This time of year, many physics teachers, especially AP physics teachers, are preparing summer assignments for their upcoming classes to submit in the fall. While I understand the intended benefits of such assignments, I suggest that, in every circumstance I can think of, a summer assignment is a BAD IDEA.
First of all, imagine that your summer assignment will produce every possible benefit you imagine to the start of next year’s course. At what cost have you achieved these benefits?
Your students do not enjoy doing physics. Okay, maybe by the END of the course, some students will begin to see the intellectual attractiveness of physics. After all, one of the reasons we teach physics is in order to help students see the beauty in our subject. But in August, even the brightest 16-17 year olds in your class would rather be pursuing other wholesome and not-wholesome summer activities than doing your assignment. By requiring summer work, you begin the year with a hostile class: they come the first day with their assignment thinking, “Why’d you make us do this? It had better be worth it.”
Furthermore, even if your assignment is perfectly designed to produce maximum learning benefits, how many of your students will complete the assignment with appropriate care and attention to detail? It is far more likely that your students race to just get the dang thing done, minimizing any benefit they might receive through their effort.
For that matter, how many of your students will complete the assignment at all? A student who didn’t do the summer assignment has now forced you into an early test of wills. Either you make him do the assignment and take off substantial credit, setting yourself up from day one as a hostile entity; or, you give this student a mere slap on the wrist, showing your colors as a pushover whose assignments aren’t REALLY important. Why not save that fight for an assignment without a built-in excuse?
[I’ll make an aside here about enrollment rules. Depending on your school, AP enrollment might be set in stone in May, or might be still in flux all the way through August. If students are allowed to make decisions during the summer, then a summer assignment will reduce enrollment – AP physics is a much tougher sell if it includes a packet of stuff to do. And what about students who might be new to the school? A summer assignment deters them, too.
Thus, I can see one time when a summer assignment might be useful. If your course is oversubscribed with students of moderate talent but considerable feelings of entitlement – the “pushy parent” types – a straightforward summer assignment could be used as a filter. Students who are being pushed by mom and dad to take AP physics but who really don’t want to do the work (or who are not capable of doing the work) can use poor performance or lack of effort on the summer assignment as a reason to drop the course. I would not recommend this course of action except in extreme circumstances where you are in desperate need of a “weeding” mechanism.]
And finally, let’s look at that assumption of maximum learning benefits. If it is done carefully with attention to detail, what should a student expect to get out of a summer assignment? Most summer assignments I’ve seen have been heavy on the mathematics. Well, it’s been shown that math review in isolation does little good, and likely does harm. Math assignments give a false impression of what physics truly is about. Good math students become overconfident, then frustrated when they don’t pay attention to how to set up problems. Mediocre math students become frustrated right off the bat, even if they might become excellent physics students due to their conceptual understanding.
If not a math review, what would that summer assignment be? Are you going to ask students to learn kinematics or Newton’s Laws on their own? I wouldn't recommend that course of action, as the most likely result of such an attempt is that common misconceptions become further ingrained before you have a chance to address them in class.
My fundamental conclusion is that whatever positive impact a summer assignment might possibly have on next year’s course is not outweighed by the substantial cost incurred by requiring summer work.
Think of it this way. It is trendy for AP classes across disciplines to make summer assignments. History and English especially tend to load students with summer reading in order to get a head start on a difficult and broad course. And, your AP students are likely taking at least one or two of these other AP classes. Consider how much political capital and general goodwill you can generate by showing up on the first day of class saying, “Let’s learn some physics from the ground up” rather than, “All right, how many of you didn’t do your summer work?”
 in the classic Arons “How to Teach Physics” text, repeatedly in the physics teaching literature, through anecdotal evidence from good teachers, through my own experience…