The first law before Sir Isaac

Sorry about the absence. Between moving, a PhyzVan failure, a workshop, moving, a wedding, and moving, the blog had to simmer.

When teaching the concepts and subtleties of inertia and Newton's first law, I like to include some information on the understanding of the first law before the time of Newton. So I include a few relevant historical references.

1. "The cessation of motion is due to the opposing force…. If there is no opposing force…the motion will never stop."

2. "It is impossible to say why a body that has been set in motion in a vacuum should ever come to rest; why, indeed, should it come to rest at one place rather than at another. As a consequence, it will either necessarily stay at rest or, if in motion, will move indefinitely unless some obstacle comes into collision with it."

Both references precede Newton's Principia by about 2000 years.

Reference 1 comes from the Mo Ching, published in China approximately 2400 years ago. The source of reference 2 is a little more shocking.

When posed to groups of physics education professionals, I've never had anyone correctly identify the source. Some guess Newton, others guess Galileo. And these are smart people--many of them much, much smarter than I'll ever be. I'm pretty sure many of them don't believe me when I tell them the source.

The point of the lesson is a fundamental truth stated eloquently by Alfred North Whitehead: "Everything of importance has been said before by someone who did not discover it."

I'm done with kinematics

When I started teaching high school physics (during the Reagan Administration), I felt an obligation to "reinvent the wheel." I didn't blindly follow the sequence of chapters laid out by whatever textbook the school had. I was in charge of the curriculum! I wrote my own handouts, homework, tests, etc.

But what I turned out was a pretty true reflection of the introductory college courses I had most recently finished. Mostly the same topics. Mostly the same sequence. It wasn't so different from the textbook's sequence.

I had a whole unit on vectors. It followed my robust unit on "preliminaries" (scientific notation and so on). After vectors was the Month of Kinematics. One-dimensional, two-dimensional; graphical and algebraic. Ticker-tapes, falling bodies, the monkey gun... what's not to love.

The trees were losing their leaves before any mention of Newton was made in my class.

But I noticed a few things. My students never thrilled to the lessons of kinematics as I did. It's difficult, abstract material if you go into deeply. It took the human intellect about 2000 years to figure this stuff out. And we start the year in physics with it. And the year usually ran out before we got to how rainbows work or why the sky is blue.

I was thinking about slimming down my kinematics coverage when I saw Paul Hewitt refer to kinematics as a "black hole" in a Physics Teacher editorial.

Now I speed through motion. I cover it as much as I think it needs to be covered, then move on. (Sorry about the puns, but I'm a physics teacher; we breathe puns the way most people breathe air.) Newton's name will be uttered into air that could be 100F here in Sacramento. The leaves are still green in New England.

There are other ways to handle the problem of not getting to rainbows. The original PSSC program started the year with optics, an approach that galvanized a following even after PSSC abandoned it.

My point is to go easy on kinematics in particular and mechanics in general. First-year high school physics students don't need it to that depth.

The first year I went with the slimmed down kinematics, I held my breath and wondered which part of the sky would fall down. When June rolled around, I noticed that the whole sky was still up. And my students knew why it was blue.

Where were the psychics on 9/10?

I know I appear to harp on the poor psychics more than they merit. But do I really? They continue to get thoroughly credulous coverage in the popular press. On Oprah. On Montell. On Larry King. On the Eleven O'Clock News. On The Medium! And so on. It seems to me that science teachers have an obligation to cast a little light into the demon-haunted world whenever they can. (If my students know KE=1/2mv^2 but call up the Psychic Friends to inquire about the future, have I done my job?)

So where were the psychics, clairvoyants, etc., on 9/10/01? Did the events of the next day not register on their radars? Was the attack not significant enough to carry psychic energy (or whatever) through the temporal aether to them?

With their vast abilities to "see" and "feel," how did they miss something so huge?

Are fabricated Nostradamus quatrains the best they can do? (After-the-fact, as is always the case with Notradamus.)

I'll pose the question--simply as a question to be pondered by anyone who doesn't see that "real psychic" is an oxymoron. I'll pose it in class. Not on 9/11. That day is reserved for other things. But it's a fair question on 9/12.

Where were the psychics on 9/10?

Quick Preso on the "Psychic Sketch"

The link below will take you to an interactive QuickTime presentation (export from Apple Keynote). It's slimmed down from the one I used in class to make it a quick download. The original included groovier transitions and build animations, and full audio for Gary Numan's "Cars."

Th!nk About It: Psychic Sketch

The presentation is done in the minimalist style that I prefer. It's all about the images. You can make up your own script based on the images. Mine went something like this

[Begin]
Title Page >
1. Who's this? >
Does this help? >
What do you think? >
Actually, it's supposed to be a sketch of him >
Good match? Bad match? >
2. News10 said this >
>
3. Here's a story from Denver >
>
4. And from New York >
5. I think this is a better match >
Gary Numan! >
Answer 3 of these 5 questions >
< > < >
> [End]

Physics Begins With an "M"

A friend recently wrote me a kind note about the "First Day of School" post. In my response, I recalled the role that John Jewett's Physics Begins With an "M" played in the formulation of my first-day lesson plan. Jewett's idea is to introduce each new unit/section/topic/chapter with a small set of "M's." The M's are Mysteries, Magic, and Myth. The intent is plant to seeds of curiosity in students' heads. Each of Jewett's entries has a setup statement or question, then a subsequent response/answer.

Mysteries might include "Why is the sky blue" or "How do magnets work" or "How might you survive if your parachute doesn't deploy." Magic might include "Watch a test tube 'disappear' when placed in cooking oil," or "Use ice to start a fire." Myths might include "Astronauts in space are weightless because they are beyond the earth's atmosphere," or "Cats can see in the dark," or "Power is the rate at which work is done," or "Absolute zero is the temperature at which all molecular motion ceases." As a teacher, you cobble a small set of M's relevant to the topic you're about to teach, and present it before launching into the unit. On the first day of school, I present a large set spanning topics for the whole year. All questions. No answers. But with the promise that all will be answered before the year is out.

Another way I've used the book is as a source of extra-credit or lab make-up projects. A student will select an M and take home a photocopy of the text question/statement and the response/answer. They must then translate the text into the language they are studying at school (French or Spanish at Rio Americano). Then the student creates a poster with the translated text, splashy graphics, and a translation of "Take Physics: Understand the Universe" in big letters at the bottom. I get the poster, and give it to the appropriate language teacher to see if the translation is OK, then ask them to hang the poster in their classroom. Instant advertising for the physics program! AND cross-curricular synergy (or paradigm-shift, or whatever the latest buzzword is).

Jewett's original title was published b y a company that did an excellent job of keeping the book a secret. It's now available as World of Physics: Mysteries, Magic, and Myth. Get it! You'll use it all year long.

Since I'm recommending a book and I'll never have a MySpace page, let me make a few recommendations in the area of pop culture.. First, go see Little Miss Sunshine. In a theater populated with other people. Don't wait to rent it. The crowd reactions are part of the fun. As for music, you should all be listening to Zero 7, Corinne Bailey Rae, Los Lonely Boys, and Leigh Nash. Don't let yourself get stuck in the 70s (Rick), 80s (Bryce), or even the 90s (Linsey). C'mon, peeps, move into the 2000s! (/mySpace)

Critical thinking lesson from current events

Sacramento's ABC affiliate followed a few other gullible media outlets in the recent frenzy of JonBenet Ramsey/John Mark Karr overcoverage. KXTV's news division found newsworthy this story of how a "psychic's" sketch drawn on the Leeza Gibbons Show in 1998 "bears striking resemblance" to suspect John Mark Karr. Internet forums were abuzz with comments like "spooky," "that makes me a believer."

In various accounts of this story, so-called psychic Dorothy Allison is given credit for having helped authorities with a manhunt for a serial killer in Colorado. The evidence of her help is notably absent, and research on the specifics of that case are notably devoid of any mention of Allison's help.

A sober viewing of the sketch reveals a decided lack of resemblance to Karr. The sketch looks much, much more like this shot of Adolph Hitler (sans mustache). Karr, on the other hand, looks much, much more like this shot of 1980s recording artist Gary Numan, who enjoyed success with the hit single "Cars."

The insidious part of such stories is that they credulously fortify the notion that psychics exist and that they have psychic powers. The sad reality is that much like Santa Claus and the Easter Bunny, "real psychics" don't exist. Nor do psychic powers. James Randi is keen to give anyone with such powers one million dollars. So far, the million dollars is safe and sound.

Now that Karr has been found to have no connection with JonBenet Ramsey (outside of his twisted mind), I'll wait quietly for the media outlets that ran with this bogus story to present their retractions.

But I won't hold my breath.

In the meantime, Joe Nickell has written a more enlightened account of this non-story.

"Planet Pluto" bites the dust

Beloit College releases an amusing list of "Things your freshmen don't know" every year. It's an attempt to keep againg teachers aware of the world that is familiar to students now entering college. This year's list includes items like, "Google has always been a verb." A previous list included, "The phrase 'you sound like a broken record' has no meaning to them."

In ten years, one item on the list will be, "Pluto has never been a planet."

http://news.yahoo.com/fc/science/astronomy_and_space

The first day of school

It's arguably the hardest day of the school year. You don't know your students and your students don't know you. Eventually, you'll all work your way into a comfortable rapport.

But not on the first day.

I struggled for about seven years before I figured out the first day of school. (And by "figure out," I mean that I came up with something I was happy with.) So here's my advice for the first day of school.

DON'T spend half the period mispronouncing your students' names. It's a time-kill and a first day of school buzz-kill. The students are fairly jazzed about returning to school, and there's a honeymoon going that first day. No need to squander it tripping over all those "tricky" names. You quickly transform yourself into the classroom dunce. It doesn't inspire confidence, doesn't really doesn't serve much of a purpose.

DON'T spend the entire period going over the class rules. What a way to crush the first day. You know those inservice meetings you're required to attend at the beginning of the school year--the ones you have before students show up? You know how they suck the life out of you before you even see your students for the first time. Yeah, it's like that, except now you're doing it to your students.

On the first day, students don't know how your class works. They have no context for your rules. How many classes do you suppose they have where they're NOT expected to be in their seats and ready for class when the tardy bell rings? Do you really need to pound that in on the first day? Let the class operate a little bit, and bring in the rules and policies as they become relevant.

DO cool stuff on the first day of school. Let your students know why your class is the grooviest class on campus. It is! You know that, but they don't know that. Don't keep it a secret. "Tease" them with hints and glimpses of the topics that will be covered during the year. Pose questions that you have no intention of answering until later in the year.

Induce curiosity.

When the end of the first day comes, they should jostle out of your room energetic with anticipation of what your class holds for tomorrow and for the rest of the year. They should be talking to each other about what you presented.

I would hold off on any kind of demo or activity that might intimidate students. That is, hold off on the counter-intuitive stuff. There will be time for that later. You don't need to make them "feel stupid" on the first day. Many are already intimidated being in a class called "physics." Don't scare them off on Day 1.

Have some fun on the first day. Get into your schtick! There will be time to learn the names and discuss the policies. Later. On Day 1, make them eager for Days 2 through 180. It's better for your students and it's better for you.

The Book of Phyz 2006

I have completed a fairly extensive update to The Book of Phyz online. Changes and corrections made during the past school year are reflected. That translates to many new documents and many more corrected (previously available) documents.

The update applies only to Physics 1. I hope to be able to complete a similar update for AP Physics 2 next year.

Many presentations were added as Zipped QuickTime exports of Keynote files. That means you can play them on your computer, but you can't edit them.

The Book of Phyz is an extensive collection of handouts, demonstrations, labs, worksheets, and other documents organized by topic and posted as PDFs.

Physics teachers are free to use Book of Phyz materials in their classes for instructional purposes.

What are the odds... [OT]

that I'd meet the brother of an old schoolmate whose children were taught by my best friend's wife at an Applebees in Gillette Wyoming? And all because I endeavored to snap this shot of stringy lightning at Devils Tower (60 mi from Gillette) earlier that same day.