Which Bathroom is the cleanest? Katrina Sennett 4/23/10

Abstract Which Bathroom is the Cleanest? The purpose of this experiment was to find out whether my bathroom at home, the bathroom at Friendlys, or the McDonalds bathroom was cleanest.I ordered petri dishes and agar online. After preparing the petri dishes with the nutrition agar, I swabbed bacteria samples from each bathroom. I hypothesized that my bathroom would be the cleanest of the three. At first, I thought I was wrong and Friendlys had been the cleanest, for there was the least bacteria growing in the Friendlys petri dish. However, my bathroom at home ended up being the most bacteria-free, after watching and observing the dishes for several days. I hypothesized correct and my personal bathroom was the cleanest.

Planning Procedure 1.Gather Materials. 2.Prepare 6 Petri dishes with agar. 3.Roll the cotton swabs onto each toilet seat of McDonalds, Friendlys, and your bathroom at home (2 cotton swabs for each restroom). 4. Swab each cotton swab onto the agar in the 6 separate Petri dishes. 5.Store the Petri dishes into a cool and dark place 6.Examine the growth of the bacteria.

Planning Continued Materials Bag of agar Water Measuring cup 6 petri dishes 6 cotton swabs Something that can be used for stirring, such as a spoon

Data McDonalds had the dirtiest bathrooms. Chunks and colonies of bacteria were all around the agar. A different kind of bacteria formed in the McDonalds petri dish than in the other dishes. It was small and redish in color. Friendlys bathrooms were the second cleanest. There were a lot of small colonies of bacteria in the Friendlys petri dish, but not as much as McDonalds. One of the Friendlys petri dish wasnt clear as the other ones. It was slightly foggy. In one of the petri dishes from my bathroom the bacteria formed one big colony. The other petri dish from my bathroom had little bacteria growth. My personal bathroom was the cleanest.

Conclusion I hypothesized my bathroom would be cleanest. My Hypothesis was correct. The order of bathrooms from cleanest to dirtiest was Home, Friendlys, and McDonalds. During this experiment Ive learned… My personal bathroom is the cleanest of it, McDonalds, and Friendlys. McDonalds is a very filthy bathroom! Ive learned how to make agar using the agar powder. How to use petri dishes.

Sources Bennett, Kathrine. "California State Science Fair 2007 Project Summary." California State Science Fair. 30 April

Acknowledgements Id like to thank my parents for taking me around to get samples, buying and ordering the bacteria growing kit, and assisting me with my display board.