Science Buddies: "Ask an Expert"

how to make bread last longer?
we made bread ourselves, we're testing the variables of temperature, whether it is under light or shaded, whether it is sealed or not.
one bread indoors,under light,sealed
one bread indoors,shaded,sealed
one bread indoors,under light,unsealed
one bread indoors,shaded,unsealed
one bread refrigerated,sealed
one bread refrigerated,unsealed
one bread on balcony,shaded,sealed
one bread on balcony,under light,sealed
one bread on balcony,shaded unsealed
one bread on balcony,under light,unsealed
then we're going to see how long it takes for each of these bread to mold and record the results. after which, we will research and add more other extra ingredients that we hypothesize will make bread last longer. then we will make another batch of the same type of bread, except they would then have extra ingredients. after placing the bread in their respective areas, we will wait for them to mold again, and if they all take longer to mold, our experiment would be a success. but to make it more like a highschool level project, we will also test the variables stated above, and see if temperature, light, and selaed or unsealed, would affect how long bread takes to mold.
would there be a better way to conduct this experiment? should there be more variables added? how do we make this more highschool level?please offer some suggestions =) thankyou

Hi,

This does seem like a very simple but important question in industry. Your setup looks fine, with appropriate variables. One thing you could do (in addition) would be to attempt to further culture the mold that grows on the bread to determine if the types of bread mold that grow under each condition are the same. For example, bread that is refrigerated but not sealed might grow a different type of mold than bread that is left outdoors and unsealed. If you continue to culture the mold that grows and find different types of mold (or different proportions of the same molds), you might be able to identify genetic differences that allow each one to survive under each condition.

Hope this helps!
Aaron Lin

Hi there,

What you are doing is called a factorial design. Here is one website to describe what that means (though you can Google others): http://www.socialresearchmethods.net/kb/expfact.php

One thing to keep in mind with this kind of experimental design is how you will analyze your results to look at the different factors.
In your case, you have three major factors you're investigating:
1) Temperature - indoors (room temp, controlled), refrigerator (cold temp, controlled), balcony (fluctuating temperature)
2) Lighting[/b - shaded vs. exposed to light
- For this one, you might consider how to reproduce this factor in the refrigerator. Perhaps you can cover some of the bread with paper towel to make your shaded treatment here.
3) Exposure - sealed vs. unsealed

When you get to the point of analyzing your data, you will need to be careful to try to separate the effects of each factor from the others. There may be interactions, which means that one factor influences the effects of another. The best way to look at these types of things is called ANalysis Of VAriance (ANOVA). Let us know if you need help with those statistics once you've collected your data!

Good luck,
Heather