<p>The 6H seminar didn’t used to exist - my freshman year ('99-'00) the sequence just included Physics 6, which is like 6H but not as hard and served the dual role of being the first course in the major sequence and “physics for poets”. This was an artifact of the requirement that departments teach a certain number of “primary distribution courses”, which were part of a distribution requirement that was abolished during my tenure at Swarthmore.</p>
<p>Physics majors routinely complained that 6 was too easy, so it turned into Physics 6H starting the year after mine, while Physics 6, while open to majors, now serves as a de facto physics for poets.</p>
<p>The department likes to open with relativity and quantum mechanics because they’re sexy, counterintuitive, fundamental, and teachable at the freshman level without classical mechanics or E&M. They don’t require much in the way of calculus, either, so the introductory mechanics course can be taught at a higher level rather than being geared towards students who are taking calculus simultaneously. Also, by starting with quantum mechanics in the first year, the students have four years of quantum mechanics if they take the optional seminar (115) on quantum optics in their senior year, which is a very strong preparation for graduate study.</p>
<p>Incidentallly, while I believe theoretically physics majors can take 3 and 4 instead of the 6, 7, 8 sequence, the reality is that 3 and 4 are for premeds and engineering majors and physics majors always take the 6/6H, 7, 8 sequence.</p>