UV Light

The UV wavelength has the unique property of being able to kill microorganism. This really cool feature is being studied scientists and in some hospitals they use UV lights as a sterilization method to clean hospital rooms after a sick patient leaves. However, UV light is also known to cause mutations, and so in a hospital setting only the longer UV Light C wavelength us used just in case someone was to walk in the room by accident.

UV Light bulb and Petri dishes undergoing sterilization.

In Lab we decided to see if this was true and if UV light would kill or retard the growth or our bacterias. Everyone made a carpet spread of bacteria on a Petri dish. Since UV light is blocked by any physical barrier except air, to conduct the experiment we simply covered half the Petri dish with paper, and exposed each dish to one minute of UV light. Oh, and remember to take the glass lid of the Petri dish because that will block UV light too! Next lab we checked the dishes and found that there was still bacterial growth on the UV treated side of the plates, but it did seem to be a little less growth then the non-UV light treated side. We thought that maybe the experiment did not work very well because we set the wave length on too low a setting. No one checked the setting before we began.