorm1, Duststorm2, Dust devil. Sand is a little bigger and doesn't blow as easily but can still be moved hundreds of miles.SandStorm1. As these particles hit other rocks they can further weather that material. Sand weathering.

Gravity also is an important factor in Erosion. Even if there is no wind, glaciers, rain gravity can still cause landslides. They can occur because of earthquakes, floods, and volcanic eruptions. Freezing and thawing can loosen material and then it may fall causing an avalanche of soil and rocks especially if the soil is moist and slides easily. Gravity also works slowly. Rocks, soil, and debris may slide downhill slowly tilting objects on the soil slowly. slump 1, slump 2, slump 3.

Guided Practice:* Each site will get the opportunity to answer one question from Page 302.

Independent Practice:* Students will complete the worksheet, "Erosion Caused by Wind and Gravity: Terms Review"

Check for Understanding:* Students will complete the quiz over lesson 4, "Erosion Caused by Wind and Gravity"

Duration:

30 minutes + 10-15 for Independent Practice (Could be longer if taken for homework).

Alaska Content Standards Addressed in this lesson:

• SCI A-7 Students will understand how the earth changes because of plate tectonics, earthquakes, volcanoes, erosion and deposition, and living things (Processes that Shape the Earth);

• SCI A-15 Students will use science to understand and describe the local environment (Local Knowledge); and:
• SCI B- 1 Students will use the processes of science; these processes include observing, classifying, measuring, interpreting data, inferring, communicating, controlling variables, developing models and theories, hypothesizing, predicting, and experimenting;