Lesson 1: Soil

Getting Started

Questions to Explore

  • How is the soil dependent on living things?
  • How are living things dependent on the soil?

Facts and Definitions

  • Soil is made up of sand, silt, gravel, clay, and organic matter (rotting things that were once living, i.e., dead leaves and twigs).
  • The layers of soil include humus, topsoil, subsoil, and parent material.


  • Observe and describe the properties of soil: color, texture, and capacity to hold water. (S)
  • Investigate and observe that different soils absorb water at different rates. (S)
  • Determine the ability of soil to support the growth of many plants, including those important to our food supply. (S)
  • Identify the basic components of soil: sand, clay, and humus. (S)


  • Dirt by Steve Tomecek
  • 2-liter soda bottle
  • 4 zip top bags
  • 6-inch square of thin cloth (kit)
  • blindfold
  • clay soil (kit)
  • colored pencils or markers
  • dirt
  • grass seed (kit)
  • gravel (kit)
  • large rubber band (kit)
  • measuring cup
  • measuring spoons
  • paper towel
  • plastic cups (kit)
  • potting soil (kit)
  • sand (kit)
  • Science journal
  • scissors
  • sharp pencil
  • silt or flour
  • spray bottle with water (kit)
  • Styrofoam cup (kit)


Materials: dirt
Give your child a cup of dirt and encourage him to share what he knows about dirt. Ask him why it is one of the most important resources on the planet.
Reading and Questions
Materials: Dirt by Steve Tomecek
Encourage your child to read the book, Dirt, aloud. Ask him the following questions when he has finished reading the book.
  1. Why is dirt important?
    It's a natural resource that supports life on Earth. It supports our food supply and provides foundations for roads, buildings, and homes.
  2. What are the components of soil?
    Gravel, sand, silt, clay, and organic matter.
  3. How is soil made?
    Rain, ice, and wind wear rocks into smaller pieces called sediments. The four types of sediments combine to make soil.
  4. What is organic matter, and why is it an important part of soil?
    It comes from living things like twigs and dead leaves. When organic matter rots, it puts nutrients into the soil.
  5. What lives in the soil? How are they dependent on the soil? How is the soil dependent on them?
    Many different things like critters, microbes, and worms live in the soil. Worms eat the dirt for food. They excrete loose, fluffy soil enriched with nutrients. They also dig tunnels in the soil, making spaces for water and air.
  6. Why is soil important to people? Why could people not survive without soil?
    Soil lets plants grow, and plants provide food and oxygen for us to live. Animals eat plants, and animals provide us with food, too. Without food or oxygen, we couldn't live.
  7. Describe the four layers of soil.
    Humus is the fluffy top layer made up of dead plants and leaves. Topsoil is the layer where plants put their roots. Subsoil is heavy and hard to dig. Parent material is rocky and hard, and it provides good support for building foundations.