technokinesis
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Temperature for Incubation of Petri Dishes: LB Agar Plates

Postby technokinesis » Wed Jan 27, 2021 9:15 pm

:?: Question :?:

Hello,

Here are the steps I did for my science experiment,
    I coughed on Luria Broth agar plates with three different face coverings (surgical, cloth, neck gaiter) and no mask.
    I then sealed the plates with masking tape and labeled them.
    I put these plates into a plastic container next to a portable heater and a lamp.
I measured the temperature the next day and it was 104 degrees Fahrenheit. I immediately turned off the lamp and adjusted the temperature and positioning of the portable heater and then the temperature went to 93 or so degrees Fahrenheit.

The DIY incubator and plates were at the temperature of 104 degrees for about 14-16 hours. It's been two days since I started this project and I haven't seen any bacterial colonies on my control group (the no mask trial). I'm unsure if the high temperatures killed the bacteria from my cough. Should I unseal the Petri dishes, cough on them again (redoing the procedure), and reincubate?

If it helps, these are the Petri dishes I ordered: https://www.amazon.com/EZ-BioResearch-Bacteria-Science-Book/dp/B0165PQST0/ref=sr_1_1?dchild=1&keywords=EZ+BioResearch&qid=1611806294&sr=8-1

Picture of my incubation set up before I removed the lamp, the lamp is now removed to reduce the temperature: https://prnt.sc/xqkbq7

Please respond to this and help me as soon as possible, as my project is due in 5-7 days.

Also, do you have any name ideas for this project? I was thinking, "Stop the Spread!" or "Viruses". Any suggestions are accepted! :D

probiotics
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Re: Temperature for Incubation of Petri Dishes: LB Agar Plates

Postby probiotics » Wed Jan 27, 2021 10:18 pm

Hi!

That's a timely project! While 37 degrees C is the average optimal temperature for bacteria to grow, I don't believe 40 C is high enough to kill your bacteria. Additionally, 2 days is probably too short of a time for you to begin to see bacterial growth. However, these are hypotheticals since the bacteria coughed onto the plate is unknown and is probably a mix of many different bacteria. I'd recommend giving it a few more days, or, if you have extra Petri dishes, repeat the experiment separately to ensure you get results. Good luck!

- probiotics

technokinesis
Posts: 8
Joined: Sun Oct 04, 2020 3:05 pm
Occupation: Student

Re: Temperature for Incubation of Petri Dishes: LB Agar Plates

Postby technokinesis » Wed Jan 27, 2021 10:34 pm

Thank you for the response, probiotics!

How long would it take to see results then? A week maybe? My biggest concern is contamination of the plates but I did three trials so hopefully it’ll work.

technokinesis
Posts: 8
Joined: Sun Oct 04, 2020 3:05 pm
Occupation: Student

HELP! Is this normal for Petri dish incubation?

Postby technokinesis » Fri Jan 29, 2021 5:25 pm

I am doing a project on the efficacy of different face coverings and coughed on to multiple Petri dishes.

There is condensation on the lid of my Petri dish and there have now been water streams appearing in the lid. The Petri dish is inverted, so it is not contaminating the agar or disrupting results.

Is this normal? What do I do to fix it?

Also, I am "incubating" the Petri dishes through the medium of an incubator that constantly blows 75 degrees Fahrenheit air on the plastic container the dishes are in, keeping them at around 85 degrees surface temperature and 93 degrees body temperature. Should I use surface temperature to measure the temperature or body temperature?

These dishes have been incubated for about four days and I haven't seen any bacterial growth yet, I'm thinking I should wait a week, and if there is still no growth redo the project. What do you all think?

There was some contamination I believe with the project, so hopefully, that doesn't greatly affect the results. I believe there was some lint or dirt of some kind that touched the lids and then also air exposure, but the air exposure was in the same environment for the same amount of seconds when conducting the experiment.

ALSO!!! Please vote on board names!
    1. Stop the Spread
    2. Viruses
    3. Face Covering Efficacy
    4. Measuring the Efficacy of Different Face Coverings
    5. How effective really is your mask?
    6. Mask Up!
    7. Mask Up (State Abbreviation)!

Any other suggestions are appreciated, thank you! :)

MadelineB
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Re: Temperature for Incubation of Petri Dishes: LB Agar Plates

Postby MadelineB » Sat Jan 30, 2021 3:09 pm

Hello technokinesis,

I've merged your most recent post with the thread for your previous posts. Science Buddies requests that you keep your posts together in the same thread so the experts who have been helping you can more easily see that you have follow-up questions.

I've also removed the duplicate of your most recent post. Again, Science Buddies requests that you not post duplicates.

And thank you for your patience waiting for experts to reply to your posts. The experts are volunteers and thus may not be able to respond immediately.

Good luck with your project!
Madeline
Moderator

hummch
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Re: Temperature for Incubation of Petri Dishes: LB Agar Plates

Postby hummch » Wed Feb 03, 2021 1:47 pm

Hi technokinesis,

Having condensation on the lids of your Petri dishes is common, but not preferred as it makes looking into your dishes difficult and can saturate the materials inside of the dish. I recommend asking a search engine about how to reduce the condensation.

My thoughts are that you should use the body temperature as that is the temperature that your bacteria is experiencing. Though I am not experienced in bacteria growing, so another expert may be able to refute my statement or comment on this further.

As for your topic, my favorite titles are 4 and 5 as they are relatable and will make viewers stop and think about whether their masks are effective or not.

I hope this helps! Let us know if you have any further questions.
Cat


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