Discover Composting Organisms
(Adapted from Composting: Wastes to Resources, Cornell Waste Management Institute)



CONCEPT: What makes composting work?

OBJECTIVE: To expose students to some of the organisms that carry out decomposition.

MATERIALS: fresh sample of compost, glass slide or petri dish, hand lens or microscope, paper, pencil

KEYWORDS: bacteria, fungi, decompose

BACKGROUND: The insects, worms, bacteria, and fungi found in your compost pile do the work of making compost. You can see some soil animals with the naked eye, and for some you will need a hand lens or microscope. These organisms are some of the decomposers that fit into the cycle of life.

Cycle of Life
Producers (Grass)
Primary Consumers (Sheep)
Secondary Consumers (Wolf)
Decomposers (Insects, Fungi)

PROCEDURE: Put a small compost sample on a glass slide with a drop of water. Observe the sample under a hand lens or microscope. If you don't see live organisms, take a fresh sample from the compost. Draw pictures of what you see.

Option: Try to identify organisms with a field guide.

FOLLOW-UP: Take a field trip to see a compost pile, and bring a hand lens to do on-site investigations.

Discuss what would happen in the world if there were no decomposers. What would happen to leaves in the fall, or to dead trees in the forest? (Decomposers are the recyclers of the natural world. They break down organic matter and turn it into materials that can once again be used to support life. That is why compost contains many nutrients that help plants to grow. Without decomposers, we would all be buried in wastes!

Back to Solid Waste Activities Grades K-3

Cornell Waste Management Institute ©1991
Department of Crop and Soil Sciences
Bradfield Hall, Cornell University
Ithaca, NY 14853