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Essential Science for Teachers: Earth and Space Science

Earth’s Solid Membrane: Soil Children’s Ideas About Soil

Children’s Ideas About Soil

Below are common ideas children in grades K-6 have about this topic, compiled from research on children’s ideas about science (see the Session 1 Children’s Ideas Bibliography).

Consider what evidence might refute this idea, and why a child would be likely to believe this? Once you’ve entered all your answers you can click “printable page” at the bottom of this form to be taken to a page with all your answers formatted for printing. You can also click “see possible response” for any question to see one possible response from the series content advisors.

1. Soil is ‘just dirt’ or ‘any stuff’ in the ground.

Soil is a complex combination of organic and inorganic materials, as well as air and water; it forms from the interaction of environmental factors.Children often interchange the words “soil” and “dirt” and use them as synonyms.

2. Soil is unchanging.

Soil is dynamic. It continuously undergoes changes caused by biological, chemical and physical processes. Soil can be repeatedly eroded, polluted, or rejuvenated. Children’s everyday experiences with soil, which are brief in terms of soil development, confirm their idea that soils do not visibly change.

3. Some children think that soil is quite young and has been formed in a few years; others think that soil is as old as the Earth.

With few exceptions, soils take hundreds to thousands of years to form.. Children do not generally understand that soils have different ages. Their ability to perceive time and the passage of time is limited. Also, many children think soil comes from plants, which contributes to the common misconception that soil is “just a few years” old. Some children perceive soil as an inseparable part of the Earth, formed when the Earth was formed.

4. Soil is brown and homogeneous. Twigs, leaf mold, and small stones are found in soil, and not an integral part of it.

There are many types of soils, each with differences in appearance and composition. Soil color ranges from yellows, browns, and reds to grays and blacks. Soil is a mixture of many diverse components, including live and decaying plants and animals and rocks at varying stages of weathering. Children’s experiences with soil — often garden soil — foster the idea that it is a single substance. Most children assume that all soil is the same as the soil with which they are familiar.

5. Soil does not contain air.

25% of soil is comprised of air. Air, as well as water, fills the spaces between soil particles, and is an integral part of soil that performs important functions. Air is gaseous and transparent, and its presence as a component within a solid, visible substance is not readily comprehended by children.

6. Many children think that they are living on land that is mostly soil, within which can be found masses of rock.

Childhood experiences may indicate that soil is the predominant material into which rocks are scattered. Under the relatively thin layer of soil, however, lies a solid unweathered layer of rock called bedrock.

7. Soil depth is anywhere from six inches to ten miles.

Soil depths vary from a few inches to over fifty feet. Children’s common experiences with soils, such as planting a garden or playing with mud, are limited to the soil surface. It is challenging for children to know about or visualize what they haven’t seen.



  • Happs, J. “Some Aspects of Student Understandings of Soil.” Australian Science Teachers Journal 28, no. 3(1982): 25 – 31.
  • Happs, J. “Soil Genesis and Development: Views Held by New Zealand Students.”
    Journal of Geography 83, no. 4 (1984): 177 – 180.
  • Driver, R., et al. “Materials and Their Properties.” Leeds National Curriculum Support Project, Part 3, Leeds City Council and the University of Leeds, U.K. (1992).
  • Russell, T., Bell, D., Longden, K. and McGuigan, L. Rocks, Soil, and Weather: Primary SPACE Project Research Report. Liverpool, U.K.: Liverpool University Press, 1993.

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Essential Science for Teachers: Earth and Space Science


Produced by Harvard-Smithsonian Center for Astrophysics. 2004.
  • ISBN: 1-57680-742-8