Have you ever seen something labeled "biodegradable" or "compostable" and wondered what that means? A lot of different products—such as food containers, bags, packaging materials, and disposable spoons and forks—claim to be biodegradable or compostable, meaning they will eventually decompose naturally. But these objects are often made of different materials. Do they decompose differently? If so, which decomposes the fastest? In this science activity you will make your own indoor composter and investigate how well different biodegradable and compostable items decompose in it.


Composting is a great way to recycle material that might otherwise be thrown into a landfill. The result of composting is very beneficial—you end up with decomposed materials that can be used to feed, or fertilize, plants. Compost is rich in nutrients that plants readily devour.
One material that cannot be composted and frequently finds its way into landfills is plastic. Many everyday items such as grocery bags, food containers, packaging materials and disposable forks and plates are made of plastic (usually polyethylene or polystyrene). Plastic is estimated to take hundreds of years to decompose. Consequently, researchers are developing new products that decompose more quickly and can be used instead of plastic products. Some of these products claim to be "compostable" or "biodegradable." Most compostable products are made from cornstarch (as a processed form, polylactic acid, or PLA), fibrous plant pulp (such as that from sugarcane, called bagasse) or starch from other plants, such as potatoes. Many biodegradable products are also made from other plant materials, such as sugarcane pulp or bamboo. New materials are being tested all the time to see if they can be transformed into biodegradable or compostable products.