Available Soil

Time - 15 minutes

Student Outcomes
The student, when given an apple, plastic knife and plate, will be able to follow the directions given by the teacher.

Materials

• globe
• large apple
• heavy plastic serrated knife
• paper towels
• paper plates

Vocabulary

• serrated

Focus

"Does anyone have any idea why I thought this was an important subject to teach?" Explain that soil is one of our most important resources. "Why do you think this is?" Explain that all living things depend on soil as a source of food either directly or indirectly. We need the soil to produce food, but we have a problem, our population is growing while the soil that is useful for this is diminishing. "What can we do to save our soil?" We need to use our soil wisely and protect it to ensure the future. Your apple is going to represent the earth like this globe represents the earth.

Note: The following activity is to show just how much of the earth's surface is actually used for our food production as compared to the growing population. Do the next activity while modeling it for the students.

Ask students to give properties of the plastic knife. (made of plastic, serrated and breakable) "The knife will cut you if not used properly. If you break the knife, ask me for another. So that we don't cut ourselves, this is how we will work with our materials today."

1. "Place apple on the paper plate."
2. "Cut the apple on the paper plate according to the directions to be given. Do not hold apple in your hand."

Procedure

1. "Cut the apple into 4 equal parts. Three parts represent the oceans of the world. Lay aside 3 parts on paper plate. The 4th part represents what?" (land areas)
2. "Cut the land section in half lengthwise. Now we have two one-eighth (1/8) pieces. One section represents land such as deserts, swamps, antarctic, arctic and mountain regions. Lay aside one section on the paper plate."
3. "Slice this remaining one-eighth (1/8) section crosswise into 4 equal parts. Three of these sections represent areas of the world which are too rocky, too wet, too hot, or where soils are too poor for production, as well as areas developed by man. Lay aside 3 pieces of the apple on the paper plate."
4. "Very carefully peel the last section which is one-thirty second (1/32) of the apple. (lay aside apple flesh) This small bit of peeling represents the soil of our earth on which mankind depends for food production."

"So we see that it is a very small portion of land. What should we do to this small portion?" (protect and conserve it)

"One problem we need to correct is soil erosion. Does anyone know what soil erosion is? When we have science again, we will see if we can discover what causes erosion."