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What Is Soil Made Of?

Author(s): Nancy Moreno, PhD, and Barbara Tharp, MS.

Let's Talk About It

This activity enables students to learn about soil by exploring a sample of natural soil and identifying and separating its different components. During this activity, students discover that soil contains both living and non-living components. 

Stimulate a discussion about what students observed by asking, What are some of the things that you saw in the soil? Soil samples may contain twigs, pieces of leaves, plant roots, insects, worms, small rocks and particles of sand. Then ask, What are some things in soil that we can’t see? Answers may include air, water and microorganisms. Invite students to share their observations. 

Ask, How many different layers did you find? What was on the bottom? What was on the top? The heaviest particles, such as sand and rocks, usually will make up the bottom layer, followed by fine sand and silt. Some clay particles are so tiny that they will remain suspended in the water. Plant and animal material also may float at the top of the water. You also might ask, What do you think is the primary component of soil?

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932