Plastic bags, often made from oil-based polymers, are not widely recycled. This has sparked material engineers to invent commercially available bioplastics, made from natural polymer materials such as starch, which are compostable and degradable, but do these claims stack up?
30 minutes to set up
(days for results to show)
This activity develops student knowledge about materials and decomposition. It will also help to build the skills of a scientist, by observing change over time.
Some people are saying that bioplastics can be a more environmentally friendly alternative to oil-based plastics, but do these claims stack up? In this activity, you will replicate research conducted by University of Plymouth researchers into how different types of plastic, both bioplastic and oil-based, degrade .
You will need to select a variety of different materials and devise tests to see how these may decompose under different conditions.
Although we have suggested using three different materials in the activity, you can experiment with a range of different products that you think may make good alternatives to oil-based plastic.
Why not watch the video about this research before starting the activity in the Find out more section?
As you record observations about how the different samples change over time, think about the following questions:
Young people are likely to predict that the potato (natural polymer made of starch) will biodegrade more easily than the conventional plastic bag (man-made polymer made from hydrocarbons derived from oil), with bioplastic (if used) somewhere in between. Older children may notice that by adjusting availability of microbes, oxygen, or changing the temperature, they can increase the appearance of decay in the potato.
Teach this as a full science lesson for ages 11 to 14, using What happens to plastic when you throw it away? from Ocean Plastics Science | Ages 11-14.
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Science | Ages 11-14
Ocean Plastics Science ages 11-14 unit is a KS3 teacher resource combining both biology and chemistry. Students discover the journey plastic takes from manufacture, use, and disposal into the ocean. Included are teacher resources that allow students to emulate real research conducted by The University of Plymouth.