I'm having trouble with two things.
First is solubility- sometimes I mess up and I get a soluble powder like calcium nitrate to appear as if it couldn't dissolve, at least at first. Is there a good way to ensure I got consistent results while dissolving powders quickly (since time is so important in this event)? Should I stir or no?
The other problem is that at least when I look at hairs under a microscope I can never see the shape of the hair, just a black strip, which makes them all look the same. Am I just using low quality microscopes? Should I try changing the height of the slide? Or am I just bad at seeing?
Solubility - yeah, sometimes it can be hard to tell. But I'd say if normally soluble powders are appearing like they don't dissolve, it might be because you put too much powder and not enough solvent. For example, with water, for a certain volume of it, there's a threshold on how much powder it can dissolve (and this "threshold" amount also varies from powder to powder, based on Ksp), and any more beyond that threshold will cause a solution to be saturated, in which no additional solute will dissolve. So in other words, you may have saturated your solution.Okay, for hairs are you allowed a microscope at the competitions?
At MIT, we had to identify by feel, touch, and taste if you yolo-ed---no microscopes were provided.
To answer AllenWang314's question - yes, you can use a microscope for hairs. That's pretty much the only tool you have to confirm the identity of hairs, actually. I can also tell you that taste won't tell you anything about the hairs.
To answer Karp's, idk tbh since I don't know what your microscopes may look like. If you see a thin black strip, you might not be using a high-enough power lens. When I used to do it, I think I always used whatever the highest power lens was. This is especially since hairs are usually so small, you probably won't be able to see much with the low power lens. So in your terms, the height of the slide to some extent, also depending on which lens setting you're on. Even then, it might be hard to see and at that point I might rely on touch.