[This post carries the "rant" label, so it is presumed that your mileage may vary. I never presume my own experience is universal. None of this post refers to AP Physics C.]
Since I began teaching Advanced Placement Physics B in 1986, I have strongly encouraged all my AP students to purchase and take the AP Physics exam each May.
For now, I am recommending that they do not.
As we know, AP Physics B has been re-imagined as AP Physics 1 and AP Physics 2. The old vision of AP Physics acting as a college equivalent was dispensed with in the redesign. AP Physics B (as well as content standards prevalent in the 2000s) were seen as too content-focused, and lacked emphasis on process. Not an unfair criticism, to be sure.
The newly redesigned AP Physics 1 and AP Physics 2 are ambitiously constructed, multi-layered visions of physics course utopia. They are Lamborghinis sent in to replace the Camaros that existed until now. College courses, for the most part, remain largely content-driven.
The vision of the AP course being a college equivalent has been abandoned. AP Physics 1 and AP Physics 2 are the best courses time, talent, and energy can buy. Meticulously crafted courses of physics perfection.
But as of now, it's beyond my budget. And beyond the budget of my highly capable students. It is very much in an experimental phase. Version 1.0 of a complex new machine that we have been asked to be the early adopters of.
There is evidence to suggest the nation's AP Physics 1 and 2 teachers and students failed to abruptly snap to The College Board's new vision. Scores between the 2014 AP Physics B administration and the 2015 AP Physics 1 and 2 administrations show a massive shift in the wrong direction.
In 2014, more than 60% of AP Physics B candidates passed the exam with a score of 3 or better. Of those, 34% passed with a 4 or 5 (over 15% were 5s).
In 2015, more than 60% of AP Physics 1 candidates failed to earn a score of 3 or better. Fewer than 20% of the candidates scored a 4 or 5 (only 4% were 5s).
It could be that America's physics students suddenly became less capable. But that's not likely. It's more likely that America's best and brightest physics students weren't prepared for the radically different new exam.
The College Board would argue that they provided extensive information on the newly designed courses. And indeed they have. Exhaustive, really.
But part of The New Vision is that there is no longer a blueprint for exactly what content is to be covered and in which amounts. Physics content mastery is no longer tested, it is now presumed. Instead of distributing questions across a well defined subject-matter topic list, questions are not cast across broadly-defined Big Ideas and Science Practices. Mastery of these can be assessed via questions that merely use physics content as the canvas upon which the Big Ideas and Science Practices are painted.
True mastery of the Big Ideas and Science Practices, via Learning Objectives and bits of Essential Knowledge, painted on the canvas of physics, demands a level of engagement I find to be unreasonable. Don't get me wrong, I'd love for my students to be single-mindedly focused on everything we do in physics: in class and beyond the classroom. But my students have other things going on in their lives that demand attention. Many, many other things, as is typical of highly capable, multi-talented college-bound students.
It is certainly The College Board's prerogative to offer a product for purchase as they see fit. But in my opinion, they got it wrong. My misgivings may well be mine, alone. But that's not the sense that I get when talking candidly to other AP Physics teachers. I assume some folks love the redesign. I trust they'll light me up in the comments because I have not talked to such folks in person.
Speaking only for myself, I would say The College Board did what most august bodies do when undergoing a revisioning process: they spent their time, talent, and energy creating a grand vision. With a multi-dimensional outline and hierarchy. A complex and ornate structure. They then committed that vision to a tome of well over 200 pages.
What would have been more useful to me is for them to have spent more time, talent, and energy developing valid practice items. Practice multiple choice, practice multi-correct, practice free response (all types). I am very much "an assessment guy," having served on AAPT's Editorial Exam board, California's Golden State Exam development team, and California's Content/Assessment Review Panel.
So my process is inductive rather than deductive. If you show me a large sample of assessment items, I can determine what your grand vision was. But if you show me your grand vision, I cannot figure out exactly what your assessment items will look like. Maybe others can deduce better than I can.
But I have yet to see a grand, sweeping process (including you, NGSS) that respects the value of assessment and released items. The spotlight is always shown upon The Vision. Pesky questions about assessment and released items are marginalized with responses such as, "We'll get to that later," "We don't have the budget for that," "The task of item development will be given to other people who are not part of the Blue Ribbon Visioning Panel".
AP Physics redesign advocates encourage teachers to participate in week-long AP training sessions, and I do not doubt that such trainings offer great value (assuming the time and money can be managed). I also know of someone who did the AP training and was left with the impression that rotation was a huge focal point for AP Physics 1. Workshops will always carry the biases of their instructors.
What's more, suppose a student does make a passing score on the redesigned exam. They've shown they can drive that Lamborghini with aplomb. As far as I know, colleges are no more likely to grant credit for the post-redesign exam than they were for the pre-redesign exam.
I'm already past TL;DR territory, so I'll wrap it up. For now, I cannot recommend my students pony up $100 to (most likely) end up on the wrong side of the cut points on an experimental exam. I'll do my very best to prepare them for the exam. But it's fair that they know the extent to which the odds are not in their favor.
With luck, there will be a time in the future by which a sufficient catalog of released items exists so that I feel comfortable that my students will be able to fare well on the AP1 or AP2 exam. But I have no reason to think released item development is a priority for The College Board. So I'll have to wait them out. I do not know how long it will take.
I do know of schools that are switching from AP1 and 2 to AP Physics C, and I know of colleagues who are looking for college credit alternatives to AP1 and AP2. I understand the motivations for these moves completely. To those who are delighted with the redesign, I wish only happiness and good cheer. And the hope that they realize their own experience is not universal.