What happens to uv rays in bacteria

What Are The Effects of UV light on Bacteria Mortality

Abstract

I investigated whether or not ultra violet lights will affect the mortality of bacteria. I predicted that the UV lights would kill the bacteria. I was trying to find out if the world could use UV lights as an improved method of killing bacteria. For example, instead of having to use Lysoland or other cleaning products that have chemicals that can be harmful to the skin and the environment, we could use UV lights instead. Lots of people each year are getting injured or ill by cleaning products because of what's in them. In fact, some “green” cleaning products, like Clorox Green and others have chemicals in them that don’t kill germs at all. The chemicals in the products can irritate the skin, eyes, and lungs. Not only would this new method eliminate harmful chemicals, but would also eliminate packaging for these products. It would be extremely beneficial to the environment. This is what inspired me to perform this experiment.

After rubbing my hands on the floor, I swabbed them for bacteria. I then transferred the bacteria to the plates. Next, I put the agar plates under the UV lights for times ranging from 30 seconds to 30 minutes, except for the control. When that was done, I put them underneath a heat lamp to see if the bacteria would grow or die. I used a simple sampling technique to count the bacteria colonies on each plate. I also cultured a control plate to make sure the plates were not contaminated prior to the experiment.

My testing consisted of measuring the constant strength of ultraviolet light in 30 second increments starting from 30 seconds and ended up with thirty minutes. The strength of ultraviolet light was constant but the length of time increased. My results came out to be inconsistent. It showed that the bacteria went down then up then back down and up then down then up. From zero minutes to five minutes it decreased, from seven minutes to ten it increased, from ten minutes to twelve it decreased again, then for fifteen minutes it increase, then from there seventeen minutes to 30 minutes it decreased.

When doing this project I learned that there are different types of bacteria that are found to be resistant to uv ray lights. In my hypothesis I thought that the bacteria would die underneath the UV ray lights, but my hypothesis was wrong. It came out to be that there are different kinds of bacteria that are stronger than others that can’t die underneath the UV ray light. I feel that my findings show there were many different types of bacteria because it went from low to high with the same strength of UV lights so, that must show that there has to be some of the bacteria was stronger or resistant to the different types of bacteria. I suspect this is because the light was not strong enough. If I could improve this experiment I would use a stronger UV light and use some other different bacteria to see if the UV lights would kill that bacteria.

In my project, "What are the effects on bacteria Mortality?" I found out if the UV light would kill the bacteria or do nothing to it.

Hypothesis

I predicted that the UV light would kill the bacteria.

Procedure

1. Dirtied my hands in hallway

2. Put the cotton swab in water

3. Rubbed the cotton swab on my hand

4. Rubbed dirty cotton swab on petri dish

5. Put petri dishes under the UV light

6. Timed them

7. Put them underneath a heat lamp

8. Put a black piece of paper on top of them

Conclusion

I thought that the UV light would and up killing the bacteria, however my results were inconclusive.I believe that this was due to the lack of strength in the UV light.