- Watching
Waste Rot
- Adapted From Composting:
Wastes to Resources, Cornell Waste Management Institute
-
- Back to Trash Goes To School
- GRADE LEVELS:
7-8
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- SUBJECT AREAS:
science
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- CONCEPT:
What types of materials decompose, and at what speeds?
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- OBJECTIVE:
To observe biodegradation, noting differences in degradability
of various types of wastes.
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- MATERIALS:
- handout: Watching
Waste Rot: Record
wide-mouth jars
compost sample
organic wastes (you may use one of several kinds of wastes)
flower pots
labels for jars and pots
record sheet
pencil
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- KEYWORDS:
biodegradable, decomposition
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- BACKGROUND:
The organisms in a compost pile need air. When there is not
enough air, the organisms die. New organisms that can survive
without air come into the compost pile. These new organisms produce
a gas that has a nasty smell.
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- The organisms in a compost pile also
need to be able to get at all the wastes to break them down.
Is it easier for the organisms to get at large pieces of wastes
or small pieces?
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- Let's investigate how long it takes
to break down wastes in the presence and absence of air. Let's
also see how long it takes to break down wastes of different
sizes.
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- PROCEDURE:
- Fill two wide-mouth jars half-full
with compost (contact Cooperative Extension or garden clubs to
get compost). Place equal amounts of a particular waste in each
jar. Then fill the rest of both jars with compost, burying the
waste. Fill the first jar with water and place a lid on the jar.
Add just enough water to the second jar so the compost is damp
but not wet to the touch. Leave the second jar exposed to air.
(Check on the second jar every few days to make sure the compost
is still moist, but do not overwater.)
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- Repeat the procedure with other wastes.
Label each jar with the name of the waste placed in it.
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- Take two more equal portions of a particular
waste. Cut the first portion into small pieces, Leave the second
portion uncut. Fill two flower pots half full with compost. Place
the cut-up waste in the first pot and the uncut waste in the
second pot. Cover the waste with compost, filling the pots. Add
water to the pots so that the compost is damp but not wet to
the touch. Check your pots every few days to be sure they are
still moist, but do not overwater.
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- Check your waste after two weeks. Which
wastes are decomposing? Record your observations.
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- Watching Waste Rot: Record
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- Name: _________________________________
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- Date: _________________ Date experiment
started: _______________
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- Fill in the following table. Under
"Waste", write the name of the item that you buried
in the jar or pot. Under "Compost", describe the condition
of the item buried in the compost. Include such things as how
decomposed the item looks, what color it is, and whether or not
you see fungi (spots or thin strands) on it.
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| Waste |
Exposed to Air (Y or N) |
Compost |
| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
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| Waste |
Cut/Uncut |
Compost |
| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
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- Did items decompose faster in the jar
with air or the jar with water?
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- Was there a smell coming from either
jar? If yes, what caused the smell?
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- Were items more decomposed when they
were cut up or uncut? Why?
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