College credit and placement for AP Physics C - take the credit, not the placement!

I've been reading an excellent discussion about different schools' philosophies about what to teach as a second year high school physics class after AP Physics 1.  I strongly prefer AP Physics 2; others prefer AP Physics C, especially as taught in the sequence described here. 

AP 2 is my preference because of the deep conceptual nature of the course.  Calculus-based physics is easy - yes, truly, I mean EASY - for anyone who has a serious and deep understanding of the underlying concepts.  And the high school environment is better than the college environment to develop conceptual understanding.  We can do things college professors can't - we have smaller classes, a closer relationship with our students, the ability to do hands-on laboratory work integrated with the entire course rather than in isolated weekly sessions; and we have the AP exam as a motivating and evaluative tool.

Those teachers who prefer to follow AP 1 with AP C are not wrong.  Students find value in approaching mechanics and E&M with calculus, especially during their senior year when it's important that the latter half of the course is easy.  They are learning skills that will serve them well in college.

But I see too many teachers and administrators making choices about AP courses for the wrong reasons.  

Specifically, a lot of amateur (and professional) college counselors see the words "calculus" and "algebra" and assume that physics C must be the better and harder course.  That's not true.  AP Physics 1 and 2 are much harder, and better as an introduction to physics.  A student with high level skills at physics 1 can pass physics C mechanics even with little or further preparation; that might also be true for AP physics 2 and C-E&M, but I don't have evidence.  There's a reason that I and many other experienced physics teachers recommend that even a Physics C E&M course begin with months of algebra-based material before ever touching the calculus.

Then there's the "colleges don't give credit" argument, which includes two major fallacies.

Firstly, don't believe anything you hear about college credit and placement policies unless you're talking directly to the registrar.  I've heard so many counterfactual rumors that I'm tempted to get Snopes involved.  People conflate placement with credit; people conflate credit toward a major with credit toward general requirements; people conflate different colleges with one another; people who should know better conflate the four current exams with each other and with old Physics B.  Be skeptical.

But more importantly... your students should most likely not be accepting placement out of calculus-based introductory physics, even if such placement is offered.  Okay, I'm not talking about a student trying to graduate early for whatever reason, or a student who needs to reach a certain level of work quickly to get a physics minor on their transcript or something like that.  I'm talking about the typical four-year college student who is considering a major in the physical sciences, and who needs to take upper-level physics as part of their course of study.

I've had numerous students over the years get 5s on both sections of the AP Physics C exams.  These folks are invariably offered the chance to start in the 200-level physics sequence as a freshman - usually a waves/optics course followed by introductory quantum mechanics.  I've had some students accept that placement; I've had others demure, preferring to begin in the standard 100-level introductory sequence that's essentially a fast moving AP Physics C course.

The feedback has never varied: the students who began in the 200-level sequence as a freshman all say they wish they had taken the 100-level introduction instead.  And those who started with the 100-level introduction were very happy with their decision.  

Remember, the 200-level waves/optics/quantum sequence is heavily mathematical, using linear algebra and differential equations fluently.  Even students who are comfortable with the calculus in AP Physics C will get lost applying matrix mechanics and differential equations to physical situations - especially when those physical situations have become even more abstract, even more removed from the laboratory experience and intuition they developed in your high school class. 

Furthermore, it's a difficult adjustment for a first-semester freshman to jump right in with sophomore physics majors.  Many freshmen have to figure out, well, life in general: how to live with a roommate, how to do laundry, how to handle the independence suddenly thrust upon them.  Even the most diligent and dedicated students often take time before they are back in the academic groove.  Trying to figure out quantum mechanics and the calculus-based wave propagation equation at the same time?  Um, difficult.  Survivable, sure, but perhaps a bridge too far.

Yet, those who take the 100-level Physics C equivalent become class leaders.  They have all reported (at many different universities) that the class still challenges them; they're not repeating already-learned material in a boring way.  Instead these veterans make friends among their classmates as they help out, figuring out new complexities in the process.  The relationships they build, and the confidence they develop in their skills, serves them well as they progress into the upper level courses.

And if they are mentally absent for a few weeks because they partied too much, or because they are dealing with personal crises as they learn to live on their own?  Well, they can catch up, because they know from your excellent high school tutelage how to learn the same mechanics and E&M topics they're faced with.