Everyone who has been to college has, at some point, taken a class from a professor who didn’t seem to care. Probably, some of them did care deeply about the class, but didn’t know how to express it (in which case more teacher training would definitely help). However, that’s not true for all. A friend of mine has TAed for a professor who said outright that he had no interest in teaching an intro class, but that doing so was the price he paid for doing his research and teaching graduate classes.
I do understand this sentiment. Unlike some countries, where teaching intro-level classes is considered an honor, in America intro classes often seem to be taught by grad students, non-tenure-track faculty, and faculty who are new to the department and “paying their dues.” If a professor’s research interests lie in quantum physics, teaching basic projectile motion may seem like time that could be better spent advancing the knowledge of the field and teaching more advanced concepts to more advanced students. Let those with no research teach the intro classes. I don’t even necessarily disagree with that – I strongly support hiring teaching faculty, whose focus and attention is solely on teaching and not research.
That being said, even if the professor isn’t interested in the class, the students should never know that. That professor may be teaching a couple hundred students that semester, but that student will only have one Intro to Physics professor. To some, who will never take another physics class, that one professor is the face of the subject. If that face is uninterested and just “going through the motions,” then what is the student going to think? On the other hand, if the professor is passionate about sharing the subject with his/her students, it may convince the student to be interested, too. People’s lives are changed by passionate professors, and ideally, that’s the face every student should see.