Science Buddies: "Ask an Expert"

I am just starting my science project for biology, and decided to do it on effect of UV light on bacterial mortality. I have been given permission to culture bacteria at school, but I dont know which bacteria to use which would
A) work in the experiment by being effected by UV, and give good results
B) i would be permitted to use at school i.e. not pathogenic

I also dont know how to quantify or measure mortality of bacteria in order to get good results. I would appreciate any replies, so please dont hesitate to answer and provide any information which you think might be useful.

Student124,

A) work in the experiment by being effected by UV, and give good results

This part is for you to do. You state the hypothesis for the experiment and plan the experimental procedure.

B) i would be permitted to use at school i.e. not pathogenic

In k-12 classroom, Escherichia coli (non pathogenic) is generally used.

I also dont know how to quantify or measure mortality of bacteria in order to get good results

1. Plan to expose bacteria culture (agar plates) to UV light for various lenght of time. (variable)
2. Control bacterial culture is not exposed to UV light.

Calculate percent survival: Average colony count in treated/Average colony count in control.

I hope this helps.

HostSha
Secondary School Teacher

You could also set the variable as the strength of the UV light (e.g. 0 W, 150 W, 300 W, etc).

As already stated, E.coli can be used. I believe yeast works also.