Timely discussion, as I am considering using your book for my statistical physics course next spring.
[OK ... not so timely any more. This has been sitting unfinished in my outbox for many months. Time to cut it loose. The question Dan had asked was, I believe, whether to make the solutions manual to his Thermal Physics textbook openly available online. This post, however, is not a direct response to that question, but rather, building on some of the questions it raised to pose another.]
I am very torn by this. My fist instinct is to beg you to keep it under lock and key, though of course as has been noted students with reasonably good google skills (or the wherewithal to pay Chegg) can find (some version of) them online with relative ease.
I certainly count myself among those instructors "pressed for time", as John Denker put it. I would be pleased to be able to put hours every week into the loving creation of homework problems and solutions never before seen by the likes of man, woman or beast -- but we all know that's unrealistic, for a whole variety of reasons both touched upon already and not so far mentioned.
This is an issue with every course I teach these days. I ask this question of every university-level instructor I meet when the subject of teaching comes up to see how they handle it. John D is correct that students have been seeking "outside" help since the dawn of time. I myself spent plenty of time in the physics stacks in the library (remember those?) as a student -- but boy, did I learn a lot doing it. It amounted to a whole lot of library research to find the clues that I needed, when I wasn't getting any traction all by myself. The problem we have now is that the bar to entry -- to find a solution to just exactly THAT problem -- is so very, very low, that the majority of students simply find what they need an move on. Some of them take the time to figure out what they're copying, but many simply do not. Usually, they don't even have to figure out how to adapt what they've found -- even the notation -- to the question they've been asked because it is THE solution to THE precise problem from THE course textbook.
I have learned through painful experience that (as I believe someone else has already noted), students are very, very incentive driven, in much the same way as modern corporate America: by which I mean, they respond -- very efficiently, too -- to the prospect of short-term gain over essentially everything else. For the majority, questions of ethics, what's best for their long-term learning and mastery of the subject, or pretty much any other consideration, all are simply irrelevant. Students will respond to what is directly (and immediately) rewarded. The future (even a midterm that's weeks away) is simply too distant to be much of a factor. And -- unless you are the ethically fussy type (yes, I'm being facetious) -- who can blame them (exactly...)?
If homework is a significant part of the grade, they will make sure they find good answers to the questions posed, by any means necessary.
If homework is NOT required (as in rewarded), the vast majority simply will not do it, whether or not it is important to "learn the material" or "do well on the tests". College students ALWAYS have something that IS due now, and IS being rewarded, to work or otherwise spend time on. They. simply. do. not. do. work. that. is. not. directly. incentivized. No amount of moralizing about whether this is "correct" behavior is going to change this.
So, what to do? Clearly, the plan is to find an incentive structure that aligns with the objective. My personal objective is provide a framework in which the majority of real-world college students will become familiar with the essential ideas of a subject and begin to master how to think in the way the subject demands. In other words, I want most of them to actually learn the subject at a developmentally appropriate level. So the question becomes, what incentive structure directly and immediately rewards what I actually desire, which is learning?
To be sure, I have been exploring a variety of models -- quizzes, more frequent exams, a number of other options. One unfortunate consequence of most of these types of alternatives is that they become a significant drain on class time available for other things (peer work, etc.) Options like quizzes also become quite challenging for advanced courses.
I'm getting closer to what seems to be a (better) working model. But I am still not satisfied, and would like to learn from others. So … I'd like to throw this one out there to see what bites. What are others doing to incentivize learning in the age of Chegg?