On 02/25/2011 09:19 PM, Harry Veeder wrote: > Jed Rothwell wrote: > >> The worst example was the Correa claim that a stationary gold leaf >> electroscope >> does work. No, it doesn't! It isn't a little guy standing with his arms out. >> >> >> > He claimed to have electrical evidence that a stationary gold leaf > electroscope > does work. > I assume your rejection is based on a critique of the evidence rather then > just > the belief that it is physical nonsense. >
Actually, the problem is deeper and simpler than that. The *fact* that the Correas were off in la-la land on that one is based directly on semantics and pure logic, not on anything else, and that is why it's a "fact" rather than an "opinion". "Does work" means something specific in physics: "Work" is force times distance. When distance moved is zero, work done is zero. work = force * distance (says Newton) The little man with his arms sticking out is also not "doing work", no matter what you or the little man may think. Once again, it's the definition of "work" that tells us this. Now, before you say, "Steve's full of it here, the little man's breaking a sweat" I need to point out that a solenoid with movable core which is holding a lever in position -- say, for instance, holding the little man's arms in position (the little man is a robot in that case) is also *NOT* "doing work" despite the fact that it's getting hot. The solenoid in the robot, and the muscles in a human, DISSIPATE ENERGY. That's for sure! But they don't "do work" in the process; they just produce heat. Doing work produces kinetic energy; generating heat in a solenoid, or in a muscle, does no more "work" than dissipating heat in a resistor. Of course, whether something is "doing work" is also somewhat dependent on the point of view. At the smallest scale, the electric field in the resistor "does work" on the electrons. But in the macroscopic view, we get no "work" out of a resistor; we just get heat. You could, of course, argue that producing heat is "doing work" in that particles are being accelerated, which means force*distance is nonzero on those particles, which means, in turn, that "work" is being done. And that's fine, too, it's semantics and semantics are just whatever we agree on; this new, more complex definition of work looks something like this: work = force * distance + generated heat And once again, by definition, it's nonsense to say the electroscope is doing work, because not only is it just sitting there, it's just sitting there at *constant* temperature -- it's not getting hot. "Electrical" evidence is not relevant in this case; only if they can show that fixed-geometry systems with an electrostatic charge spontaneously warm up can they claim that something is "doing work". Now, it is quite possible that the Correas have REDEFINED "work" to mean something other than force times distance, or force times distance plus waste heat. In that case, they are just being unclear and obfuscatory rather than totally muddleheaded. But in the absence of some stated definition for the term "work" which includes stationary systems with fixed geometry, the simplest conclusion is that they're clueless.
