Friday Sprog Blogging: How Well Does Mold Form in Different Conditions? (A science fair project)

The science fair happened, and the younger Free-Ride offspring's project board is now home. (The teachers are still judging and grading the sixth grade projects, which means that the elder Free-Ride offspring's project board is still at school.)

Here, in pictures, are the highlights of the younger Free-Ride offspring's project:

A straightforward descriptive title. (The kid may have a future writing scientific journal articles.)

Gotta have hypotheses to test.

The equipment was not terribly fancy. Then again, except for the bread, it was stuff we already had on hand, which is a plus.

Maybe it's just me, but I always like it when science fair results depart from initial expectations. It makes it feel more like real science, I guess.

The science fair instructions from the school were emphatic that kids should not bring in potentially biohazardous specimens with their projects (and mold was among the things specifically mentioned in the "NO!" list), so the younger Free-Ride offspring took pictures. It may have been smelly, but the range of colors of mold that grew is actually kind of impressive.

My favorite part of the younger Free-Ride offspring's project is the data visualization. For each of the specimens that grew mold in each set of experimental conditions, the kid measured the mold spots (in square centimeters) and added up the total molded area on each data-collection day. Data was collected until each bread sample was totally molded over.

To generate these graphs, the younger Free-Ride offspring calculated the mean mold area for each given type of bread in a particular set of conditions on a particular day. Since each of the bread samples was 4 x 5 centimeters, the younger Free-Ride offspring drew a 4 x 5 rectangle to represent the bread sample and then plotted the average mold growth by filling in the appropriate number of squares. You can see as you go across the plots from left to right that ady by more and more squares get filled in until all 20 are filled, representing complete mold coverage.

10 responses so far

  • Dario Ringach says:

    I love the visualization which brings up an obvious question.

    Why did the mold always start to develop at the edges?

    Anway... What kind of science fair doesn't allow you to bring the science to school?!

  • Janne says:

    Does the PI sprog have any idea why the, well, rougher bread types develop mold faster than the smooth ones? I would have thought it would be the opposite, as whole-grain type breads would have less surface area and more dry, hard to digest bran and such.

  • reviewer #3 says:

    1) Ingredient lists for the types of bread should be included in the online supplementary data file, seeing as we do not know if *other* ingredients besides 'preservatives' were different between the types of breads. This is a serious issue, although using multiple breadtypes of each general variety (preservative containing and no preservatives) somewhat ameliorates this issue.

    2) How, exactly, did the bread get into the 'dark' and 'plastic' conditions? Was it removed from the bread package with (boiled) tongs and placed into untouched-by-human-hands fresh foil/plasticwrap? And I mean, really. From the material used, you can't exclude the possibility that those weird foil trays were innoculated with mold spores and your paper plates were clean. That is a serious limitation in the study!

    3) I also wonder if you had a way to have a continually "moist" condition (putting the bread in the bathroom?) if there would have been an effect of moisture.

    4) Also, it should be noted in the write-up that there is no "cold" condition, so much as a "cold and semi-dark" condition (unless the fridge lightbulb was rigged somehow).

    5) I am somewhat disappointed to read there was no "dark" and "moist" condition, as that is what I have been told is best for mold growth.

    6) I am also sad there is no shotgun sequencing to determine the range of species of mold, but that would kind of defeat the 'materials on hand' aspect, I suppose. Though it looks like that would yield some very interesting inter-bread differences.

  • physioprof says:

    That's some fucken nasty-asse molde!

  • captainahags says:

    Sounds like Dr. Free-Ride is raising a good little crop of scientists there =)

  • Isabel says:

    "It may have been smelly, but the range of colors of mold that grew is actually kind of impressive."

    Did you have a chance to look at them under the microscope or magnifying glass? Although identifying them might have been beyond the scope of this project, something about what they actually looked like under magnification would have been nice, as people generally don't know what type of organism mold is. Maybe under "future research" ;)

    I don't remember if I've seen your response to this question before, but, if you don't mind my asking, how much do you help your kids with their homework/science projects?

  • [...] the comments on the post about the younger Free-Ride offspring's science fair project, Isabel asks: I don't remember if I've seen your response to this question before, but, if you [...]

  • dryad says:

    Very well done report. Low light, moist, and cool conditions--sounds like a verifiable finding. I suppose the plastic wrap helps to trap moisture and that adds to the effect, maybe?

    I hope you all did some serious bleaching of the equipment afterward. One part bleach to 19 parts water is what we use in the Microbiology lab on our work benches.

  • briana boler says:

    I thik this i a grear science fair project

  • savannah says:

    wow!!!! thats a really good science fair project good idea!!

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