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07 March 2012

I'm teaching ninth grade conceptual physics next year.

Yes, we will use the Hewitt
book for ninth grade
conceptual physics.
I've spent the last few years getting my school's upper level physics classes in shape.  I now have a skeleton of problem sets, quizzes, labs, and tests that my colleagues can use to teach 11th-12th grade general physics, honors physics, and AP physics B or C.  The general physics course is based loosely on the New York Regents curriculum; the honors physics course on my version of what a future AP physics 1 test might look like.

So now it's time to tackle the only level of physics that I've never taught (cue ominous music): Ninth Grade Conceptual Physics.

(As an aside, I *have* taught ninth grade.  Once.  My first year of teaching.  "Integrated Science."  At a fluffy school.  Team teaching with an idiot who denied the results of experiment, who undermined me to students and administrators at every opportunity.  The scars still give a wee twinge on rainy days.)

The juniors and seniors I've worked with for years enter the school year as reasonably mature students; it's been my job to provide them with a challenging course to which they can apply their well-developed study skills.  Upper level physics can almost be thought of as a master class -- here's where all of the math, organization, relationships with classmates, writing, all of everything you've ever done as a student must be used in combination to conquer a difficult but manageable subject.

I am well aware that ninth grade is a different boat of gravy altogether.  I've begun talking to some of my school's best ninth grade teachers, listening to their thoughts and ideas of how they structure their course, how they develop relationships with 14 year olds, what different types of issues I can expect once I start teaching an entirely new species.  

One overriding goal over the next two or three years is to develop my own version of a ninth grade conceptual physics course, complete with a course structure, problem sets, laboratory activities, quizzes, tests, etc.  In terms of the level of physics, I want to aim at a low-arithmetic adaption of Regents-style questions, as I explain in this post.  Some of the course structure ideas that I know I'm going to implement:

Pace of the course:  I need to invert my usual approach.  With seniors, I've got to shoehorn in as much material as possible in the first half of the year.  That's when they're still motivated by their grade, that's when they are still afraid that any slackage might lead to the world ending and having to go to (gulp!) a different college than their first choice.  In the spring, I get some work out of seniors by demanding less.  They feel like I'm legitimizing their senior slide, so they actually do the minimum amount of work that I ask of them without complaint.  Thus, I'm always pushing the pace in the fall, and tapering through the spring.

With freshmen, I recognize that the fall is NOT the time to push hard in physics.  Adjusting to high school, and in my case to boarding school, is a difficult process for an adolescent.  Sure, a few students are ready for serious academics from day one -- these folks will be siphoned into Honors Physics within a few weeks.  Most need a gentle introduction to high school.  Then, in February or so (just as the seniors start to slack), freshmen are ready to move fast.

Sequence of coverage:  It's been argued that a physics class can seem friendlier by starting with more straightforward topics like ray optics.  At the AP level, I completely disagree -- the last thing I want to do is to give the immediate impression that memorizing facts alone will lead to physics success.  I want to start tough and get easier.

But in ninth grade, we will start with ray optics.  Refraction, total internal reflection, lenses, and mirrors all can be taught well diagrammatically and conceptually, with absolutely no mathematics.  But, I can use Snell's Law and the thin lens equation as an "application" for the honors course -- students who *can* handle quantitative predictions with these equations can be moved out, while the remaining students learned some serious physics without feeling bowled over by mathematics.  

I haven't decided on a precise sequence of coverage, but I do know that we want to gradually add arithmetic and basic algebra as the year progresses.  By the end we will certainly have covered the "Big Three" skills of reasoning with equations, interpreting graphs, and understanding the meaning of numbers.  It's just that we'll get to these skills gradually, after we start with a topic that allows straightforward conceptual prediction and straightforward experimental verification.

Types of test questions: I talked extensively to Bruce Oldaker, who at one time was in charge of helping the physics department at West Point streamline their testing at all levels.  He put into words a point about test construction that I have always done by feel:

First consider the portion of a test that is essentially recall, asking students to state facts or solve simple problems in situations they've seen before.  Then consider the portion of the test that asks students to synthesize multiple concepts, to extend problem solving techniques to new situations.  By sorting test items into bins of "recall" and "synthesis," it's possible to control the perceived difficulty of the test while adjusting the rigor of the evaluation of the students' physics knowledge and ability.

Now, as a long-time AP teacher, I have always advocated (though I didn't say it this way) keeping the "recall" and "synthesis" portion of a test consistent throughout the year, and in similar proportion to what students will see on the cumulative national exam.    Sure, that makes the first test of the year seem difficult; but soon enough students are old pros at physics tests involving considerable synthesis.  The shock of a test that doesn't just present homework problems with the numbers changed is going to happen sometime in the year; so, I say, deal with the shock right away when the class has plenty of time to recover.

Freshmen, though, need to build up to "synthesis" testing gradually.  Bruce and some of my colleagues point out that the same students who can't do anything but spit back facts at the beginning of the year will often develop their reasoning skills so that they can handle difficult questions by June.  Freshmen are growing that much physically and intellectually.  So, Bruce suggests that early tests be as much as 80%-90% recall... and that by the end of the year the recall percentage can be reduced to 40%-60%.  Without wasting too much time on meta-analysis, I'm going to be conscious of starting simple, and adding complexity to my tests throughout the year.

Got any ideas?  I'd love to hear 'em.  I've got an enormous amount of work to do to develop the freshman course to my liking.  It will take several years, and it will take plenty of failed attempts, too.  Maybe in a couple of summers I can hold a "Conceptual Physics Summer Institute" where we all get together to talk about teaching freshmen...

GCJ



22 comments:

  1. My son and I tried reading Hewitt's book and found it so slow-moving and wordy that we gave up. The lack of math is compensated by having explanations be about 10 times as long as they need to be.

    You might be better off doing without a text, or finding one that does not put people to sleep before getting around to saying anything.

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    1. This is really interesting to read 2.5 years later... I agree, Kevin. After the first year I ditched the text in favor of "fact sheets." Hewitt is great for me to read, but it's way too wordy and unfocused for a 9th grader.

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  2. [This is from Dan Kittell, who could not get the comment function to work properly, so he emailed me:]

    I teach 9th grade physics & honors physics (still 9th) at a private school. Here's a few things I do for the general 9th grade physics course:

    * It's not 100% conceptual: so not really conceptual physics, but rather "Physics 1st," ie, before chem and bio. One benefit for this type of curriculum is for the students to see many of the math concepts in algebra and physics concurrently. Apply the concepts & skills in multiple contexts, etc. Math is certainly NOT a focus, like in honors or a JR/SR course, but it is there. Indep/dep variables, Sci meth, direct & inverse relationships. Slope interp, math modelling. Basic 2 and 3 variable equation solving (T=1/f, v=lamda*f)

     

    * For equation problems (using math) I enforce a process of problem solving where they must ID the given variables, the unknown variables, then what equation they need to use. Even for T=1/f I make them do this so focus on the process of problem solving.

     

    * IMO, your instinct to start with math-light physics like optics is spot-on. I begin with basic pendulum experiments for many reasons:

    - they get an understanding of what Freq & period actually MEAN

    - it's a great way to get kids IDing variables, what a good purpose, hypothesis and procedures are for lab experiments.

    - they can collect data to ID increasing and decreasing relationships and a "no relationship" data set.

    - understand inconsistent data and insignificant changes in data due to measurement error.

    - it's fundamental to understand T & F when we move to the next units: waves, sound & light.

    - T=1/f is the most simple equation in physics, having only 2 variables. They have to use fraction and reciprocals which are always lacking at the HS level, IMO.

     

    * after that, move to wave basics and wave types, introducing the wave equation for sound.

     

    * then move to physics of harmonics for open and closed tubes. the math is still no more complex than the wave equation, but understanding HOW MANY WAVES fit into an open/closed tube adds a SIGNIFICANT leap in problem solving with out adding complexity to the math. Plus, they can apply proportional reasoning and more fraction practice.

     

    * then move to Physics of light which is still no more complex mathematically (just wave equation still) but necessarily introduces Sci Notation and unit conversions b/c the freqs and wavelengths are so extreme.

     

    * move to a color unit on addition/subtraction of color (a bit of a breather from the math and the kids like the unit)

     

    * finally go to physics of reflection and refraction. as you said, all the math is still very basic here if you remove Snell's Law (which you must at this level).

     

    This is the entire 1st semester (Aug-Jan) and parts of the content are AP-level physics (lenses, mirrors, harmonics), but slower paced and of course the math-light AP content.

     

    By Jan, the kids should have a solid background with slope and linear relationships from their math course, and this is where I begin kinematics:

    1) graphing skills & const vel motion: introduce good qualities of graphs, how to graph by hand, slope:  it's units, it's meaning, y-int, it's units & meaning, and applying y=mx+b to become x=vt+x_0

    2) Accelerated motion: 1st w/o the math... lots of motion maps and qualitative graphing. then the math of accel motion. quadratic relationships.

    3)forces, force diagrams and newtons laws, equilib. friction is a great direct relation to interpret for this level of student

    4)momentum and energy conservation (no work)

    5)circuits & ohms law

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    1. Greg,

      I know you didn't write this comment, but I was wondering why Dan decided to take out work in the momentum and energy conservation topic. Work allows another level of reasoning where the students will have to make the decision between forces being used or the energy of the object being changed. This may just be because my students have trouble with multi-step problems.

      Also, I was wondering if you've completed your sequence of topics yet. I'm in the middle of planning mine and would love to compare. Thanks!

      -Jon

      P.S. Sorry for spamming this post earlier in the year, you can delete those :-P.

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    2. Jonathan, I'll hazard a guess: The textbook definition of work requires a dot product of vectors. At the AP level, I present that dot product simply as "multiply the distance by the component of the force parallel to the displacement," along with "work is negative if the force component is antiparallel to the the displacement, positive otherwise." That's a lot of stuff to remember and digest, but it beats trying to teach dot products.

      At the general junior-senior level, I simplify even more: Work is simply force times distance. I don't get into situations in which the force and displacement aren't on the same line. And, I finesse the sign of work by writing out conservation of energy in words, something like "(work done by rope) --> (potential energy of the crate)" or "(potential energy of the block) --> (kinetic energy of the block) + (work done on the block by friction)".

      Thing is, that's a lot of finesse. It could be that Dan finds it not worth the trouble to define work in a physically correct way, but one which allows manipulation by 9th graders; it could be that Dan finesses work within the confines of energy conservation, without using the term. Don't know.

      Haven't completed the sequence yet... thing is, I'll want to teach the course for a year before I say definitively what can be accomplished in a full year. I know I'm starting similarly but not identically to Dan: (1) Snell's law without Snell's law (but with n=c/v) , lenses and mirrors without the thin lens equation, basic wave motion with v=lambda*f, electric circuits; then mechanics.

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  3. Greg,

    I'm really excited that you're about to start on this arduous task of creating a 9th grade conceptual physics curriculum. I myself am a 2nd year physics teacher that is attempting to do the same, and I'm working myself to the bone without much collaboration (I'm the only physics teacher). I would love to see and hear more about what you're creating because my curriculum could use some help. The problem I keep running into is that I'm dealing with a population of students where their collective math skills are at an algebra level and not very good at that either. So, it's a constant struggle between trying to push a heavier math understanding of concepts as opposed to a super conceptual view. I look forward to seeing what you create!

    -Jon

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  4. Greg:

    The coasterman is wondering: Does the text give the name of the ride pictured on the front cover? I have a fairly confident guess but curious to see if I'm correct.

    - Justin

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  5. From Dan, via email:

    Dan finds it not worth the trouble to define work

    ^^^ this is essentially it. Certainly, the dot product approach is over their heads, and I think the "component parallel to displacement" approach is as well. Aside from those, what's left to understand about work?

    1) W=Fd (no cos(), no vectors: the students are concurrent with Alg1). A 3 term equation with little insightful physics, IMO. We already cover several 3-term relationships (DEATH to the circle, BTW).

    2) The energy-work relationship. I certainly could work work (HA!) into the energy unit. However, it really is just an application of energy conservation applied when you consider interactions outside the system. We certainly cover energy conservation, and I don't find the added rewards for the students to be worth the time it takes to discuss work as energy conservation. I'd love to cover it, but it's not worth the time, IMO.
    ******

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  6. UPDATE: I've taught my conceptual course for several years, and it's in good shape. We discussed it at the "Open Lab" in July 2014, and I'm willing to forward materials to anyone who's interested. We'll hold another open lab in 2015 where you can discuss this course with me in person.

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    1. Hi Greg,

      Do you still have materials to forward? I am teaching high school and conceptual physics for the 1st time this Fall. I am in the process of preparing my course and I am struggling to use the Hewitt book. I would be very interested in your fact sheets that you distribute instead of a book to see if that is something I could implement.

      Thanks! Sarah

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    2. Sarah, I have lots of materials, and I'm always happy to forward. Send me a direct email, and I'll give you whatever I can. Fact sheets are easy to send.

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    3. Hi Greg,

      I was also curious about the possibility of receiving some fact sheets or materials that you are open to sharing. I am a new teacher for the world of Physics and will be designing a 4 month (1 semester) conceptual physics course. Trying to decide what is realistic for such a short course.

      Any help would be appreciated.

      B.

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    4. B., always happy to send my course materials. Send an email with a U.S. Mail address, and I'll send a cd. Or come to my summer institutes...

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    5. Hi Greg! I would also love to get some information. I'll be a first year teacher this year and will be teaching some conceptual physics. I've just sent you an email as well I'd love to make it to one of your summer institutes, but I don't think that will be an option this summer.

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  7. I'm teaching 7th grade Physical Science at a TAG school in Portland, OR. Any recommendations on texts? I've found most Physical Science texts are too broad and vague. My students read at a ninth grade level and are very capable. Maybe two texts, on in chemistry and another for physics?

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    1. J, I'd go with fact sheets, not a text, ESPECIALLY at the 7th grade level. If you'll email me I'll send you the fact sheets I use for conceptual physics.

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  8. Dear Greg,
    I love your sequencing for the conceptual physics course and would like to implement it this year (my first year teaching conceptual physics).
    Would you mind emailing me the fact sheets that you use for conceptual physics? Also, any advice, suggestions, etc. would be greatly appreciated!
    Thank you so much!
    B.J.
    new conceptual physics teacher

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  9. Happy to... Please contact me via email. Thanks!

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  10. Hi Greg,
    My son will be taking 9th grade Conceptual Science at the same time as Algebra 1... in your opinion, do you think this will be overwhelming to not have completed Algebra 1 prior to CP ? Thanks

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  11. My son will be taking 9th grade CP at the same time as Algebra 1..do you think this will be overwhelming to not have taken this math prior to CP? Thanks

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  12. Crystal,
    Can't speak for every school. But most conceptual courses -- certainly mine -- assume no prior algebra skills. A properly taught physics course uses some basic math, but is emphatically not about math. I've had plenty of poor math students love my course, because it uses complementary skills to math, but is more interesting and meaningful to them. That's experimental work for you, I guess. :).

    Your son should do great. Good luck to him...

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  13. Hi Greg:

    I hope your blog is still functional. I love your sequencing for the Conceptual Physics course and would like to implement it this year also. Would you please send me the sequencing, materials, fact sheets and any other material you can share. This is my first year teaching Physics from the conceptual physics book and is afraid students will be bored stiff. Thank you for offering to share your work.

    G.C. H
    First Year Physics Teacher

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