Science Buddies: "Ask an Expert"

Hi, I need some advice on my experiment.
My question is "'what effect does temperature have on the ripening process of a banana?"
My hypothesis is "Higher temperature will allow bananas to ripen faster."

For my experiment, I was thinking about getting 12 bananas from the same store. Then I would place one banana in the fridge, one banana in room temperature and a third banana in a place with a higher temperature. I would leave it for three days and check the progress each day at 12 pm and record the process by taking a picture and describing the colour and texture. But is me determining the stage of ripeness by describing the colour and texture valid?

I think my independent variable is the temperature, the dependent variable is the time it takes for the banana to ripen and the control group is the banana left at room temperature to ripen normally. I am thinking about measuring the temperature of the locations by using a thermometer so I think my constant variables are the thermometer, the type of bananas, and the bananas not being near other fruit or vegetables. But I don't know if my experiment can be done because when buying the bananas I don't if they are at the same stage of the ripening process, and it would not give fair results. I also don't know how I can increase the temperature where I can put the third banana in. I am leaving the bananas in the same spot for three days so the temperature needs to be consistent and I'm not sure where I might be able to put it, maybe something like a thermal box?. I would really appreciate some help. Thank you

Hi Katarina,

You have a really thought out your experiment to great detail, which is a great first step
You are correct about your dependent and independent variables and yes, not keeping them near other fruits/vegetables is the best way to go about it!
Regarding the questions that came up in your mind as you planned the experiment, here are some pointers:

1. You can't really have full control over how ripe your bananas are at the starting point. However you can buy a single bunch and carefully remove individual ones without breaking the skin anywhere. Coming from the same bunch (make sure to buy a bunch where they all are firm and of uniform color) has the best chances of them being really comparable in ripeness at the start.

2. Regarding the higher temperature that you need in your third condition, one idea is to find a 'hotspot' in the house. Example: Often the top surface of a refrigerator is quite warm. If your school lab has an incubator (30 degree C or 37 degree C) to keep bacteria/yeast agar plates, that would be a better place for a more consistent temperature.

Two additional things to keep in mind:
a. It will be nice if you put more than one banana at each temperature (2-3 per temperature is enough). That way you have something to fall back on if something happens to one of your samples. You could also have multiple data points on your graph, which is nice too.
b. Putting a banana in a fridge will make its skin turn black although it will ripen slowly and stay firm longer. So taking photos of appearance could be misleading in this case, as a blackened skin will seem to incorrectly indicate that it is over ripe.

Let me know if you have more questions. Good luck with your experiment!
MS