student124
Posts: 1
Joined: Wed Dec 21, 2005 10:57 am

Effect of UV light on bacteria mortality

Postby student124 » Wed Dec 21, 2005 11:10 am

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.

hostsha
Former Expert
Posts: 24
Joined: Mon Sep 19, 2005 6:48 am

Postby hostsha » Fri Dec 23, 2005 7:21 am

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

thetrans1ent
Posts: 31
Joined: Wed Sep 14, 2005 3:35 pm

Postby thetrans1ent » Sat Dec 24, 2005 7:44 pm

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.


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