Title: Bacteria in Ice?

Purpose: The purpose of this experiment is to determine whether or not the ice we put in our drinks is going to be more bacteria infested than the toilet water. I myself have seen them pour the ice into a five gallon bucket at Taco Bell then dump it right into the ice dispenser (Abby Wilkins). The danger zone for bacteria is around 40-120 degrees Fahrenheit. (Sullivan, 2006) However water does freeze at 32 degrees which is colder than 40 degrees so it wouldn’t even make sense for there to be bacteria in ice. In past experiments it has been proven that bacteria does grow faster and in larger amounts in warmer environments. (Brownlee, 2005) In order to calculate the growth of the bacteria and how fast it is growing we will need to use a growth calculator program. (Vasguez, 2006). We hope to achieve great results with this experiment. (will the shape of the ice matter-dara) (wouldnt dumpping ice into an ice disensper refreez the ice killing the bacteria?-doolan)

Hypothesis: If we take a sample of toilet water then it will grow more bacteria than the samples of ice collected from fast food restaurants.
Materials:
-ziploc baggies(3)
-sterile cotton swabs - masking tape - wax paper - centimeter ruler
- auger
- tray (1)
Procedure: 1) Get samples of ice from three fast food restaurants in your area (ex. Taco Bell, McDonalds, Michaels, etc.). 2) Label each of the Petri dishes with your sharpie each with the name of the place where they came from. 3) Then pour a thin layer of the gel you have prepared into the Petri dishes. 4)Take one of the sterile cotton swabs and dip it into one of the three melted ice samples that your have collected. 5) Repeat step four with the other two ice samples you have previously gathered. 6) Take one of the cotton swabs and swab the toilet water then swipe the swab all over the gel inside of the Petri dishes. 7) Then tape each of the dishes’ lids to their bottoms with masking tape. 8)Next take the sheet of wax paper and trace four circles the same size as the Petri dishes. 9) Set up a grid of lines spaced exactly one centimeter apart, the lines should go both horizontal and vertical. 10) Place each of the dishes onto a tray, then wait approximately one week in order for the bacteria to grow. 11) Once you have waited the allotted time you should place the wax paper over the top of the bottom of the Petri dish and trace the spots of bacteria growth with the sharpie. 12) Total up all of the boxes you have colored in and create a percentage by dividing the number of boxes filled with bacteria by the number of boxes on the grid you started out with.
Data:


Analysis: According to the results shown in my graph the sample from Michaels grew the largest amount of bacteria and had the least amount of clean space. The bathroom however has grown the least amount of bacteria and is almost fully clean. Taco Bell is the fast food restaurant that shows the least amount of bacteria grown.Conclusion: We have rejected our original hypothesis. Our first hypothesis was that if we take a sample of toilet water then it would grow more bacteria than the samples of ice collected from fast food restaurants. However our results showed the opposite because the toilet water sample grew the least amount of bacteria. Contrary to our hypothesis the toilet water from the bathroom ended up with the least amount of bacteria grown, the amount was less than every single one of the fast food restaurants we have tested. Limitations: When we placed each of the Petri dishes onto the tray the ones on the outer edges could have been exposed to more heat than the others. We could have stacked the Petri dishes and then rotate them every other day. The amount of the gel in the bottom of the dishes could have differed and then provided a different environment for each sample of the ice to grow on. We could have measured and been more careful about the amount of gel. Our new and improved hypothesis is, if we take samples of ice from a few fast food restaurants then they will grow larger amounts of bacteria than toilet water.
Conclusion: We have rejected our original hypothesis. Our first hypothesis was that if we take a sample of toilet water then it would grow more bacteria than the samples of ice collected from fast food restaurants. However our results showed the opposite because the toilet water sample grew the least amount of bacteria. Contrary to our hypothesis the toilet water from the bathroom ended up with the least amount of bacteria grown, the amount was less than every single one of the fast food restaurants we have tested.
Limitations: When we placed each of the Petri dishes onto the tray the ones on the outer edges could have been exposed to more heat than the others. We could have stacked the Petri dishes and then rotate them every other day. The amount of the gel in the bottom of the dishes could have differed and then provided a different environment for each sample of the ice to grow on. We could have measured and been more careful about the amount of gel. Our new and improved hypothesis is, if we take samples of ice from a few fast food restaurants then they will grow larger amounts of bacteria than toilet water.






Works Cited
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