Moldy Playdough
Question:
Which ingredient (salt, sugar, cornstarch) will preserve homemade playdough the longest to prevent mold growth?
Will the temperature (incubator, room temp, refrigerator) that the playdough is stored at affect the rate of mold growth?
Will the temperature (incubator, room temp, refrigerator) that the playdough is stored at affect the rate of mold growth?
Hypothesis:
We predict that if we use salt as our preservative and store the playdough in the fridge the mold won't grow as quickly because salt is traditionally used as a preservative in food and cooler temperatures slow down mold growth.
Our Experiment
Materials:
Playdough salt/ cornstarch/ sugar flour water vegetable oil measuring cups and spoons mixing bowls Miscellaneous sterilized 4 ounce glass baby food jars ruler incubator fridge room temperature (kitchen counter) thermometer |
Safety ProceduresWhen sterilizing jars in boiling water use oven mitts and avoid splashing water.
When handling glass jars be careful not to break them. Be aware of any allergies; Do not eat or handle if allergic. |
Procedure:
1 sterilize glass baby food jars and set them aside 2a salt playdough mix 1/4 cup salt with 1/4 cup flour gradually add 1/4 cup water and 1/2 tbsp vegetable oil mix additional 1/4 cup flour in slowly 2b sugar playdough mix 1/4 cup sugar with 1/2 cup flour gradually add 1/4 cup water and 1/2 tbsp. vegetable oil mix additional 1/4 cup flour 2c cornstarch playdough mix 1/4 cup cornstarch with 1/4 cup flour gradually add 1/4 cup water and 1/2 tbsp vegetable oil mix additional 1 tbsp flour 3 knead dough to desired consistency 4 use ruler to measure 10 equal parts of playdough 5 place 1 playdough part into sterilized 4 ounce glass baby food jar 6 place jars into designated temperature ( room, fridge, incubator) with lid placed on loosely 7 monitor playdough for mold growth every 24 hours and record data for ten days |
Watch us in action:
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The Science Behind It
Salt works as a preservative by drying out foods. Salt absorbs water from foods making the food too dry to support mold growth. In addition, mold grows best at specific temperatures. Cooler temperatures slow down mold growth.
Results
Table 1 Days to Mold Growth-Room Temperature
Jar Salt Sugar Cornstarch
1. 2
2. 2
3. 2
4. 2
5. 2
6. 2
7. 2
8. 2
9. 2
10. 2
Summary Table 1: Playdough stored at room temperature with salt or sugar as the preservative had no mold growth by day 10. Playdough stored at room temperature with cornstarch as the preservative had mold growth by day 2.
Table 2 Days to Mold Growth-Fridge Temperature
Jar Salt Sugar Cornstarch
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Summary Table 2: Playdough stored at fridge temperature with salt, sugar or cornstarch as the preservative had no mold growth by day 10.
Table 3 Days to Mold Growth-Incubator
Jar Salt Sugar Cornstarch
1. 1
2. 2
3. 2
4. 2
5. 1
6. 1
7. 1
8. 1
9. 1
10. 1
Summary Table 3: Playdough stored at incubator temperature with salt or sugar as the preservative had no mold growth by day 10. Playdough stored at incubator temperature with cornstarch as the preservative had mold growth by day 1-2.
Conclusions
In conclusion, the cooler fridge temperature prevented mold growth in salt, sugar and cornstarch playdough by day ten. In the warmer incubator temperature the cornstarch playdough grew mold the earliest at day 1-2 compared to the room temperature cornstarch playdough which grew mold at day 2. Neither the salt or sugar playdough in the warm storage temperatures grew mold by day ten. Our hypothesis about the temperature variable was proven correct for the cornstarch playdough because it grew mold the best and fastest at the warmest storage temperature. Our hypothesis about the temperature variable for mold growth in the salt or sugar playdough was disproven as neither grew mold by day ten in any storage temperature.
In addition, playdough made with sugar or salt as the preservative did not grow mold by day ten. The playdough made with cornstarch as the preservative only grew mold in the warmer temperatures but did not grow mold in the cooler temperature. Our hypothesis about salt working as the best preservative to prevent mold growth was disproven because our playdough made with sugar as the preservative did not grow mold by day ten and our playdough made with cornstarch as the preservative did not grow mold by day ten at fridge temperature.
In summary, even though the playdough stored at fridge temperature regardless of the preservative used did not grow mold by day ten, the playdough was too hard to play with due to its firm texture. Also, the playdough stored at incubator temperature with salt or sugar as the preservative did not grow mold by day ten but the sugar playdough melts into a sticky mess and the salt playdough dries out with salt crystals coating the surface. The playdough stored at room temperature with salt or sugar as the preservative did not grow mold by day ten but the sugar playdough became as hard as a rock and the salt playdough remained the same consistency as the day it was made.
Our recommendation is to make playdough with salt as the preservative and store it at room temperature.
Kim
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Sofia |
Amelia |
