Again, thanks for the guidance!
We like your idea of using sterile disks for the Kirby-Bauer disk-diffusion method. Thank you for the very helpful information.
We have run into a few more questions.
What type of paper disks should we get. I am unfamiliar with this product. What I am finding is incredibly expensive for the small ones in a vial. The ones I think we can use are a little better in price, but way too big for our use, I mean bigger than the agar plate itself. Are there other options, less expensive that would still be sterile? The only thing I could think is to use the bigger ones, sterilize my hole punch, and make them smaller. lol. I'm not sure this would introduce bacteria. I am really wondering if there is something I am missing as far as price, or if I'm looking for the wrong thing. All suggestions are welcome.
Just now saw these, are these it?:
https://www.carolina.com/microbiology-s ... erile+disk
Also, he and his dad built an incubator, yay. We have read multiple experiments, is the bacteria supposed to be at 90-98.6 degrees Fahrenheit? And are the agar plates ok in the incubator by themselves, Or should we put them in a plastic bag too for extra protection? Or use saran wrap for extra protection?
We were thinking ahead about a workspace to be sterile. Any suggestions for doing it at home? Maybe a plastic serving tray we can wipes down before we start with disinfecting wipes? or alcohol?
One more thing,
For the agar plates, we brainstormed how to mark them so we can do this experiment twice. We have 20 disks. We came up with three cenarios:
1. one agar plate be the control, one plate have just oil (to be sure the oil doesn't produce bacteria), then the other plates divide into 1/4 pie sections with sharpie on the back of the bottom. each section marked with an individual oil he chose to use.
- this would let him choose 4 oils
- it would allow him to have 4 results from the same oils
- and it would allow him to do his testing 3 times. (one being someone following his procedure, which is required.) (This would give a total of 12 results from each oil)
2. one agar plate be divided in 1/2 with the left side as the control, the right side with just oil (to be sure the oil doesn't produce bacteria), then the other plates divide into 1/2 sections with a sharpie on the back of the bottom of each section, the same oil in both sections per plate.
- this would let him choose 5 oils to test
- this would give him 2 results from each oil
- and allow him to test 3 times too (so 6 results altogether)
3. The last option is to have one agar plate as the control, another place be with just oil (to be sure the oil doesn't produce bacteria), then use 1 plate per oil, the plate marked on the bottom with oil used.
- this would let him choose 5 oils to test
- this would give him 1 results from each oil
- and allow him to test 2 times (so 2 results altogether)
What are your thoughts?
Is it better to have more results? so you know your experiment is verifiably consistent? or are we overthinking. We like a portion of the last example we came up with because we could potentially add another disk and see if the potency of the oil would change the outcome, but that may change his goal. So, trying to keep it simple.
Thanks again for helping! We really do appreciate it. He is looking forward to getting started and doing it after all this prep we have done and advice your have given!
Truly...thank you every time!