Lesson 11: Decomposition Detectives

Timing: Year Round

Objective: To help students learn about natural life cycles and environmental processes. Also to help students learn about the human impact on our ecosystems (biodegradable vs. non-biodegradable materials). Students will explain what decomposition is and why it’s important to ecosystems and will observe the decomposition process over time.

SMART Learning Goals:

• K-2nd Grade: Students will bury two items (one natural, one plastic) and check them weekly, drawing what they look like after 4 weeks.
• 3rd - 5th Grade: Students will record decomposition changes for 4-6 weeks and write a comparison of which materials decomposed and why, including photos or drawings.

Materials:

• Small shovels
• 3-5 small organic items, such as: banana peel, leaf, piece of bread
• 1–2 non-biodegradable items, such as: a small piece of plastic wrap, aluminum foil, paper straw, a plastic water bottle (disposable).
• Mesh produce bags or biodegradable planting bags (a way to store samples for easy retrieval)
• Wooden plant markers or flags (to label sites)
• String or tape measures
• Clipboards, pencils, and science journals
• Optional: moisture meter, pH strips (for older students)

Activities:

Begin with a class discussion: Ask: What happens to things when they “disappear” in nature?

Explain the idea of decomposition.

• Some living things are “decomposers,” such as fungi, bacteria, earthworms
• Some things are biodegradable and some are non-biodegradable.
• Discuss why decomposition is important.

Set Up

• Choose a spot in your outdoor lab for this activity.
• Mark spots for students to bury things in advance: Mark plots in advance (sun vs. shade, dry vs. moist, grassy vs. bare soil).
• Have a selection of materials and ask students to predict which will decompose first, completely, not at all, etc.
• Bury the materials. Be sure to mark their positions.

Observe and Record

• Visit every few days. Have the students very carefully pull up the mesh bags to observe what is changing. Then, carefully rebury them.
• After 4-6 weeks, dig up the bags one final time to make last observations. Put the items side-by-side.

Discuss

• Ask students questions like: Which materials decomposed most? Did any not change at all? What environmental conditions affected decomposition? Were our hypotheses supported by evidence?

Reflection

• Students should use their science journals to draw or write about decomposition.

How this activity supports Common Core Science Standards

K–2:

• K-ESS3-3: Communicate solutions that will reduce the impact of humans on the land, water, air, and/or other living things in the local environment.

3–5:

• 5-LS2-1: Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.

Related Lessons:

• Lesson 1: Introduction
• Lesson 2: Living vs Non-Living Things
• Lesson 3: Soil Discovery and Decomposers
• Lesson 4: Plant Growth
• Lesson 5: Wind Direction and Study
• Lesson 6: Pollinator Patrol
• Lesson 7: Butterfly Garden
• Lesson 8: Seed Dispersal
• Lesson 9: Solar Energy Exploration
• Lesson 10: Microhabitat Study
• Lesson 12: Building a Scale Model of the Solar System

Lesson 11 - How to Build and Teach From Outdoor Science Learning Labs.pdf