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INT1 Task 3
Does the Cold Stop Bread Mold?
By James Thompson
Project Plan Design
Bread mold fungus is the most common fungi in the world. Molds occur commonly on bread due
to the desirable source of nutrients for the mold. In tandem with the nutrients, bread is typically
kept in warm and moist places where mold can thrive. (Mold 2015) Typically mold spores tend
to become active at temperatures between 70 – 90 degrees Fahrenheit. However, the spores
become dormant when introduced to temperatures below 32 degrees Fahrenheit. (Wold &
There are many different ways to see how mold spores thrive. Since it is such a common type of
mold, there have been many experiments done on bread mold.
Aldo-Rafael Cos carried out an experiment on four types of bread, each sealed in a Tupperware
container and moistened with a few drops of water. Each container was kept at room temperature
with an adequate source of light. The bread was observed for two weeks, with photographs of the
progression of mold being taken. The bread developed mold, though some slices developed mold
spots faster than others. (Cos 2005)
Sylvia Cini took a different approach to her experiment. While she followed the steps of the
experiment above, she took it a step further. She placed her containers in different temperatures
and varying degrees of humidity. Recording the results of her experiment. (Cini, 2015)
For this experiment, for ten days, each sample will be put into varying degrees of temperature,
moisture, and light. At the end of ten days the samples will be collected, photographed and
1. Clean and sterilize four Tupperware bowls. (Hand wash and 1 dishwasher cycle with
2. Make labels for Tupperware lids. (Sample and Temp should be noted on the labels).
3. Select four pieces of white bread. (Store bought).
4. Check bowls, make certain they are clean and dry.
5. Place the bread in the Tupperware bowls. (One slice to each bowl)
6. Prepare Sample B with a few droplets of water.
7. Place labels on lids:
a. One labeled “Warm and Dry” (Control)
b. One labeled “Warm Dark and Dry” (Sample A)
c. One labeled “Warm and Moist” (Sample B)
d. One labeled “Cool and dry” (Sample C)
8. Seal samples.
To adequately test each environment for their ability to excite or render mold spores dormant, the
experiment needed to have multiple samples in varying degrees of temperature and light. It also
required a sturdy container to protect the validity of the sample.
Sequence of Events
The amount of mold grown on the samples is dependent on the temperature of the environment
they are placed in and any moisture present.
1. All temperatures in temperature control areas have been confirmed by use of the
2. Samples are then placed in the temperature controlled areas:
a. Control 70 Degrees Fahrenheit
b. Sample A 80 Degrees Fahrenheit
c. Sample B 70 Degrees Fahrenheit
d. Sample C 30 Degrees Fahrenheit
3. Samples are checked every day, for ten days, at the same time each day.
4. At the end of ten days, the samples are collected, measured and photographed.
5. All samples will be properly disposed in a sealed plastic bag.
6. Containers will be thoroughly cleaned. If unable to clean, they will be disposed of.
Tools and Technologies
White Duct Tape (Labels)
4 Tupperware containers
4 slices white bread
Kitchen thermometer (Degrees Fahrenheit)
Refrigerator (Set to 30 Degrees Fahrenheit)
Kitchen (Consistent temp. 70 Degrees Fahrenheit)
Water heater room (Consistent temp 80 Degrees Fahrenheit)
Iphone 5c camera
Microsoft Office Publisher
Independent variable: The Temperature the samples were exposed to during the experiment, the
amount of light each sample received.
Dependent variable: The amount of mold grown on each sample after a ten day period of
Controlled variable: The type of bread used, the size of the bread in the sample, the size of the
containers they were placed in, time the bread was checked everyday.
Threat to Internal Validity
By ensuring all of the Tupperware containers were thoroughly cleaned, sterilized and dried. The
experiment assures that no outside contaminants will interfere with the integrity of the samples
or the results. By ensuring all environments maintain a consistent temperature for the duration.
Labeling and sealing all containers before the experiment began.
The Hypothesis of this experiment is that bread mold will lie dormant in temperatures below 32
degrees and thrive in warmer temperatures. This hypothesis was based off of a statement made
on the Mold Blogger website.
Process of Data Collection
As predicted, mold spores are dormant in cooler temperatures. The samples in the warmer
temperatures experienced prodigious mold
growth, while the sample in cooler temperatures
experienced little to no growth.
This is the Control Sample. Note the light
coloration of the mold and its spread into the
crust of the bread.
This is Sample A “Warm, Dry and Dark”. 80
Degrees. Note the nearly complete
consumption of the bread by the mold, and the
growth of the white mold on top of the green.
This was the most remarkable growth in the
This is Sample B “Warm and Dry” 70
Degrees. Note the difference between Sample
B and the Control Sample, both kept at the
same temperature. This bread was slightly
moistened, very little mold is growing on the
This is Sample C “Cool and Dry” 30
Degrees. In contrast to the other samples in
the experiment, note the small amount of
mold on this sample. It would appear that
while the mold spores are dormant in cooler
temperatures, they do exhibit a small amount
When samples were collected and photographed, the data was entered into Microsoft Publisher
and a grid was imposed over each sample. The grid was to calculate the square centimeters of the
mold grown on each sample. The amount of mold grown on the samples in ten days seems a
good amount of time to let mold spores gather together. A longer time might be necessary,
though, to see if mold spores would remain as dormant as they were in cooler temperatures, or if
they would continue to grow.
The Above chart shows a difference of two cm² between the Control Sample and Sample B, and
a large difference of 37 cm² between Sample A and Sample C. Providing an average of 36 cm²
Confirmation of Hypothesis
The results shown above confirm that mold does lie dormant in cooler temperatures. While
keeping other samples at varying temperatures produced mold growth, keeping one sample at a
cooler temperature slowed the activity of the mold spores to a relative stand still. Only producing
a 2 cm² spot on the sample kept cool, as compared to the average 36 cm² on the other samples.
Experimental Design as a Key Factor
Designing the experiment is like a road map for the experiment. If something happens within the
experiment that was not in the original parameters, then one is able to check their map and see
where the error is. Similarly, if no error occurs, the design can map out a way to replicate the
successful experiment in the future
In order to replicate this experiment, it is important to use clean containers to store the bread in.
Since any outside material might contaminate the ability for the mold to grow. Take into account
that high humidity in certain regions might alter certain aspects of the experiment, causing
certain molds to grow faster.
Evaluation of Validity
If others were to use this experiment, it would help determine the validity of the steps used and
the results gathered. Scientists replicate experiments to determine if the original experiment was
successful. If the replication of the experiment is successful, the validity of the original
experiment is strengthened and the validity made firmer. If the experiment is not successful, it
provides a reason to reexamine the Experiment’s Design. To see if there is an unknown element
at play that the scientist was previously unaware of.
Mold (2015) Moldon Bread.Retrievedfrom: http://www.moldbacteriafacts.com/what-is-mold/mold-
Wold& Reeves(2015) Mold Blogger:FightMoldand Win.:3 ThingsMoldNeeds.Retrievedfrom:
Cos (2005) Comparingthe Rate of Mold Growth onDifferentBreads.Retrievedfrom:
Cini (2015) Three Cool Science ExperimentswithBreadMold.Retrievedfrom:
Meta (2015) Bar graphbuiltbythe Authorfromtestdata at: