The Four Minute Drill

My class is preparing for the second trimester exam.  Even though I provide an equation sheet on the exam itself, I still think it important for everyone to know the relevant equations cold. Without such knowledge, students approach tests as a game of "find the equation with a Q in it."  [See this post for some detailed analysis of how to use an equation sheet properly and improperly.]

My philosophy about memorizing equations relies heavily on, of all things, my seventh grade civics class.  Nowadays I couldn't tell you offhand who the governor of Virginia is, or who sits on my local county board of supervisors.*  But in 1985-86, I was the nearest thing to expert about Northern Kentucky and national politics.  I knew who Paul Simon was before he ran for president.  I knew that Kenton County's highest governmental position was called the "Judge-Executive."  And I still know these things... As we drove through Louisville over the summer on the "Gene Snyder freeway," I began singing Congressman Snyder's radio jingle while I explained to Burrito Girl why his district encompassed BOTH northern Louisville AND suburban Cincinnati.*

*Or if Madison County, Virginia even has a board of supervisors.

* Burrito Girl is my wife and sidekick.  As is so often true of my explanations, she didn't care.

Why did I, and do I still, know about civics?  Because Keen Babbage taught middle school civics at my school in 1985.  He didn't care that, even in pre-internet days, it was child's play to look up facts about local and national government.  In his opinion, all educated citizens knew off the top of their heads the length of term for a US senator.  And so, he made us learn these things.

Keen's crowning technique was the "4 minute drill," which I have adapted to physics.  He placed a list of civics facts on his podium.  He asked a question of each member of the class in turn; upon a correct response, the class earned a point, and he moved on to ask a new question of the next student.  If that student didn't know the answer, he could say "pass," and the question passed to the next student.  

Fast forward a quarter century.  My class takes "fundamentals quizzes" regularly.  But quizzes aren't always enough incentive to memorize facts; furthermore, even those who study diligently don't necessarily study effectively.  I use the "4 minute drill" to ensure that everyone at least learns their equations.

About twice a week, I run a 4 minute drill using the equation sheet.  I prompt something like "Force of friction;" the student has to say, "mu times normal force."  I only allow each individual to pass twice per drill; if someone has to pass a third time, we sit there awkwardly until he either gets it right, or until the 4 minutes are over.  We always run through the equations in the same order, so that we get farther and farther into the sheet over the course of a few weeks.  

At the end of each drill, I write the class's score on the board.  The sections of the same course compete with each other.  Sure, I offer a wee bit of extra credit to the class with the highest score in the marking period, but they compete for pride.

If you'd like to try the 4-minute drill, get a copy of my 5 Steps to a 5 prep book.  In an appendix, I list the verbal prompt I use for each equation on the AP physics equation sheets.  You can easily run the drill by just reading each prompt in turn.  And if you're not teaching AP, that's okay -- just pick the equations you've covered and skip the rest.

Review / Prep Books for Physics C?

Good texts are available
for physics C...

Back in September I reviewed the AP B supplement to the Walker 4th edition text.  The one sentence summary:  author Connie Wells, formerly on the AP test development committee, did a great job.

That post has now spawned two official comments and some informal inquiry as to what good Physics C supplements are out there.  I should have tackled this question before, but I'll go at it now.

Problem is, the whole idea of a "good physics C supplement" doesn't make complete sense to me.  

In Physics B or Honors Physics or Regents Physics, novice students are covering only the basics of a variety of introductory physics topics.  Textbooks are not wholly satisfying in such courses, because they cover way more material and depth than is level- or exam-appropriate.  Especially for the Regents level, the available textbooks are such compromises of committee writing that straightforward, targeted physics explanations are lost in the eduspeak.  So the purpose of a prep book at that level is for focus:  Here's what you need to know for this exam, here's a one paragraph (rather than four page) explanation of a concept in plain language, here are practice questions in the style of the exam you'll be facing at year's end.

In physics C, though, the textbooks are generally solid.  The mechanics chapters in Halliday and Resnick, or Tipler, or Serway, are all reasonably well correlated to the AP curriculum.*  The end-of-chapter questions vary from way easier to way harder than the actual AP exam, but it's not hard to pick out questions that are on-level, and even in a similar style to what is seen on the exam.

* Or, perhaps, the AP curriculum is reasonably well correlated to these common textbooks.  Chicken or egg?

Consider the typical student in physics C, and what he or she needs from a "review" for the exam.  This student has been in a class doing problems and reading a textbook all year.  A prep book is useless if it just mirrors the explanations and problems found in a text.

The strength of a good prep book is concise, focused, readable, non-mathematical explanations of basic physics concepts.  Books at the sub-physics C level already do this.  My own 5 Steps to a 5 book, the out-of-print AP prep book written for Kaplan by Hugh Henderson and Connie Wells*, Connie's supplement to the Walker book that I link above... all provide explanations of the basic physics at a readable level, along with straightforward questions and problems.  And when students are doing last-minute review before a major examination, straightforward and readable is the key.  Most texts do NOT do a great job with the basics.


*NOT the current edition of the Kaplan book


However, if two days before the exam someone's looking for a detailed discussion of solving something deep, like a Biot-Savart problem with a non-uniform magnetic field, a prep book isn't going to help!  The more mathematically intense problem solving methods can only be learned through careful and repeated practice.  You want to get good at Biot-Savart two days before the exam?  Do 7 practice problems from a couple of textbooks.  No prep book necessary.

The available textbooks generally do an excellent job explaining the more difficult aspects of calculus based mechanics and E&M.  The problems available from Halliday & Resnick et al are generally better and more numerous than what prep book authors can come up with.  And released AP Physics C exams are so plentiful * that even the most diligent students can find enough practice to occupy them.

* The Physics B exam has changed significantly over the years, such that only the last two (2004 and 2009) released exams are truly representative of what students will see in May.  Physics C has not changed so much, such that the 1998 and even 1993, 1988, and 1984 multiple choice exams are still mostly solid.  Careful, 'cause calculators were allowed on some of those earlier exams, but usually the calculator wasn't necessary.


Thus, my recommendation for physics C exam prep is twofold: (1) Use a physics B-level prep book to confirm an understanding of the basics; and (2) Use the published textbooks and released exams for practice.

Don't neglect (1)... with limited study time leading up to the exam, students are generally making far better use of their time by reminding themselves of fundamentals rather than solving unusual and difficult problems, even though the difficult problems might seem sexier.  In exam review time, it's all about getting the most benefit for the time spent.  And that's why a B-level prep book is often just dandy for physics C students.

Nacho, Nacho Day... and trimester exam review

This is just a repost that answers several frequently asked questions:

(1) How do you help your students review for a major cumulative exam?
(2) Why does your email say "Nacho Man?"

The point is, extra credit and food provide significant incentive to bring students into the classroom during what otherwise would be wasted independent study time.  Once students are in the classroom working diligently on physics questions, learning is happening even if music, conversation, and nachos are happening simultaneously.

Check out this post.

Peter Chen, a student who is well-versed in video production, intends to create a "cooking show" style clip about Nacho Day in our physics department.  I'll post the link in a month or so.

GCJ

Don't neglect "review" for lower-level physics exams

Young fool... only now, at the end, do you understand.

Those of us who teach AP physics have gotten used providing an extended review for a difficult year-end cumulative exam.  Conversation with AP teachers indicates that anywhere from two to six weeks is generally reserved for review.

I understand that "review" is often a pejorative term.  In fact, I was advised years ago to avoid that term entirely, lest ignorant colleagues question my usefulness -- "He stops teaching six weeks before the exam to review, so why should the students bother to go to his class?  They should skip physics lab and come to AP history class, where we're still learning new material all the way until mid-May.  And we should give him hallway supervision duty because he's not teaching, anyway."

I renamed this segment of the year the "putting it all together" unit.  For that's what we're doing:  not merely reminding our students of topics we haven't explicitly covered since October, but showing how all topics interconnect.  A good physics problem integrates two or three disparate topics, asking students to make connections.  Only in April, after we've finally covered everything in isolation, can we truly show our students these connections.  Furthermore, students rarely learn a physics topic well the first time they see it.  The second and third time, though, techniques and concepts become old hat.  So correct pedagogy requires that we introduce projectile motion in September, and move on; we occasionally do a projectile motion problem as we introduce bernoulli's principle or parallel-plate electrostatics; and, most importantly, do a homework problem in April on projectiles again.

I'm not telling AP teachers anything they don't know already.  I'm posting this with regard to lower-level physics classes.

I disagree with the typical approach to tests and exams in a general-level physics course.  Tests in the second part of the year often explicitly exclude force and motion topics from the beginning.  (I find "unit tests" to be common, and also nearly useless as a teaching tool.)  Frequently, the "final exam" becomes merely an expanded unit test on the last couple of topics.  These are not authentic evaluations of physics skills!  If we want our students to remember physics, we must continue to require them to recall basic concepts, even from the kinematics we covered last September!

I move very slowly in general physics, certainly in comparison to AP.  That's all the more reason to make every test cumulative, like I do in AP.  Early in the year, this is not a problem.  As the year progresses, and force/motion topics were covered longer ago, I find it more critical to do substantial review before each test and before the final exam. 

Through the month of April, my regular class covered optics -- waves, light, snell's law, lenses, and mirrors.  On the test in late April, I explained that the multiple choice would be exclusively these topics, but the "justify your answer" and "open response" sections would be on topics distributed throughout the year.  As preparation, for two days before the test we worked on a 60-question multiple choice practice sheet.  I set the sheet up as a game: we worked in randomized pairs, where each pair was awarded points not just for getting questions right, but for getting the DIFFICULT questions right.*

*The exact scoring was one point for each correct answer, and one additional point for each other group that got that answer wrong. This provides a disincentive from the class all relying on a single student to distribute the answers.

In the event, students performed better on this test than they had all year.  Only one student out of 22 earned less than a B.

I just tried the same approach again for yesterday's test:  multiple choice focusing on astronomy and optics, with the rest of the test cumulative.  We did a similar review exercise.  This time, though, about a third of the groups didn't take the review as seriously; we performed well on the test, but not as well as before.  There was a reasonable correlation between scores on the review multiple choice exercise and on the test.

The final exam is coming up in two weeks.  I'm not covering any new material.  Instead, we will build an AM radio, and continue AP-style review of the year's work.  I want to encourage preparedness for the general physics cumulative final exam the same way I do for the AP exam.

Do you teach a general-level physics course?  Do you have any general physics review ideas?  Post them in the comments.  I just might try out your idea next week.

GCJ



eMail Time: How much review time for AP physics?

http://homestarrunner.com/

From Vance Hurst, who teaches at Colquitt County High School in Georgia, and who attended my AP summer institute at Kennesaw State University last summer:

I am sitting here planning out my course pace for the spring semester. My question for you is this: When do you try to finish all of the material that is covered on the AP exam and do you do a cumulative review for the AP test. If you do a review, how many weeks before the the exam do you start it.

Hey, Vance... good to hear from you. My goal each year is to finish new material by the first week or April. After that, it's all review.

My fabulous department chairman at Woodberry, Jim Reid, suggested to me years ago that I not advertise on my syllabus that I'm doing a month of "review." Administrators, colleagues, parents, and students might look askance at the idea of so much review. After all, if it's "just" review, it must not be particularly important, so students should be okay to miss class, so students shouldn't have to do much work during that time... and so on.

But we as physics teachers know that "review" is precisely how physics is internalized. Ask anyone who's been through a physics program -- the first time they see a topic, it's confusing. The second and especially the THIRD time that a physics concept is presented, it usually sticks. I set up my AP class deliberately such that students see every topic presented two or three times -- once in the normal course of the course, once integrated into a subsequent topic if possible, and once again during the April review.

Jim and I agreed to call this four-week portion of AP physics by a special name. I chose "Putting it all together." I emphasize to colleagues and students that this time is NOT merely a review. Instead, it is a time when we focus on how all the disparate topics we have covered in isolation fit together. We are integrating and consolidating our knowledge and problem solving skills. In practice, I'm assigning old AP problems as homework, giving tests and doing corrections, doing loads of fundamentals quizzes, and running fun games and events, such as the physics walk and clicker contests.

A review by any other name would smell as sweet... right?

GCJ

Multiple Choice appropriate for General Physics

For juniors and seniors, my school offers only two levels of physics that don't require a prerequisite:  AP physics B and General Physics.  I will have a number of students taking General Physics as a graduation requirement, so this course must be accessible to folks of all academic abilities.  My approach to General Physics has been to teach mechanics, waves, circuits, and optics to the AP-B standard.  The goal is that if my students could take the AP physics B exam, but strip out all of the topics that we haven't covered, they'd all pass.  That makes for a slow-moving but powerful course.  On my February exam, I do give a long set of AP free response questions, on which my students perform easily to passing standard.

I've already detailed the free response questions, most of which are at the AP level, that will be on this spring's final exam.  But I want to give a set of multiple choice questions as well.  Most of the multiple choice questions available in the physics universe are at the AP level.  Since I have not spent any time this year with the General class practicing the correct approach to multiple choice questions, and since they have not had multiple choice questions on any other test, and since I want the multiple choice to HELP their performance rather than to serve as an additional challenge... I need some straightforward multiple choice. 

Enter the National Science League.

The NSL is a shamelessly commercial organization which sells science (and math!) contests at all levels from elementary to high school.  Their business plan is sound -- create straightforward multiple choice tests annually, promote the tests as a national "contest," and get schools nationwide to open their wallets.  In return for a sum of money, the school gets the test itself, some certificates and medals, and recognition on the NSL website on which schools are ranked in each subject by the performance of their top 10 students.

I personally have no trouble with the commercialism.  The NSL is filling an open economic niche.  From a competitive standpoint, the "contest" is worthless:  the 40-question multiple choice physics test is written such that any AP student who misses even one should be flogged.  Commercially, though, that makes a lot of sense... more teachers will be willing to give the NSL contest, and thus pay money for it, if they know that their students will feel successful.  Nothing wrong with that.

I use the NSL physics contest not as a contest, but as a set of multiple choice questions uniquely suited to my general physics class.  By coincidence, the topics of the NSL questions align nicely with my own choices:  mainly mechanics; some waves, optics, and circuits.  There are always a few thermodynamics or electrostatics questions that I have to cut out, but usually at least 35 of the 40 questions are right in the General Physics wheelhouse.

As part of my final exam this year, I will give the 2010 NSL.  As an added benefit, I have a built-in review packet: for practice leading up to the final exam, I have given out a previous year's NSL.  My students are consistently missing no more than 3-6 questions out of nearly 40. 

GCJ