Science Buddies: "Ask an Expert"

Hi I am a ninth grade student and I was just wondering how you would measure bread mold. I want to have a number that i measure and not just count how many days it takes for the mold to start growing. Please get back to me as soon as you can. Thanks!
Madison Keller

Hi Madison,

It's great that you want to really quantify the amount of bread mold you have, and not just qualitatively determine whether it is there or not. The easiest way to do this would probably be to calculate the area of the mold. One common method is to get (or make) a transparent grid (you could carefully, with a ruler, draw a grid on a transparency). Then you can overlay the grid on your bread pieces and count how many squares are "mold-filled." A similar option would be to take pictures of the bread and overlay your grid on the pictures. The benefit of this is that you don't disturb the actual mold, so you could make multiple measurements on the same piece of bread (i.e. one measurement per day) and get a growth curve over time.

Hope this helps! Feel free to post with any more questions.

JMP

What is transparent paper? I just want to make sure I am doing my project right and not get points off.

You can use anything that is relatively see through. One option would be transparency, like a teacher may have used for you on an overhead (although you may be too young to have used those). You may be able to get a couple of those sheets from your teacher, and if not, I believe they are available at office stores like Office Depot or Stables. Another option is tracing paper. A google search for "transparent grid" should give you some instructions on making them or possibly buying something usable.

Hello there,

JMP gave you some really good suggestions! You can purchase overhead transparencies at stationery stores such as Office Max, etc, although they could be a little expensive. If you want to go for something cheaper, I think plastic sheet protectors (http://image.made-in-china.com/2f0j00OC ... L-020-.jpg) may work just as well.

Let us know if you have anymore questions!

Connie