teaching

Inquiry Stylee: Physics

April 10, 2010 Shawn Cornally

These are real student questions, and they are stabbing at the heart of physics with a flaming machete.

An astute few of you have noticed that I’m not a trained math teacher. Probably the part on the “About Me” page where it says, “masters in science ed” tipped you off. I’m endorsed to teach math in Iowa through cobbled course work in physics and computer science. So, I suppose the question bears asking, when is Cornally actually going to talk about teaching science?

I’ve been a little afraid to, honestly. I don’t really have a thing for science the way a science teacher is supposed to. I don’t read every issue of Scientific American waiting for the newest research about T. Rex’s defecation habits. I don’t flip out indignantly when movies “get it wrong.” What’s worse is that I kind of find popular science to be a bit boring, repetitive (i.e.: Every “Brief History of Time” rip-off), and even harmful (i.e.: Mythbusters).

When I entered University and began studying physics, I was the exact opposite of those I points just listed. I guess I just came to feel that Science has become a juggernaut of elitism, whose middling members feel a sort of attraction to the materialist priesthood — You’re about to hit your “Quack Alert!” button, hang on, I promise to get back to teaching — I am one of those middling members: I have done research in condensed matter, high energy, and plasma physics, but I never pursued a graduate degree in favor of becoming a more well-rounded teacher. I guess I got turned off by the attitudes of some of my peers that were very anti-anything other than science (e.g: religion, literature, pure math, etc…). What’s worse is that I was like that, and my high school teachers helped me get that way. (Not on purpose, I don’t think)

I love my students, not science. When I was given my dream assignment (Physics, Calculus, and Programming), I knew that I was lucky enough to be teaching three courses that I’m truly passionate and fairly well-informed about. You’ve heard a lot about calculus and programming. Here are the pillars that I’ve built my physics course upon:

1. Physics as a duality of experiment and theory
2. The necessity of inquiry-based methods
3. Motivation for mathematical methods
4. The nature of science as a descriptor not a generator (Quack Alert!)
5. Standards-Based Grading

Since this blog is part soap box and part lesson plan archive, I’m going to start detailing the insanity that happens in my physics room (circular saws, and interpretive dance, and fire alarms, oh my!); this post being the manifesto/introduction.

1. Physics as a Duality of Experiment and Theory:

Many physics classes center on mathematical theory. They present physics as set of concrete rules by which all objects are governed.  While this is true in general, it is not for Physics I. Indeed all things seem to obey a small set in wacky rules, but we as teachers begin teaching this from the very onset, when we know quite well that things are being simplified. As much as you and I love forcing kids to solve coupled systems of quadratic equations (I’m salivating!), in the end these equations rarely match experiment. What’s that? Experiments, you say?

Let’s talk labs, which in most cases are a bunch of counter-productive crap. Spend a whole pile of your district’s money in order to create conditions that are nearly unreproducible on Earth so that kids can “get” equations that are only true in deep space. Great. I’m glad the air-table puck conserved momentum, at least now I’ll be able to sleep sounder at night knowing that mystery has been solved. I know what you’re thinking: “Cornally, relax, these are just demonstrations of basic principles. We need to simplify things so that kids can work with the basic principles.” I wish this blog weren’t rated PG right now.

So what have I done to bridge this gap? In class, we spend probably a little less time than average discussing the mathematical side of physics. Solving coupled equations, resolving vectors, taking determinants, what have you. We spend much more time than average in the “lab” setting.

As a teacher, I haven’t written a “lab manual” yet. It’s even hard for me to type the letters. Labs are teacher-generated piles of hokum designed to guide students recipe-style towards some specific principle/answer. Too bad that the kids don’t care, and they just want to get through the directions as fast as possible so that they can go home.

My process begins with a grant. We may have just been discussing F=ma, as the students’ questions start to roll in. “Why do things seem to stick at first when you push them?” “How many people does it take to move a refrigerator?” These are real student questions, and they are also stabbing at the heart of physics with a flaming machete.

Yup, I found this on the Internet. Flaming. Machete. Awesome.

So I make them write a grant. Just the basics, but enough information to get “funded.” What are you going to change? What will you measure? How will you measure it? How many times will you repeat at each level? How do you know that your input is actually having an effect? This is how I control the insanity that is inquiry. No worksheet, no packet. Just a student-generated plan and a judicious approval mechanism. If I don’t like the experiment — if it doesn’t speak to closely enough to the concept at hand — then it’s back to the drawing board. If I do, then it’s probably time to get out the power tools.

This is the important part: At the end of a student’s investigation it comes time for what most people call “physics.” Secretly they’ve been doing physics the whole time, but we now attempt to fit our rigid, bookish, theories and laws onto their real data. This has more value than any two-stared problem from any end-of-chapter problem set. The process repeats, and sometimes iterates. It depends on how awesome the questions are. This is how I work in traditional content.

The students then teach each other, and for the most part they care. They don’t know what the other kids did. Each investigation illustrates a slightly different set of physical principles that I can then grab a hold of to treat more formally.

My goal here is to remove the sterility from physics. It does not have to be a predominantly notebook-based affair. The book is only half the story. How did these historical figures come up with these equations? Aren’t you sick of your students guessing which formula to use and trying anything to get an answer that’s meaningless to them?! It’s because they’ve never had the chance to make their own formulas. So, let them and help them do it. You won’t know the answer when they start, but trust yourself; you and your kids will discover physics in everything (or biology, or chemistry, or …). I promise that concrete examples of this process are to come.

2. The Necessity of Inquiry-Based Methods:

Number one pretty much addressed this already, but let me clarify. Inquiry is not just letting your students ask a few questions at Q&A time. Inquiry is not letting them pick between 2 or 3 labs that you designed. Inquiry is the act of you, the teacher, helping students to create real scientific investigations from their own questions. Your kids want to test something they saw on Mythbusters? You’re the experienced one, help them design an experiment that actually gets results instead of ratings.

This can be hard on teachers. The connections back to the prescribed curriculum can be knotted and indirect. This can make you uncomfortable, but you have to trust yourself. You’re the expert, and you’ll help the students analyze their data. If there’s some interesting physics there, take the time to teach about it when the students are presenting their investigations. This is the same as you lecturing, but done in context.

There’s a mountain-and-a-half of literature out there about inquiry. Some good, some bad. Just remember, if you want kids to rush through things and actively disconnect from curriculum, go ahead and Joseph Stalin your lab activities. If you want kids to connect and think critically, let things get a little messy.

3. Motivation for Mathematical Methods:

Here’s where the central theme of my blog shows up: Math is a way of thinking and a tool. It allows us to describe things and discover things that would normally have been left obscured. People don’t naturally do higher level math. Processes need to be motivated; there needs to be a reason to introduce a new technique, and that technique better be the best way to get an answer. I have my detractors here, but I’m willing to bet they spend more time in offices than standing in front of America’s youth.

Physics is the perfect motivator. Want to describe something’s motion? Perhaps its temperature? Will it move if I do this? Math is good for all of those. I don’t mean that you should give kids a hard problem from the book just because it’s seemingly tied to the real world and expect them to gleam the beauty of cross and dot products. They need to see it, feel it, and then realize that there’s no other way to do it.

Why the hockey sticks are high school physics problems so contrived? Mostly because kids at that age can’t do calculus. Inquiry projects notoriously involve curvy and complicated subjects that lend themselves to calculus-based physics. One investigation is enough to hammer this point home to a kid:

Student: Hey, doing an experiment this way requires some methods I don’t know yet, either I will learn them, or perhaps I could structure my next query so that I’ll be able to use the math tools I already have.

Both of those are fantastic things to learn!

Please read my posts on Calculus (link at the top) if you’d like to know more about motivation and math. I’m well aware that I’m young and not really all that ground-breaking. Part soap box, part lesson-plan repository, remember?

4. Descriptor vs. Generator:

This is going to get a little philosophical, and if that makes you uncomfortable, you might just want to skip to part 5. I’m having some serious second thoughts about writing this section for fear of none of you ever returning.

My masters degree is in science education, and specifically the history and philosophy of science. What I have seen in my peers and popular science literature over the past 50 years is a switch from a view of science as a descriptor to that of science as a generator. The language used gives it away.

These are quotes from magazines who I won’t cite because I don’t want to get sued:

• “…evolution gave them [birds] wings.”
• “Energy is what makes everything go, it is the driving force behind the universe.”
• “The Higgs-Boson is the God particle because it gives all other particles mass.”

Is this science the Descriptor or science the Generator? Generator indeed. This is not how things once were.

The Higgs-Boson doesn’t do crap. It’s a descriptor. It is an idea. It is a pile of math. It describes nicely how something works in a fine and predictable fashion. It did not set the rules, it is the rules. Similarly, energy doesn’t exist, it isn’t some man in the hills flipping switches when things want to fall. It’s a concept that helps us describe spontaneous physical processes.

This switch to generator-centered language is damaging to students. It gives them a false sense that science controls things. It also short changes the process of science. What other beautiful discipline adds a caveat that: when wrong and shown to be, please erase and rewrite. What a terrifying switch to: I run the show, and am the source of all things you see, study me enough and maybe you’ll be able to be a magician too!

Needless to say, in physics class we discuss science as a physical descriptor of processes for which math is the language. The apple does not do algebra before it falls, it just falls. Why this happens is not a question for physics; how this happens most certainly is.

I’m really sorry if this section has turned you off to my blog, especially if you’re a math teacher. I promise to keep writing about calculus, and eventually all of the other high school math courses.

Standards-Based Grading:

I love writing that. I love lamp. I love Standards-Based Grading. See the link at the top of the page for more information. SBG offers students incentive and an atmosphere that promote the retention and remediation of knowledge. This is ultra-important to physics. If you don’t get force, you’re pretty much sunk. If you can’t resolve a vector, there’s no hope for momentum. How can I just move on when kids don’t get things? How can I even give a grade on a skill that requires a previous skill that a student doesn’t have? The ubiquitous summative-obsessed system is horse-feathers, I tell you!

Standards-Based grading reports a student’s performance on every specific concept in your course instead of every specific assessment. Who cares what piece of paper a question was on. It told you about that kid’s ability with kinematics and unit conversion, so report those independently instead. I’m a broken record on this one, please peruse my blog if you want to know more about SBG. I sort of am developing an obsession.

So, What’s It All Mean, Basil?

My physics class is based on helping students design great investigations based on their questions that get at the physical principles that are a part of my curriculum. I teach the math along side great experimental procedure, and we attempt to connect the two. Sometimes we see a great match of theory to data, sometimes the discussion of the deviance is much more useful. Finally, I use SBG to indicate to students that I care more about what they know, than me getting to be a gate keeper.

Thanks for any comment in advance. I learn so much from all of you, and my students get better served, too.