Soil Scrolls

Adapted from "The Story of Soil" from The Amazing Earth Model Book (Silver and Wynne, Scholastic Professional Books)

Lesson Introduction

Soil is composed of decayed plants and animals, minerals, and bits and pieces of weathered rocks. Soil provides many of the basic nutrients most plants use in order to grow. Earthworms, moles, ants and many other animals make their homes in the soil. As these creatures dig and move they loosen and mix the soil with air. Their movement, along with the movement of the wind and rain allow water to seep down into the soil as well and create further weathering of the rocks below.

Soil is comprised of three layers. First you find topsoil. This is the ground layer we walk upon, commonly referred to as 'dirt'. It is nutrient rich due to the decaying plant and animal matter, called 'humus', within. Beneath the topsoil we find the lighter colored subsoil. Subsoil is the middle layer that contains large rocks alongside minerals washed out of the topsoil. The final layer is the substratum, this is the deepest layer where rocks weather to form new subsoil. Beneath the substratum is the solid, hard bedrock, untouched by weather, plant or animal.

Illinois State Goal	Standard	Learning Benchmarks
12	B	1a. Describe and compare characteristics of living things in relationship to their environment.
12	E	1a. Identify components and describe diverse features of the Earth's land, water and atmospheric systems.

Lesson Objectives

The students will:

• identify and depict three different layers of soil
• identify the ways animal and plants use soil

Advance Preparation

Time Allotment

45-50 minute class period

Materials

per group:

• soil samples (see Advanced Preparation)
• clear tape
• two unsharpened pencils (optional)

per student:


• sheets of blank paper
• crayons

PROCEDURE

Tap Prior Knowledge

1. Ask students if they have ever dug into the soil. What did they find? What creatures live in the dirt? Tell the students that many living things use the soil as homes. Plants use the nutrients from rocks, minerals and decaying plants and animals as food to grow on. Worms, ants and moles dig tunnels deep down to use as homes and nests for babies. Tortoises may hibernate in winter within the deeper layers of the soil.

Share with Neighbor

2. Show each group the soil samples. Have them make some observations. Do all layers look the same? Have the pairs of students describe some of the differences in appearance. Why do they think the layers look different? The topsoil is darkest because it contains the rich humus (decaying plants and animals). The second layer of subsoil is lighter because it contains less humus and less direct impact from the weather. The substratum receives the least impact from the weather and is closest to the bedrock.

Hands-on Activity

3. Separate students into groups of four.

4. Give each student a piece of paper and crayons.

5. Each student will be in charge of drawing a different layer of the soil. The first student will draw a picture of what happens on top of the ground. Perhaps they will depict the flowers that we see on the ground, the birds that hop along the gound to feed off of the worms within, and the rocks and logs that rest on top.

6. Another student will be in charge of drawing an inside look at the topsoil. They can include the worms, ants and other creatures that inhabit the topsoil. They may also include some of the roots from the plants that flower above ground.

7. Have the third student depict the middle layer or subsoil. This will contain many rocks of different sizes and mineral contents. It may include deep reaching plant roots.

8. The last student will be draw the final layer of soil, the substratum. This will be the lightest color layer and have the very largest rocks.

9. When each student is drawing their section, have them tape together their drawings in order to create a long scroll-like picture.

10. You can attach unsharpened pencils at either end of the scrolls for a more formal appearance.

Introduce Scientific Principle/Environmental Issue

11. Ask students why they think the layers are different. Why does most of the 'action' happen in the topsoil layer? This is where the most nutrient rich soils are, and is closest to water, so plants and animals that need air, water and food (the soil's minerals) to survive want to be able to meet their needs.

Relate Activity and Concept

12. Have students compare and contrast scrolls. Do they resemble the soil samples that you brought. What would a plant or animal need in order to survive in the subsoil or substratum layers?

Learning Outcomes

Students will:

• identify and depict three different layers of soil.
• identify the ways animal and plants use soil.
• identify animal habitat needs.