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Less Is More: Teaching Strategies for Limited Class Time
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by Greg Jacobs
Woodberry Forest School
Woodberry, Virginia
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| | Lisa: Look on the bright side, Dad. Did you know that the Chinese use the same word for "crisis" as they do for "opportunity"?
Homer: Yes. "Crisitunity."
-- The Simpsons
When I lead one-day AP workshops, the crisis on most teachers' minds is that of limited time. I hear sorrowful stories of class time being lost due to new schedules, pep rallies, and other nonacademic events. Considering the extensive breadth of the Physics B curriculum, it is not surprising that we bemoan every lost second of contact time.
Workshop participants also discuss students' use of time outside the classroom. Some AP Physics teachers successfully assign several hours of homework each night;1 and in principle, such expectations should not be unreasonable in a college-equivalent course. In practice, however, many of our students cannot or will not spend the same kind of time on physics as college freshmen can. The typical AP student's spare time is consumed with other difficult classes, extracurricular activities, and teenage social events. How can physics compete?
Less Is More
A counterintuitive approach, but one which has proved successful for me, has been to turn the crisis of not enough time into an opportunity to sharply focus my class. Several years ago I carefully reinvented my Physics B course so that I assigned substantially less work, and so I spent substantially less in-class time on each topic. At the same time, I heightened the level of student accountability for every element of the course. This "less is more" approach has resulted in improved AP Exam scores and skyrocketing physics enrollment.
In this article, I describe the specific elements of my course that are intended to make maximum use of the limited time that I have. I write in the first person to emphasize that while each of these techniques works well for me, I offer them merely as anecdotally successful. Some of these ideas may not work for you -- my personality, teaching style, and school atmosphere are different from yours. However, by picking and choosing from the ideas below, and by including some innovation of your own, you should be able to augment student satisfaction and performance, even with an insufficient schedule.
Effective Assignment of Problems
In redesigning my course, my goal was for students to do fewer homework problems, but to pay closer attention to each one. This approach has worked wonders. Students feel like they're not doing that much work compared to, say, calculus or biology; yet they do as well or better on the AP Physics Exam. Some hints about homework:
Choose problems for quality, not quantity. I now assign only one or two problems per night, but these are carefully selected. I try to make sure that problems cover material we have discussed in class, but without duplicating examples students have already seen. The assigned problems should also provoke interesting postmortem discussions. A particularly good problem might:
- Lend itself to multiple correct approaches, such as an incline situation that can be solved either using energy conservation or Newton's laws2
- Have an answer that allows a fascinating discussion of physical reasonability, such as finding the acceleration of an electron in a television to be on the order of 1015 m/s2 3
- Involve a familiar topic of interest to the students, such as a calculation of the lift provided by an 80 m2 airplane wing (and a discussion of what kind of plane might need this lift)4
Use the AP free-response questions as a guide for the appropriate difficulty level for homework. I've found it counterproductive to assign simplistic plug-and-chug problems -- strong students find them a waste of time, while weak students build false confidence in their ability. Similarly, extra-hard problems, even interesting ones, can cause a wave of frustration and hopelessness to spread through the class. By the end of the year, my students know exactly what kinds of problems to expect on the exam, because they've been working AP-style problems consistently all year. This is the kind of confidence to encourage.
Every question requires explanation. It seems that the strongest and the weakest students are most likely to give problem solving short shrift by cramming their work and answer into the corner of a page. I'm clear from day one that every problem needs a thorough presentation. Among other things, I require one full, unlined page of work per problem, including a discussion of the reasonability of the answer. Since students are only solving two problems per night, they should have plenty of time to explain their problem solving process in detail.
Grade something every night or two. If students are not regularly held accountable for their study, then the "less is more" approach deteriorates into merely "less." My goal is to grade one problem or quiz every night. At absolute minimum, it's useful just to flip through student work, to catch any egregious slackers (or to commend any particularly well-presented problem).
It is important that homework scores count somehow toward the course grade. In general, the more you grade, the more homework can be worth. (I make it 25 percent of my grade, though most teachers count it less.) But the important part is the score on each problem -- if students know you are looking carefully at what they turn in, they will put forth more effort, whatever your numerical grading system.
Require extra help. If your school has an "optional" extra help period before or after school, make use of it, but don't necessarily make it optional. I automatically require a session of any student who earns less than 40 percent of the points on a problem. Such a score indicates to me either that the student didn't understand the concepts underlying the problem, in which case it is important to get him up to speed before he falls too far behind, or the student just didn't put appropriate effort into the problem, in which case an extra help session gives her time to apply proper effort. Most importantly, though, assigning extra help sends a message to the class that you care about your students, and that you are serious about holding them accountable for nightly work. Every year these consultation sessions are packed for about two weeks; after that, I only have to see a few folks about once per week.
Don't use class time to do homework. If you finish lecture early, it is far more useful to dig out a quick multiple-choice question to use as a "check your neighbor" exercise than to give free time to start on homework.
Foster collaboration. Time spent outside of class discussing physics with peers is often as effective as face-to-face time with the instructor. I have created an email discussion group, to which I post assignments and occasional comments on the homework. Students can also post questions, stories, or comments.
Since I work at a boarding school, study groups form spontaneously in the dorms in the evenings; even at a day school, I was amazed at my students' enthusiasm for working together and their ingenuity in finding ways of getting their groups together. Thus, it's rarely necessary for the instructor to do more than shepherd the occasional loner into a study group.
Your role in student collaboration, then, is not in the forming of groups, but in encouraging groups to work together effectively. It's most important that no one rides on anyone else's coattails: for example, I require students to spend at least five minutes working alone on each problem before seeking assistance from anyone. Even if such a requirement is unworkable, simply grading the homework regularly is enough for you to spot the hangers-on. A quiet word in the offending student's (and his partners') ear, along with a low assignment score, is usually enough to improve the quality of collaboration.
 Focused Use of Class Time
Assessment as a Teaching Tool
The Resources Around You
1 See, for example, Michael McIntosh's sample syllabus in the College Board's AP Physics Teacher's Guide.
2 For example, chapter 6, problem 37, in Physics, 5th ed., by Douglas C. Giancoli.
3 For example, chapter 16, problem 38, in Giancoli.
4 For example, chapter 10, problem 40, in Giancoli.
Greg Jacobs teaches AP Physics B and C at Woodberry Forest School in central Virginia. He is a graduate of Haverford College, and has a master's degree in engineering from Northwestern University. When he is not teaching, Greg broadcasts Woodberry Forest varsity baseball games over the Internet; he is a reporter for STATS, Inc., covering baseball, basketball, and football; and he is a Reader and consultant for the College Board's AP Physics program. Greg lives on campus at Woodberry with his wife Shari and their son Milo Cebu.
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