Thursday, May 1, 2008

Life Without Newton

It's bad enough that most Americans don't believe in Darwinian evolution. Far worse is that many of us - at least in daily practice - seem not to believe in Newtonian mechanics. This thought occurred to me today as I watched yet another car pull out directly in front of yet another fast-moving bus.

The driver of the car seemed in that moment not really to believe the First Law of Motion, to wit:
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

The more massive the object and the higher its velocity, the larger the force needed to slow it, stop it, or deflect it. In short, the bus is very unlikely to be able to stop in time.

More than this, when a very large, fast-moving object strikes a smaller, slow-moving object, which is the most likely to be - um - deflected from its current state of motion? It doesn't matter that the car in question was an SUV, except that its size relative to other cars may have lulled the driver into a false sense of invulnerability.

I gathered further evidence a short time later, on campus, walking up the hill on the way to my office. A student who was in my lecture class this semester, no doubt finished with his final exams, was flying down the street on his bicycle. At least, he seemed to think he was flying: he looked exultant. He was not wearing a helmet. I happen to know he is a very intelligent engineering student, no doubt about to graduate with some sort of honors from an engineering university of some prestige . . . but he seemed at that moment not to believe in the First Law of Motion. If some external force were to act on his bicycle . . .

I brought this up a few minutes later with one of my graduate student teaching assistants, who pointed out that people here in the South do not have sufficient respect for trains, whereas people from the Midwest know that long freight trains take a very, very long time to stop.

In this case, disbelief in the First Law is echoed and reinforced in children's books. My daughters have a picture book on their shelves in which a pickup truck, stuck on the railroad tracks, is saved by the frantic light-writing of a firefly. The driver of the train, apparently a few hundred yards down the track, sees the writing, sees the truck and stops the train in time.

I've heard that by the time the driver of a mile-long freight train traveling at 60 miles per hour can actually see an obstacle on the track, it's already too late to stop.

Don't even get me started on people who don't wear seat belts. The car stops, they remain in motion until . . .

I'm sure there's a subtle point to be made here about risk perception, self-deception, and so on, but I'm not going to go looking for it just now. I'll just end this by wondering aloud: What is it that allows some people to internalize Newtonian mechanics, to live as though mass and velocity have real, practical implications for moment-by-moment decisions, without special exemptions for SUVs? What would science education (or education in general) have to be like so that most people lived this way?

I'll add, as a post-script, a further question: What is it that allows some people to internalize Darwinian evolution, to actually live, moment by moment, in the world Darwin opened to us?

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