When I was relaxing on a beach in Sicily, Italy, I was impressed by a group of students who were going around talking to the beach-goers. They wanted to raise awareness of the impact of rubbish being left on the beach. This was a potential nesting area for turtles. One of the pieces of information they were sharing was the time it took for different materials to biodegrade. Unfortunately I didn't take a photo of their information but it provides an opportunity for a longer term study. Some of the most interesting facts related to the different times it took for biodegradable materials to degrade. I've also seen this activity done with other materials but I think the biodegradable option seems interesting.
Take at least 5 different organic materials and bury them in your compost bin or 10 cm under the soil.
If you have external use data loggers, you could track the temperature change in the area of the objects.
Try for example:
- apple core
- banana skin
- orange peel
- bread crust
Measure the mass before and after.
Make qualitative notes on the composition.
I don't know how long this takes and it must depend on your local climate.
Try leaving them for two weeks.
IA Tip: An extension of this might be with biodegradable plastic bags. I have read that some truly biodegrade but others just degrade into smaller pieces of plastic faster.