Does Degradable Plastic Really Degrade?
(Adapted from Recycled Alaska Activities Handbook,
Alaska Department of Environmental Conservation, Juneau, AK)
CONCEPT: Even goods which are biodegradable decompose at various rates.
OBJECTIVE: To see if plastic degrades and how fast different types degrade.
KEYWORDS: photodegradation, biodegradation
Cut two pieces from each type of plastic. Every piece should be approximately the same size. Collect several brands and thickness.
Note: Photodegradable means that the product is broken down by exposure to light. Corn starch biodegradable plastic is broken down by microorganisms, which actually eat the corn starch and leave the plastic behind.
1. Find a safe place outside the school that is not disturbed too much.
2. Take two pieces of scrap wood and attach one sample of each type of plastic to each board. Use a piece of nondegradable plastic as a control.
3. Place one set of samples outside where they will be exposed to the sun. The other set should be buried at least partially in soil so that the soil microoranisms will have a chance to carry out degradation.
4. It will take several months to see any changes so you may need to start your experiment in the beginning of the school year.
5. Check your samples once a month, and record any changes.


Corn Starch Degradable Plastic #1

Corn Starch Degradable Plastic #1 

Photo- Degradable Plastic #1 

Photo- Degradable Plastic #2  

Non- Degradable Plastic  












*Note: in Northern climates, you may not be able to observe samples year-round.
Discuss under what environmental conditions each type of plastic would decompose? Would they decompose in a landfill? Along the highway? In the ocean? (Plastics in the ocean pose a hazard to marine life.)