Last updated: December 30, 2020
Lesson Plan
Life in a Log
- Grade Level:
- Upper Elementary: Third Grade through Fifth Grade
- Subject:
- Science
- Lesson Duration:
- 60 Minutes
- Additional Standards:
- NGSS 5-LS2-1. Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.
Essential Question
What survives on a decomposing log? Why can life survive on a rotting log?
Objective
The students will investigate decomposers in a rotting log, and discover some of the organisms living there.
Background
They may be dead, but downed trees still help their neighbors. A nurse log is a fallen tree that encourages new growth as they decompose, offering seedlings shade, nutrients, water and protection from disease and pathogens.
Preparation
Materials:
- Table knives, craft sticks, chopsticks, spoons, tweezers, etc.
- Large jar with perforated lid (preferably plastic)
- Magnifying lenses
- Insect identification guide (helpful to teacher)
- Flashlight(s)
Procedure
-
Bring sections of a partially decayed log into classroom in clear plastic bags.
-
Distribute students around the sections in groups. Carefully pull apart portions of the log, using the tools. Keep interesting items in the jar for later observation.
-
Have students observe the log at various depths- top, middle and bottom.
-
Identify the insects and other items using the guides. Ask students: What kinds of organisms did you find? What were the differences at different depths? Why was it different at different depths?
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Chart the students' observations and discoveries.
-
Sing (and perhaps march to) the "Decomposing March - sung to the familiar "count-off" chant used in the army. It is an excellent device for remembering the steps in decomposition, and teachers might like to teach it to the class during science or music lessons. It is a "march along" and does not need any music.
What can make a healthy tree
Into a dead one like we see?
Lightning...
Wildfire...
Windstorms...
Insects...
That's de-com-pos-ing...part one!Once the tree is on the ground
Decomposers break it down.
Fungi...
Moisture...
Bacteria...
Earthworms...
That's de-com-pos-ing...part two!De-com-po-sers leave behind
Nu-tri-ents of every kind.
They make...
Good soil...
They make...
Rich soil...
That's de-com-pos-ing...part three!In that so-il now we know
Brand new trees can start to grow.
From the...
Old tree...
Comes a...
New tree...
That's de-com-pos-ing...part four!
Assessment Materials
Have students draw and color the log section and organisms they observed.