As of the 2025 AP exam revision, are Physics C mechanics and Physics C E&M two separate year long courses now? (No.)

On February 29 2024, the College Board released the course and exam descriptions for the revised version of all four AP Physics courses. You can find all the information and links at this page.  

For the AP Physics C exams, the course content will not change.  However, all AP physics exams - P1, P2, C-mechanics, and C-E&M - will be in an identical format as of the 2025 exams.  The format is, 80 minutes for 40 multiple choice questions; and 100 minutes for 4 free response questions.  That means an entire exam takes three hours.

But wait!  For decades, the two physics C courses have each had 90 minute exams, not three-hour exams, because the physics C courses have each represented a single-semester college course.  Has that changed?  

It has not.  Each of the FOUR courses now represents what is taught at the college level in a single semester.  AP Physics 1 represents the first semester of a college-level algebra-based introductory course.  AP C-E&M represents the second semester of a college-level calculus-based introductory course. And so on.

Thing is, we are teaching high school classes on a high school schedule.  The vast, vast majority of high school students taking physics for the first time should do a full year of mechanics.  This full year can be AP Physics 1; this can also be AP Physics C-mechanics for advanced students who are taking calculus.  Both cover substantially identical concepts.

For those taking a SECOND year of high level physics, well, AP Physics C-mechanics probably isn't challenging enough.  It's absolutely normal, acceptable, reasonable, typical for a student to take AP Physics 1 one year, then the combination of C-mechanics and C-E&M in their second year.  This post gives a recommended course sequence for such students.  

Me, I like to teach AP Physics 2 as my second-year high school course.  It's rich in diverse content, meaning that physics veterans won't ever say "oh, geez, not another cart on a ramp".  It's also particularly well adapted to seniors who need the course front-loaded - start with the hardest stuff like electricity and magnetism, and end with the simpler and more concrete topics like optics and thermodynamics.

But in any case, in any way you adapt the courses to your particular school ecosystem, the three-hour AP Physics C exams don't mean anything about how long you spend teaching the material.  Rather, the longer exams are a response to the fact that the pre-2025 APC exams were quite "speeded."  They were as much a test of how fast a student could do physics as how well a student could do physics.  And that's not what anyone wants to test.

Experimental procedures in AP physics, the redesigned free response section, and Wally the Astronaut

Wally the Astronaut, from The Physics Aviary

Above is a screenshot from the "Work to KE" simulated laboratory exercise on The Physics Aviary. In the exercise, you press start, and a fire extinguisher causes Wally the Astronaut to speed up.  You press stop, and the fire extinguisher ceases to apply a force.  Wally coasts, then passes through two photogates separated by 10 meters.  The time for Wally to cross the photogates is displayed.

You can do a thousand different sorts of classroom exercises with this single simulation.  I like to give this quiz here, go over the quiz, then have students go through this laboratory exercise. But the simulation here is so, so rich, you could do many different things.  Propose your favorite in the comments!

I was asked how I would describe* an experimental procedure on the AP physics 1 exam.  Some teachers ask their students to write a step-by-step instruction manual, including safety procedures and calculation instructions, for an in-class laboratory exercise.  Is that what the AP exam demands?  Should a procedure include calculational instructions?

*The "task verbs" on the AP physics exams will be in boldface as of the 2025 administration.

Historically, the AP readers expect students to communicate what they measured, and how they measured it.  If the experiment could in fact be done in a reasonable high school laboratory, the procedure is legit.  

The prompt on the AP exam - especially the redesigned 2025 AP exams - will be more targeted than what I often see in classroom lab handouts.  For example, the exam might write:

(a) Students are asked to take measurements to create a graph that could be used to determine the mass of Wally.  Describe an experimental procedure that the students could use to collect the data needed to determine Wally's mass. Include any steps necessary to reduce experimental uncertainty.

My response might be, "Measure the force F exerted by the fire extinguisher with a scale.  Then in each of many trials, turn off the fire extinguisher after Wally has traveled a distance d, a different distance in each trial.  Measure d; and divide the 10 m photogate distance by the time output of the photogate to find Wally's speed v."

The analysis - that is, how to do the necessary calculations - is usually in a separate lettered part of the question.  It's fine generally to write the analysis part in the same section as the procedure!  But the procedure will earn points independent of the analysis.  One being wrong or incomplete doesn't affect how the other will be scored.

Part (b) might ask about the analysis:

(b) Describe how the data collected in part (a) could be plotted to create a linear graph and how that graph would be analyzed to determine Wally's mass m.

And I'd say, "Wally's kinetic energy is equal to the work done by the fire extinguisher, .  [That first sentence is probably not necessary for credit!  But I write it so it's clear where my analysis comes from.]  Plot the work done by the fire extinguisher (Fd) on the vertical axis; plot (1/2)v^2 on the horizontal axis.  The slope will be Wally's mass."

Full credit would be earned for a more bare-bones "Plot Fd on the vertical axis, and v^2 on the horizontal.  The slope is (1/2)m."

A daily quiz based on 2023 AP Physics 1 question 1 - Did you *understand* how to do the homework problem?

It's getting toward the back half of the school year in AP Physics 1.  I've made a first pass at all the major content units; we've done laboratory activities out the wazoo.  We're gearing toward one more half-length practice AP exam before spring break, and then a final half-length practice in mid April.

My students need practice doing cumulative, AP-like problems which require synthesis of multiple concepts; or which require students to choose from the entire year's menu of possible approaches.  Later on, in April and May, I'll have students do authentic AP free response questions in class practically every day, without a safety net.  We're not quite ready to take the safety net away.

No, right now, I'm assigning AP-style free response questions as collaborative out-of-class work.  Everyone is encouraged to collaborate, to seek help when they're stuck.  As long as they get to the correct answers eventually, I'm happy that they're making progress.

You have questions about this approach.  "Even the most honest, diligent students will often just do what their smart friend told them to do, Greg.  Getting done with the assignment is more important than getting it done right.  Even with the five-foot rule religiously followed, at least some students are parroting, not learning, not progressing."  

Unless there's disincentive for pure parroting.  And I don't mean grade disincentive.

The approach I use - which is absolutely not the only effective approach! - this time of year is the daily quiz based on the AP-style problem.  When students come to class, I collect their assignment.  But the first four minutes of class are basic questions about the problem they did for homework.  We trade and grade the quiz, then I collect the quiz.  

Someone who understood the problem, even if they had to be nudged hard in the right direction, can do the quiz just fine.  Someone who truly parroted the smart kid cannot do the quiz.

Yet!  Even the student who parroted and then flunked the quiz has made progress!  The point of the quiz isn't to play gotcha, it's to review the problem in a context in which the students will listen.  If I say "Imma go over last night's homework," no one cares.  But if I say, "here's the answer to question 1 on the quiz and how I know, now mark your classmate's paper right or wrong," I get rapt attention.

My class is contract graded, which means there's no shame for poor performance, no cookie for being perfect.  What's the incentive, then, to take the assignment and quiz seriously?  If someone does particularly poorly on the quiz or problem set, I bring them in for a consultation to redo the quiz.  I just had a student in while I was writing this post.  It took him a relatively short time to redo the problem perfectly, with clear justifications for each part (including the parts that didn't initially require justification).  He didn't get this problem at first, but the combination of attempting it for homework, trying the quiz, and grading someone else's quiz meant that he gained a serious understanding of this problem.

Your ideas are intriguing to me, and I wish to subscribe to your newsletter.  Okay, here's issue 1: a quiz based on the 2023 AP Physics 1 exam problem 1.   Notice how the quiz gets to the essence of the solution without just asking "what was the answer".  This quiz brought forth excellent questions from the class about the physics behind the original question.  It made them think!

A cart oscillates, as shown above and on the problem set last night.

1. Point A on the graph is labeled in red.  On figure 1, draw and label where the cart is located at position A.

2. Point B on the graph is labeled in blue.  On figure 1, draw and label where the cart is located at position B.

3. How is frequency related to period?

4. What is the equation for the period of an object on a spring?

5. When a block is dropped on the cart, does the frequency of oscillation increase, decrease, or stay the same?

6. When a block is dropped on the cart, does the amplitude of oscillation increase, decrease, or stay the same?

7. When a block is dropped on the cart, does the maximum potential energy of the cart-block-spring system increase, decrease, or stay the same?

8. When a block is dropped on the cart, does the maximum kinetic energy of the cart-block-spring system increase, decrease, or stay the same?

9. When a block is dropped on the cart, does the maximum speed of the cart-block-spring system increase, decrease, or stay the same?