Ecosystem Change Investigation 5-1:

Decomposition In a Bag

Investigate the role of temperature in decomposition.

What You Need

• 12 zipper-locking plastic bags, or clear plastic soda bottles with lids

• thumbtack for making small holes in the bags or bottles

• heating pad

• several thermometers

• measuring cup and water

• 6 half-gallon milk cartons cut in half lengthwise to make trays

• several large paper grocery bags

• variety of organic items from each category below to put into the decomposition bags

• 1-2 cups of rich garden or forest soil to provide a variety of decomposers and scavengers (bacteria, fungi, earthworms, isopods)

Moist Items Dry Items
carrot uncooked beans
apple uncooked pasta
lettuce or spinach popped popcorn
natural bread unpopped popcorm
cooked pasta matzo cracker
grass clippings dead leaves

Getting Started

1. State your hypothesis about the effect of temperature on decomposition.

2. Outline an experiment to test your hypothesis. Sketch your setup.

3. List the factors that you will control in your experiment.

4. Monitor your experiment over a two-week period. Keep a daily log.

Describe Your Results and Conclusions

If Earth’s climate warms, what do you predict will happen to the rate of decomposition in the temperate forests of the world? How might this affect the level of CO2 in the atmosphere?