Humans, the Environment, and the Great Plains

Battlefield Earth: Geological Forces in Action

Background:

The land we live on is like a battlefield. On one side of the battle are the forces beneath the surface of the earth like gravity, earth movement, volcanic pressures and the like. These forces cause the crust to be faulted, folded, tilted, and lifted. On the other side of the battle are the natural processes of weathering and erosion. Once rock has been broken up by weathering, the small pieces can be moved by the action of water, ice, wind, or gravity on these rock pieces. Everything natural that happens to cause rocks to be carried away is called erosion. The purpose of the activities outlined in this lesson plan is to increase students' awareness to the point where they can make intelligent decisions on proper land use.

Objective:

The objective of this lesson plan is to have the students:

  1. Identify the different types of erosion.
  2. Identify the effect of ice on land.
  3. Identify the effect of wind on land.
  4. Identify the effect of water on landforms.
  5. Apply all of the above information to the changing environment of the Great Plains.

Plan:

Sand dunes: How are they formed?

  1. Have the students place some sand in a pile and blow gently on it from one side. Ask them to observe what happens when they blow on the sand pile. Can the students make the whole pile move if they blew on it long enough?
  2. This activity demonstrates the effect of wind on sand and the resultant formation of sand dunes.

Windblown deposits:

  1. Ask the students to collect the following: old newspaper, dry sand in a jar with lid, box lid, spoon, water, paper, and pencil.
  2. Have them unfold the newspaper and place the box lid on it. Then ask them to remove the lid from the sand jar and pour some sand in the jar lid. Place the jar lid with sand in the center of the box lid.
  3. Ask students to blow gently on the sand in the jar lid. They should then increase the strength of their breath until the sand is being thrown from the jar lid onto the box lid and the newspaper. Students should continue blowing for 5 to 10 seconds at this rate.
  4. Have the students examine the sand on the newspaper by rubbing their fingers over it. They should do the same to the sand trapped in the box lid. Ask them which sand is finer and why. (The sand on the newspaper will be finer than that in the box lid because the former spreads out more thinly while the latter is confined by the box lid). Windblown deposits scatter far and wide over open spaces and pile up in confined areas.

Erosion due to water weight:

  1. This activity will teach students how the weight of water affects the earth.
  2. Ask students to find a spot of bare, dry earth. Then have them pour a cupful of water on it. Repeat the pouring on the same spot, but this time have them hold the cup from as high a distance as possible.
  3. Ask students to observe how the earth changed when they poured the first cupful of water on it. Then, ask them to observe what happened when water was poured from a greater height. Can students relate this phenomenon to changes caused by the weight of water in various places around the earth?
  4. Water poured from a greater distance will disperse more dirt on the ground than water poured from a lesser height. Similarly, various areas of the earth are affected by different weights of water in different ways.

Landslides:

  1. This activity will focus on landslides and the cause (s) behind the phenomenon. Hills and mountains that seem very solid and stable in dry weather develop major landslides after prolonged rains. What causes such landslides to happen?
  2. Students will build a small sand castle in a small sandbox (substitute with a cardboard box if sandbox is not available).
  3. Ask the students to pour some water over the sand castle till the sand can absorb no more water. Have them observe what happens to the castle as more and more water is poured over it.
  4. The sand castle will begin to disintegrate and crumble as water is poured over it till there remains nothing but a shallow pile of sand. Ask the students to compare this activity to rainfall and the effect it has over mountains and hills over a long period of time. Landslides can be caused by prolonged rainfall over hills and mountains.

Testing, Grading, and Evaluation:

All the activities outlined above demonstrate that the natural process of erosion works slowly but surely. Over a period of time, erosion can wear away a mountain until it is level with the plains. Short term effects of erosion are evident in river cutbanks, hillsides, and gullies. Erosion can strip the earth of valuable mineral-laden top soil, which harms agriculture.

The more that students know about the causes and prevention of erosion, the more they can do to wisely use the land and not destroy or misuse it.

Adapted from Lesson Plan by Dorothy Stetsko, West Park Elementary, Fresno, California

Primary Course: Social Studies

Applicable Grades: 3 - 5

Materials Needed: Listed in the main text of the lesson

Related Courses: Geography

Time Required: 1 - 2 hours

Return to Main Lessons Page
Buffalo Shield Icon Return to Main Environment Page

©Archaeology Laboratory, University of South Dakota