Hi!
Thanks for replying.
About the gram-staining: we have some more questions.
There are some materials that we're concerned about. They are:
- Light Microscope
+ We have easy access to a light microscope. There are three objectives on the ones at our school: 4x mag., 10x mag., and 40x mag.. Of course, there's the 10x lens within the eyepiece, so everything is multiplied by 10. However, the WikiHow says: "Bacteria vary greatly in size, so the total magnification required will vary from 400x to 1000x." Our
maximum available magnification is 400x. Will this dramatically impact our ability to look at the bacteria? After all, really, all we're looking for is if there are noticeable amounts of gram-neg bacteria, which (should) easily show up as pink.
- Methanol
+ Or, should we use a Bunsen burner? Would our school have a Bunsen burner? We thought it may be better to stray away from the burner, but after googling "methanol," we realized that it is toxic. How toxic is methanol, really? Would our school have it?
- Crystal violet
+ The WikiHow recommends "Hucker's" crystal violet. Will we need this particular brand of stain? Or any crystal violet?
+ You mentioned that our school may have it, but in the case that it doesn't, that we should seek a local high-school. Though this isn't really related to science, how would you recommend us to get in touch with a local high-school? Would we email a science teacher?
- Decoloriser
+ A 1:1 mix of acetone and ethanol is what it recommends. Do we have to mix this on our own? Or are decolorisers already mixed? Would our science dept. or a local high-school dept. have some? If they don't have the decoloriser itself, would they possibly have acetone and/or ethanol?
+ The WikiHow says that it "typically takes under 10 seconds" for it to work. How will we know when to stop? "Stop immediately, or the decoloriser will remove the crystal violet stain from both gram-positive and negative cells, and the stain will have to be repeated," it says, and we're a little scared that we're going to over-do it.
Should we simply eyeball it? Is there any obvious, visible change as we look at it?
- Counterstain
+ The WikiHow talks about safranin or fuchsin as the counterstain.
Do you think that our school will have these materials? We're in 7th grade and our school has students in grades 6-8 only.
We don't want to spend much. The agar plates were a decent expense.
If we were to swab a surface with a sterilized swab and proceed to complete the gram staining test within, say, an hour of swabbing, would the test results be accurate? I know that we can't have anything over 48 hours, but can we have anything less? Or does it have to be at least 24 hours old? How would we grow it? Does it even have to
be grown? Would it grow directly on the microscope slide? Would they somehow multiply on the swab itself? So many questions.
You've been
ENORMOUSLY helpful and we can't express our gratitude enough. We're most definitely going to give you acknowledgements on our poster.
Can't wait to hear back. We're genuinely excited to see your next reply. Thanks so much.