Well, one difference between “heat conduction” and “phlogiston” is that the former carries some additional information with it—heat conduction is a well-understood mechanism by which energy is transferred from place to place. Maybe it does apply in that situation and maybe it doesn’t—in the example given, it doesn’t, there’s no heat-conduction mechanism to transfer heat from one side to the other—but the fact that there’s actually a mechanism behind the words separates it, qualitatively, from an explanation like “phlogiston.” It has equations behind it which can then be written down and tested for agreement with reality.
Really, I can quite understand the students… if you say “I don’t know” you have a zero percent chance of getting the explanation right. If you say “that seems impossible,” then you’re guaranteed to get it 100% wrong—since it DID happen, and thus it must be possible. The best course of action in the situation is to think of all the hypotheses you can, and then guess at one of them—whichever one has the highest chance of being right, given what they know about physics.
Now, I certainly hope that the students wouldn’t think that by throwing around guesses they’re “doing physics”—yes, doing physics would involve taking actual measurements, and I would hope that after taking some measurements of the block over time they would see “oh, this isn’t actually at equilibrium like we had all assumed.” (Alternatively, if a student took the words and wrote down an actual model of how the air currents or the different metals or the heat conduction could lead to the observations, that would also be “doing physics”, though the only end result of it would be to yield a mathematical model which would quickly be easy to proven false by measurements or stability analysis.) But neither of those avenues is open to them when they walk into a classroom and the teacher asks them to “explain this phenomenon.”
I think the students would quite happily agree that they haven’t given an explanation which is good by any sane measure—it’s quite likely that many of them would also agree that they don’t actually believe their explanations. But I wouldn’t agree that they’re being irrational in stating them.
Everyone agrees that the physics students are just doing what they’ve been incentivized to do in class after class. It’s just worth pointing out that the behavior they’ve been trained to do is not at all like doing science, and that nobody seems to know or worry about this.
“Eh, maybe because of the heat conduction and so?”
should give you at least 1⁄3 of a point, after all, one side of the plate is hot :)
This is exactly the sort of mistake that Guessing the Teacher’s Password was written to disabuse. The answer demonstrates no understanding of the phenomenon.
Upvoted. Heat conduction is involved in the true answer. The student has demonstrated that he at least knows where to start thinking about the question. I’d have more respect for someone who said ‘heat conduction’, or for that matter ‘caloric flow’,and tried to work out how that might work than someone who said ‘fairies’. Given that this is a question from a physics teacher, you’re not wrong to try to find physics explanations before you go to ‘trickery’, which is exactly the sort of ‘explain everything’ hypothesis that we’re nervous of.