Lesson 6: Compost and Decomposers

Getting Started

Questions to Explore

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

Facts and Definitions

  • Decomposition is the process by which dead plants and animals are broken down into simpler substances.
  • Decomposers are the living things that break down dead plants and animals in the soil.


  • Observe and measure how the quantities and qualities of nutrients, light, and water in the environment affect plant growth. (S)
  • Determine how composting recycles discarded plant and animal material. (S)
  • Determine the relationship between heat and decaying plant matter in a compost pile. (S)


  • 2-3 earthworms
  • blue and red pencils or markers
  • gallon zip top bag (kit)
  • quart zip top bag (kit)
  • small trash bag


Ask your child what happens to a plant when it dies. Explain to your child that the plant goes into the earth and breaks apart. This process is called decomposition.