There's an interesting discussion at Pharyngula and Uncertain Principles about a high-school physics teacher in California who is in trouble for firing a gun as part of a classroom demonstration. It's interesting because it opposes two principles to which we bleeding-heart liberal academic types will generally be sympathetic: "guns are dangerous" vs. "teachers should be free to make their classes interesting and exciting." In the comments it's very clear that, not only are people disagreeing, but they find folks on the other side to be slightly nutso. I'm happy to come down on the side of an interesting classroom in this case. Guns can certainly be dangerous, and we have some cultural issues here in the U.S. that cause special problems that most other countries don't have. It's far too easy for the wrong people to have guns, especially handguns and assault rifles and other darlings of the NRA. But it goes way too far to extrapolate to the idea that the very concept of a gun is somehow evil, and that the things should be banned entirely.
The teacher, David Lapp, demonstrates the ballistic pendulum experiment each year by shooting a bullet into a block of wood. By measuring the block's recoil, you can figure out the velocity of the bullet using conservation of momentum. (Or "inertia, velocity and other complex formulae," as the newspaper article would have it.) Sure, there are ways to do it without using a rifle, but a demonstration like this makes the experiment come alive for a lot of students. Many commenters in PZ and Chad's threads are absolutist about the issue, insisting that any appearance of a gun in a classroom is completely insane. But the basic arguments against allowing the gun are pretty simple: either (1) there is a safety risk in having a gun in the classroom, or (2) it sends the wrong message to kids to let them see guns. I think (1) is blown substantially out of proportion. Imagine, in any of these arguments, replacing "gun" with "a dangerous thing." Should there be an absolute prohibition against every dangerous thing in a classroom? No hazardous chemicals, no driver's ed, no power tools in shop class? Dangerous things should be handled with care, but that shouldn't lead to a complete loss of perspective. The second argument, that simply letting the kids see a gun up close leads to familiarity and it's a short step from there to Columbine, has it exactly backwards. The reason why American students go to college and engage in frequent binge drinking and other irresponsible behavior isn't because they are exposed to alcohol too much in high school -- it's because the concept of underage drinking is a taboo that they can't wait to violate. In other countries where children are allowed to drink in responsible amounts in a respectable context, there isn't any outlaw romance associated with the concept of getting completely plastered once you escape from your family, and the rampant alcohol abuse that U.S. colleges have to deal with is much less widespread. I'd be very happy if the total number of firearms in American households were dramatically lower than it is, but I'd also be happy if kids were taught basic gun safety, and thought of them as tools to be used properly rather than toys out of movies and comic books. And if they learn some conservation of momentum and other "complex formulae" in the process, so much the better.
