A drink of Bacteria
Audrey Hao
University Hill (Secondary)
Floor Location : M 197 H

You reach for a glass of water that you left on the counter-top this morning, and drink it thinking that it's perfectly safe-because hey, why would there be potentially dangerous organisms in an isolated cup in my clean abode?rnrnAs an individual with a relatively weak immune system that is often the victim of colds and stomach infections, I am very curious about how to protect myself.rnrnMy experiment is to determine the different amounts of bacteria present in a glass of water covered vs a glass uncovered. The reason I only used water in my experiment is because we do not refrigerate our water to prevent spoilage like milk and juice, and pop drinks are usually consumed right away before they lose their fizz.rn To determine the exact amount of colonies I used a method of distillation to count the amount of colonies of a 0.001% distillation and multiplying the amount by 1000 to determine the amount most likely present in my un-distilled sample.rnrnFirstly, I swabbed each cup (covered and uncovered) at the start of the experiment and loaded the swabs onto agar plates, giving the bacteria a week to grow, taking note of the patterns in growth every 12 hours.rnrnThen, after the samples are left for 12 hours they are swabbed again and put onto fresh agar.rnrnFinally, after another 12 hours they are swabbed again using a fresh sample started at the same time as experiment for a final time and put onto fresh agar again.rnrnThe growth rate of each plate is compared by rna) how fast the bacteria dividernb) the total amount of bacteria at the end of the week.rnrnConclusion: There is a positive correlation with glasses of water left out and bacteria amount, and the amount of time left out before it was swabbed. rnThe speed/rate in which the bacteria divide did not change in all cases, and the glasses with covered water had little to no bacterial growth on the agar (the small amounts of bacteria is most likely due to contamination errors).rnrnThis experiment has shown me never to leave something even as innocuous-looking as a glass of water out to the air, as that is potentially drinking up bacteria that could be carrying a pathogenic illness. It also shows how simple measures such as saran wrap can help you tremendously in the case if someone around you is sick.rnrnA thought that I have as I complete this experiment- are the drinks usually set up in schools after a sports events and other events where many people congregate safe from bacteria? rnIf bacteria are able to infect water, how about viruses? Can colds also be transmitted through neglected water left in the open?rnrn I presume from my conclusion that lids and wraps are very important not only in drinking water, but bacteria may also be present in places such as eye drops if also left out in the open.