Science Buddies: "Ask an Expert"

I am getting ready for the science fair on August 8th. I am figuring out if different packages will effect the growth of mold on a banana over a period of 2-4 weeks. I have a paper bag, zip lock bag, and a Walmart fruit bag. I am getting ready to review my experiment, but I do not know how to find a control variable for my experiment. My teacher says I may be able teacher says I could use saran wrap, but he also says it may not work. Do you know if that could work, or would something else be better to use?

I also have a question about the variables that stay the same. I would keep the bananas the same weight, color, and size, and I would put them in the same room with the same amount of light, and at the same temperature. Although, I am not sure if the bag size should stay the same. Would that mess up the experiment? Or would it be okay if they were different sizes?

Hi whollis,

For your control, I would suggest using a banana that isn't in a bag. If you leave a banana out on a plate and put it in the same location as the rest of the bananas in bags, then you will be able to isolate the effect of putting the banana in a bag.

As far as the other variables go, it sounds like you have a pretty exhaustive list. Good for you! Getting bags that are similar sizes is a good idea, but I'm not sure you will be able to find bags that are all the exact same size. You wouldn't want to do the experiment with a snack-sized Ziploc bag, a 3 cubic yard paper bag, and a regular-sized Walmart bag. But, a gallon-sized Ziploc, lunch-sized paper bag, and regular Walmart bag are fairly close in size and would work well for this project.

Post back if you have other questions!