6th Grade · Science · Activity · shared by Luke Morgan
Investigate forest decomposition and the mystery of vanishing wood chips, focusing on fungi's role in breaking down lignin. A 6th Grade Science activity.
For the past three months, the Martinez family has been tossing their kitchen scraps—apple cores, potato peels, and coffee grounds—into a wooden bin in their backyard. However, every time they check the bin, the pile never seems to get taller. In fact, large chunks of organic waste seem to vanish overnight, leaving behind only a crumbly, dark soil. Something in that bin is working hard, but what exactly is it?
Your Mission: You are a biological investigator. Use the evidence provided below to determine which organism is the primary "suspect" responsible for breaking down the toughest materials in the compost bin. Follow the three phases of investigation to solve the mystery.
Phase 1: The Evidence File
Read the following field notes and scientific data collected from the Martinez backyard. Use these facts to understand the conditions inside the compost bin.
Evidence Item
Details / Observations
Visual Inspection
The scraps are covered in tiny, thread-like white structures called hyphae. Some areas of the compost look pale and stringy.
The "Glue" Test
The bin contains woody stems and corn cobs. These are held together by lignin , a tough chemical "glue" that most animals cannot digest.
Chemical Reading
The bin has high levels of oxidation occurring. This chemical reaction uses oxygen to break strong chemical bonds.
Microscopic View
Tiny proteins called enzymes are being released into the wood scraps, dismantling them at a molecular level.
Phase 2: Suspect Profiles
Analyze these three common backyard organisms. Compare their "Skills" to the evidence found in the Martinez compost bin.
Suspect A: The Red Wiggler (Earthworm)
Method: Eats soft organic matter and turns it into nutrient-rich castings.