Performing the Mold Bread Experiment

Hypothesis

In the Mold Bread Experiment we are trying to prove that;

“Mold grows quicker at higher temperatures.”(Hypothesis)

What You Need for the Mold Bread Experiment

• 15 slices of bread. Any sort will do but it is perfectly fine to use cheap white sliced bread as then you will know that all of the slices are a similar size, weight and thickness. You must make a note of the brand and use-by date so that anybody else wanting to repeat the Mold Bread Experiment can use the same type.
• 15 sealable sandwich bags
• 1 piece of film or clear plastic with a 10x10cm grid drawn onto it
• Q-Tip
• Clean knife
• Chopping board
• Sticky labels
• Marker pen
• Mold Spores – if you can’t get these from your school don’t worry. There are mold spores all around us in the air which will eventually grow on the bread but your experiment will take longer.
• Mask
• Gloves

Method

1. Using the sticky labels and the marker pen label the bags. Mark 5 bags as ‘A’, 5 as ‘B’ and 5 as ‘C’. You also need to label each set of bags 1 to 5.
2. Cut the bread into 10 x 10 squares using the chopping board and knife.
3. Inoculate the bread thoroughly with the mold solution. Try to coat each slice with a similar amount of the culture although this can be difficult.
4. Put one slice of this bread into each bag and seal the bags tightly.
5. Put the 5 ‘A’ bags into the freezer, the 5 ‘B’ bags into the refrigerator and the 5 ‘C’ bags somewhere safe in a warm room. Because the bags in the freezer and fridge will not be getting much light it is best to cover the ‘C’ bags to make sure that light is a constant.
6. Every 24 hours, preferably at exactly the same time every day, using the plastic grid, count the number of square centimeters of mold on each slice of bread. If the mold covers more than half a square, count it as 1cm, if less than half a square, count as 0 cm. You must never open the bags.

7. You should repeat these counting processes for 10 days or until there are significant measurable results.
8. Keep a careful note of your results for each slice of bread for the entire duration of the experiment. You can even take pictures or draw the slices if you want to be really scientific!
9. Average the results for sample types A, B and C.
10. Once you have finished, throw out all of the bags without opening them.

Results

Because each square of bread is 100 cm2, you can express your results as a percentage. For each of the bread types, A, B or C average the amount of mold grown over the ten days and write these figures into a table.

You can then plot this information onto a graph and begin to explore your results. You can plot the amount of mold on each bread sample and compare it to the number of days, like in the diagram below. This can be done with a sheet of graph paper and colored pens or on a computer.