small beige dot. Sometimes the colonies grow together in large patches which are called lawns and the counting methods will be adjusted to approximate the number of colonies. The first variable that will be tested is the duration of time exposed to the ultraviolet light. The ultraviolet light is germicidal, or in the UVa wavelength range. As the duration of time increases, the amount of colonies should decrease because more photons are absorbed by the of the bacteria and therefore more cells will die because they are not able to replicate. The second variable that will be tested is the distance away from the ultraviolet light. According to physics teacher Mr. McMillan, as the distance from the ultraviolet light increases, the amount of colonies should increase. This is because the intensity of the ultraviolet light waves, or the number of photons decreases as the distance from the ultraviolet light increases in accordance to the inverse square law ("Inverse Square Law"). The inverse square law states that as the distance doubles from a light source, the intensity reduces to 25% of its original state, so the number of photons decreases drastically as the distance increases. Throughout the experiment, E. coli will be grown and exposed to ultraviolet light. E. coli will be transferred to Petri dishes with nutrient agar and they will then be subjected to an ultraviolet light in a goggle sterilization cabinet. The Petri dishes will be grouped and exposed for different amounts of time and different distances and then they will be placed in an incubator. After the incubation period, the number of colonies for each dish will be counted and recorded, and any observations will be recorded.
small beige dot. Sometimes the colonies grow together in large patches which are called lawns and the counting methods will be adjusted to approximate the number of colonies. The first variable that will be tested is the duration of time exposed to the ultraviolet light. The ultraviolet light is germicidal, or in the UVa wavelength range. As the duration of time increases, the amount of colonies should decrease because more photons are absorbed by the of the bacteria and therefore more cells will die because they are not able to replicate. The second variable that will be tested is the distance away from the ultraviolet light. According to physics teacher Mr. McMillan, as the distance from the ultraviolet light increases, the amount of colonies should increase. This is because the intensity of the ultraviolet light waves, or the number of photons decreases as the distance from the ultraviolet light increases in accordance to the inverse square law ("Inverse Square Law"). The inverse square law states that as the distance doubles from a light source, the intensity reduces to 25% of its original state, so the number of photons decreases drastically as the distance increases. Throughout the experiment, E. coli will be grown and exposed to ultraviolet light. E. coli will be transferred to Petri dishes with nutrient agar and they will then be subjected to an ultraviolet light in a goggle sterilization cabinet. The Petri dishes will be grouped and exposed for different amounts of time and different distances and then they will be placed in an incubator. After the incubation period, the number of colonies for each dish will be counted and recorded, and any observations will be recorded.
rouditchenko-zanetti_biology_research_paper.docx