# This is a good lesson on Gravity, Erosion, and Mass Wasting

Subject:

Science

8

Title – Gravity and erosion
By – Andy Field
Primary Subject – Science
Secondary Subjects –
Earth Science
Gravity and Mass Wasting

Goal: TLW understand how gravity affects erosion and deposition.

Objectives: TLW explain how gravity affects erosion and deposition, TLW differentiate between rapid and slow mass wasting.

Set: Place a ball on the table. Ask what happens (nothing). Place ball on slanted surface. Have students predict what will happen (it will roll down) . Ask what would happen if the ball were placed at the top of a mountain.
Explain that gravity causes all the downhill movement of sediments.

Review: In the last chapter we learned that weathering is what breaks down the earth’s surface. Yesterday we learned that erosion and deposition are how the broken down particles are moved. Today we will learn about one agent of erosion and deposition: Gravity.

Procedure: Write objectives, rapid mass wasting, slow mass wasting, talus slope on board. Explain that the downhill movement of sediments is called mass wasting. Have students give examples of mass wasting and write them on the board. Examples of rapid mass wasting are landslide, mudflow, and slump. Slow mass wasting: earthflow and soil creep. Explain these. Explain that when particles move downhill, they form what is called a talus slope. Students will better understand mass wasting after the following activity: Explain it first, then divide the students into groups.

Activity: In a large tray, construct a model mountain from soil and rock. Shake the tray to simulate an earthquake. Observe what happens. Rebuild the mountain. Pour water on it to simulate a rainfall. Observe what happens. On a blank piece of paper, answer these 2 questions: How did the water cause the mountain to erode? In both the rainfall and the earthquake, what happened to the particles that moved downhill? Clean up your area and return to seats.

Closure: Have students explain erosion and deposition. Have them give examples of rapid and slow mass wasting, explain how gravity affects erosion and deposition. Tell students that tomorrow we will learn about the second agent of erosion and deposition: Wind

Evaluation: Observation of student participation and understanding, written work from activity, written test Friday.

Materials Needed:

Large trays
Soil and Rock
Water containers and water
ball

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