To define the terms buffer strip, terraces and contour farming.
To apply the skills of observation to interpret visual materials as sources of information.
To explore the causes and effects of soil erosion and water pollution.
Students will examine an aerial photograph of a terraced farm field. The clue questions will introduce students to the terms terrace, buffer strip and contour farming. In Iowa, terraces and buffer strips are used to prevent the run-off that destroys topsoil and pollutes streams and rivers.
During the follow-up activity students will be introduced to terracing as a farming practice throughout the world. In many locations and climates for thousands of years, people have farmed the slopes of mountains and hills by creating terraces.
As an application of these concepts, students will make observations of Stone City, an important and famous painting by Grant Wood. Students should apply sound principles of contour farming when observing the painting. Then they will draw their own version of the painting by adding contour farming with terraces and buffer strips.
Introduce the terms cause and effect. Discuss the fact that for every event or decision, there are multiple effects. Provide examples such as the following:
Flooding along rivers and streams
Choosing to smoke cigarettes
Increased risk of lung cancer
Working hard on school assignments
In addition to initial effects, there are also ripple effects. For example, heavy rains result in flooding along rivers and streams that in turn, results in evacuation of people living along the streams, etc.
Distribute to teams of students a blank copy of the Decision Wheel. Have students write the words "Soil Erosion and Pollution" in the center of the wheel.
Using online resources students will identify the consequences and ripple effects of soil erosion.
When students have completed their charts, provide time for groups to share their work. A sample completed Decision Wheel has been provided as a guide for discussion.