Shopping for Bugs! Presented by The 7 th Grade of St. George School

Introduction Purpose- to find out how many colonies of bacteria grow on shopping carts. Purpose- to find out how many colonies of bacteria grow on shopping carts. We picked this experiment because we thought it would be the best way to help people out. We picked this experiment because we thought it would be the best way to help people out. Our hypothesis is that shopping carts are very dirty because a lot of people touch them. Based on reports, shopping carts are not cleaned and sterilized enough. Our hypothesis is that shopping carts are very dirty because a lot of people touch them. Based on reports, shopping carts are not cleaned and sterilized enough.

Materials The picture represents everything that we used to perform our experiment. We also used gloves during the experiment.

Methods Swab carts at different supermarkets. Swab carts at different supermarkets. Allow time to grow in media. Allow time to grow in media. Plate the samples. Plate the samples. Write down data. Write down data.

Results

Discussion Our hypothesis was that by plating the sample we could find which supermarket had the dirtiest shopping carts. Our hypothesis was that by plating the sample we could find which supermarket had the dirtiest shopping carts. The dirtiest supermarket had the most colonies on its plate. The dirtiest supermarket had the most colonies on its plate. We found that supermarket C was the dirtiest. (Due to low prices) We found that supermarket C was the dirtiest. (Due to low prices)

Strengths and Weaknesses Weaknesses Weaknesses Only one cart was tested per store.Only one cart was tested per store. We didn’t know how long the carts were inside or outside.We didn’t know how long the carts were inside or outside. We swabbed the carts that were inside.We swabbed the carts that were inside. Strengths Strengths We took our time to make sure that we performed the procedure correctly.We took our time to make sure that we performed the procedure correctly. We made sure that all of our tools were sterilized.We made sure that all of our tools were sterilized. We made sure that all the plates were treated equally.We made sure that all the plates were treated equally. The negative control didn’t grow any bacteria.The negative control didn’t grow any bacteria.

Conclusion Our conclusion is that supermarket C is the dirtiest out of all three. Our conclusion is that supermarket C is the dirtiest out of all three. Supermarket B is the cleanest out of all three. Supermarket B is the cleanest out of all three. Supermarket A is neither the cleanest nor dirtiest. Supermarket A is neither the cleanest nor dirtiest.

The End A special thanks to Mrs.Catuncan Mr. Luu and and TEAM SCIENCE.