I won't necessarily say that. She was curious enough about the result to repeat the experiment and do what amounted to a ranging study where she used increasingly small doses to test potency. That shows curiosity and the use of the scientific method. She's not stupid and she did approach with an open mind which is what we want.
She's uneducated. She hasn't taken a microbiology course to understand what she's actually experimenting on or a pharmacology course to understand what amoxicillin is expected to do. FIrst of all, we didn't specify what type of bacteria were on the plate. Given the nature of a high school science experiment we can expect the usual indoor airborne aerobes, a healthy dose of skin bacteria from the inevitable contamination, and probably a fair amount of yeasts and molds in the air to hit that plate.
Amoxicillin, like any antibiotic has a specific spectrum of activity, the set of bacteria species it'll kill. If you're curious, check out the antibiogram here (first image). The key here is that whatever mix of species end up on that test plate, amoxicillin is only going to reliably kill some of them. As a treatment strategy, we use it to kill the organisms most likely to be causing the infection, or kill them enough that the immune system can clean up the rest. We would not expect this drug or any of them really to kill everything on that plate, especially not the yeast or mold contaminants. The expected result here is that the species it didn't kill would overgrow the plate.
Meanwhile the oregano's a bit more of a conundrum. We're using an essential oil, which means we get a broad mishmash of lipophilic molecules that extract into that oil. Who knows exactly what's in it or in what concentrations? What we do know is that it's oil. We're putting it on top of an agar gel which is hydrophilic. So oil repels water and forms a film over the top of the gel. This block circulation of oxygen to the critters attempting to grow on the gel. Since they're all aerobic and require oxygen to live, the oil itself kills them, whether there was anything of substance in the oil or not. There may be something there that kills bacteria. We simply don't have the right test to determine that.
Your teacher… she sounds stupid.
I won't necessarily say that. She was curious enough about the result to repeat the experiment and do what amounted to a ranging study where she used increasingly small doses to test potency. That shows curiosity and the use of the scientific method. She's not stupid and she did approach with an open mind which is what we want.
She's uneducated. She hasn't taken a microbiology course to understand what she's actually experimenting on or a pharmacology course to understand what amoxicillin is expected to do. FIrst of all, we didn't specify what type of bacteria were on the plate. Given the nature of a high school science experiment we can expect the usual indoor airborne aerobes, a healthy dose of skin bacteria from the inevitable contamination, and probably a fair amount of yeasts and molds in the air to hit that plate.
Amoxicillin, like any antibiotic has a specific spectrum of activity, the set of bacteria species it'll kill. If you're curious, check out the antibiogram here (first image). The key here is that whatever mix of species end up on that test plate, amoxicillin is only going to reliably kill some of them. As a treatment strategy, we use it to kill the organisms most likely to be causing the infection, or kill them enough that the immune system can clean up the rest. We would not expect this drug or any of them really to kill everything on that plate, especially not the yeast or mold contaminants. The expected result here is that the species it didn't kill would overgrow the plate.
Meanwhile the oregano's a bit more of a conundrum. We're using an essential oil, which means we get a broad mishmash of lipophilic molecules that extract into that oil. Who knows exactly what's in it or in what concentrations? What we do know is that it's oil. We're putting it on top of an agar gel which is hydrophilic. So oil repels water and forms a film over the top of the gel. This block circulation of oxygen to the critters attempting to grow on the gel. Since they're all aerobic and require oxygen to live, the oil itself kills them, whether there was anything of substance in the oil or not. There may be something there that kills bacteria. We simply don't have the right test to determine that.
Interesting and logical, thanks.