Science Buddies: "Ask an Expert"

I’m working on a science project where I have to create a compost bin to test the decomposition rate of biodegradable materials. I was wondering if I could add the compost materials (as in the green and brown materials) at different times. Or if I have to collect all of them and then add them altogether. For reference I have to fill up a ten gallon bin. If needed I can provide the name of the project as well. I just wasn’t sure if adding the materials at separate times would mess with the results at all, please let me know!

Hello,
This sounds like a great project! I would suggest adding the materials together, if possible, as this will make it easier to calculate the decomposition rate. If you add them bit by bit, it could affect the decomposition rate, as the newer material will mix with the partially decomposed material. If you add new material at a constant rate, however, you can account for this process to still calculate the decomposition rate. This will definitely be a more complex process though.
Hope this helps!