![]() ![]() There was a pack of blades in each kit and we would just replace the blades every time we used one. Of course, it was a basic class so we only ever used a couple of the scalpels. Made me feel like a mad scientist or something. The required set of scalpels was in a very nice leather case and it was quite thrilling to put on a white doctor's coat and take out all these different looking pointy things. I was always quite nervous when I used my scalpels in biology classes, even though I really enjoyed that class. So, yeah, don't try to mess around when you are using those things. He was a pretty good teacher as well, I never thought of him as being that strict, but I guess they really have to make sure no one is going to get hurt.Īnd those scalpels are sharp enough that one wrong move could seriously injure someone. I don't think they were really in any danger of hurting anyone.īut the teacher basically threw them out of the class and they both had to grovel quite a bit in order to get back in again. I think they were doing a miniature sword fight sort of thing, not really being too bad I guess. I remember when I was in a biology class a few years ago, a couple of the guys in the class started getting a bit silly with the scalpels. Just make sure you get a scalpel that's easy to hold and that you aren't going to get too cramped using, as paper cutting can take a - Yeah, the teachers all take the safety aspect pretty seriously as well. I would never go back to using scissors for this kind of work. I guess I used them because I had always used them as a child and it never occurred to me to use anything else.īut, I like quite lacy looking designs and it was getting harder and harder to cut them out using the scissors.įinally I gave in and bought a craft scalpel and I have to say, it is absolutely wonderful. Metals are hardened to make the crystallites (grains) smaller, but isn't that adding imperfections to the crystal structure? Meanwhile, the obsidian won't deform because the crystallites aren't aligned, so it will keep the sharper edge but it's more brittle and can shatter if dropped.I do a fair bit of scrapbooking and I lways used to use scissors whenever I wanted to cut anything. So the problem is due to the fact that metal is malleable, which is a result of properties of its crystalline structure. Metal can be shaped as such, but it has to be steeled periodically because it deforms. The conchoidal fractures can create an angle that's ideal for sharpness. My experience in this is based in geology, so I don't know very much about metals, but I think the issue is that it's simpler to use obsidian than steel to get an extremely sharp edge that won't deform. That's why you get conchoidal fractures, right? It's the lack of a crystal structure that allows it to break like that. Obsidian/glass is an amorphous solid, so it doesn't have any crystal lattice. I think my confusion may be because you go from talking about a perfect crystal lattice to grain size, but I'm not sure. I don't know wether it is technically possible to make a steel edge that thin yet, but the materiel allows for it. Once you try cutting something, the steel edge will bend, and become less sharp. At that thickness, the steel blade's serration's (the ones I mentioned earlier) are too weak, and will bend once you try to use that edge. At molecular width, it's edge is hard enough to maintain that razor edge. Obsidian is much, much harder than steel. Steel can theoretically be honed until its edge is just a single molecule wide like obsidian, but here the limitations of the metal come in to play. Steel can be honed to make that cutting edge thinner, and thus, sharper. When you sharpen a knife, you are aligning the serrations to the plane of the edge. Those points will bend to either side of the blade through use,dulling the edge. Steel, on the other hand, is jagged on the edge, forming tiny tooth-like serrations on the cutting edge. Freshly broken pieces of obsidian make perfect, smooth edges that are only a molecule wide at their apex.
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