Microwaving E-Coli!
Joyce Qi
Mulgrave School
Floor Location : J 216 F

To determine how does the amount of time in the microwave measured by seconds affects the growth of bacteria, as measured by the percentage of the petri dish surface. According to the experiment, Microwave ovens use electromagnetic radiation to heat water molecules in food. Therefore, if the amount of time in the microwave increases, then fewer bacteria are likely to survive since most bacteria live in 45 Celcius.

As being stated before in the hypothesis, if the amount of time in the microwave increases, then fewer bacteria are likely to survive. Most bacteria, like Prokaryotic bacteria, has a shell that protects itself composed mainly of structural carbohydrates and which helps maintain cell shape. High-temperature damages the shell that protects the bacteria so the bacteria without shells literally will not survive anymore due to the extremely high temperature. According to study, most bacteria do not live above 120°F and as the increment of temperature would kill more of them. At 102°F, most bacteria can no longer reproduce, which is the protective nature of human fevers. Therefore, longer time in microwave sterilizes more bacteria.

The experiment proved the hypothesis by having the collected data that shows when the time in the microwave (measured by seconds) increase, more e-coli (measured by the percentage of the whole surface) would be killed. According to the data, when the time in the microwave increased from 0 seconds to 5 seconds, more e-coli would be killed depends on the increment of temperature. Therefore, the heat microwave produced killed e-coli by clearing the surface of e-coli. To identify whether the e-coli is dead or not, it is important to check the surface of the petri dish and see if there is any transparent circle or not. Those circles represent the e-coli being killed. Overall, by checking those transparent circles and estimate the percentage of e-coli that covered the petri dish. The hypothesis is being proved by the experiment.

There are multiple scientific reasoning to support the hypothesis and the data. One of the most straightforward explanations of why e-coli is being killed by high temperature is the high-temperature damage the shell for e-coli to isolate heat. Therefore, bacteria are likely going to die when the temperature passes 102°F. The heat breaks down the hydrogen bonds holding the protein structure in shape. Therefore, the higher temperature would kill more temperature.

The relationship between time being microwaved and e-coli being killed increases at the same time. For example, 5 seconds of microwaving would kill more e-coli than 2 seconds of microwaving.