Death Rays: What Duration of Ultraviolet Exposure Kills Bact

[handcok]

Hi I am doing this experiment that I got in this website. I was wondering why a bunsen burner was necessary for the project. It is on the materials list. I am also wondering if it is completely necessary for the 200ul pipette to automatic. Also what is the bent glass rod and why is it necessary. The last thing I need is where to buy a shortwave uv light and what is a good model? Please Help. Thank You.

[sunmoonstars]

Hi,

I see you are doing this project: https://www.sciencebuddies.org/science- ... p017.shtml

I can help answer your questions:
I was wondering why a bunsen burner was necessary for the project. It is on the materials list. I am also wondering if it is completely necessary for the 200ul pipette to automatic. Also what is the bent glass rod and why is it necessary. The last thing I need is where to buy a shortwave uv light and what is a good model?

The bent glass rod is for spreading the bacteria on the plates. The bunsen burner is to heat the glass rods so you can bend them (and it sterilizes at the same time). The pipettor does not need to be automatic - any tool you can use to acurately measure will work fine. You can get a UV light (and the protective eyewear) at home-supply stores, or on Amazon (something like this one or similar will work fine - http://www.amazon.com/LEDwholesalers-Ul ... s=uv+light)

Let me know if you have any other questions.
Tonya

[klhjbh62604]

Hello:

Tonya has provided you with great information.

I wanted to add that if you can find sterile inoculating loops, you can use these for your plating rather than using a bunsen burner and glass rods.

Kati

[deleted-155550]

Hello,
I am planning on doing this project. I have spent about half an hour looking through the project I was wondering if you COULD do it at home without harming ourselves or our family. I go to middle school and if this does harm us, would it not harm others at school? I am saying this because I have no idea how this UV ray machine is. There is this place called Kraton and I know someone who works there. I'm not sure if going there would do the trick. Do shed some light.Will this machine only affect a corner of a room? If this going to only last a couple hours, I could not anybody near it.

[sunmoonstars]

Hello,
I am planning on doing this project. I have spent about half an hour looking through the project I was wondering if you COULD do it at home without harming ourselves or our family. I go to middle school and if this does harm us, would it not harm others at school? I am saying this because I have no idea how this UV ray machine is. There is this place called Kraton and I know someone who works there. I'm not sure if going there would do the trick. Do shed some light.Will this machine only affect a corner of a room? If this going to only last a couple hours, I could not anybody near it.

Hi Dwarkesh,

Right, the UV light is not good for humans, either. A quick flash wouldn't do much noticeable damage, but any prolonged exposure should be prevented. You could do this at home, but since working with bacteria, please be sure to get familiar with the precautions here:

Also, in general, when working with bacteria, I try to stay away from working in areas where food is kept - like the kitchen. Find a different place to do your work and it should be as safe as working at the school.

https://www.sciencebuddies.org/science- ... fety.shtml
Tonya

[deleted-155550]

None of the teachers in my school have an incubator. What can I do?

[sunmoonstars]

Hi, this page explains about growing bacteria in an incubator, and directions to make a light bulb incubator: https://www.sciencebuddies.org/science- ... Agar.shtml

Enjoy!
Tonya

[deleted-155550]

Hi Again
My teacher says I can do this without an incubator. It would just take longer. Is that okay. Second, I looked up pipettors and they are above a hundred dollars.

[sunmoonstars]

Hi Again
My teacher says I can do this without an incubator. It would just take longer. Is that okay. Second, I looked up pipettors and they are above a hundred dollars.

OK, I only see one place where you need the pipettor - when measuring out the initial 100 uL of E. coli. Let me know if you see it in other places in the protocol... Maybe it would be possible to check if another class/teacher has a pipettor for you to borrow. It is pretty important to measure the bacteria you deliver to the plate because you need to know that the amount delivered to each plate is kept constant among the different plates. If you HAVE to, you may be able to estimate using a pasteur pipette, or better yet, a small syringe that can measure 1/10 or a ml. Do you think you can get creative and find a way to deliver the E. coli? Let me know what you come up with and what other help you may need.

Tonya

[deleted-155550]

My bacteria are growing and I did shine 395nm uv light at them at the times suggested by this project but no difference was noticed between the control group and the group that received 300 sec. of light. In fact, that grew better.

[sunmoonstars]

Ok, I suppose you were able to figure out how to get the bacteria plated. That's great!

How far away from the light source were the bacterial plates? Can you give me your data? - The actual colony counts from each half of each plate?


Did anything strange happen during your procedure?

Thanks,
Tonya