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1 class periods of 45 minutes each
The decomposition of grass clippings and leaves into compost demonstrates one of the useful functions of microorganisms.
This experiment will require about one month to complete. Plan accordingly. You may want to set up this activity at the outset of this unit and track its progress throughout the unit.
Nature has its own recyclers--microorganisms. When something dies, microorganisms use the dead matter as food so they can grow. This process is called decay. Leaves that fall to the ground begin to decay because of the actions of microorganisms in the soil. Rain provides the water that is needed to complete the chemical reactions. Fallen leaves turn dark and crumble because microorganisms are breaking down the larger chemicals in the leaves into simple materials that are released into the air and soil and can be used by other organisms.
In this experiment, the following changes will be observed:
Allow students to make their own decomposition chamber. Once students select their initial materials, have them predict which materials will decompose the most quickly and the nature of the final product. Put end products into a school garden plot.
Evaluate the answers to the questions in #7 that students recorded in their science journals.