Wednesday, August 24, 2005

As The Crow Flies


In my high school physics class we had one day where we were to learn about reading maps (um, it was not AP physics...)

So the teacher -- a sharp guy -- gives us this map of Southern California and has us read off various things. I do some measuring and, behold, it's forty miles from Glendale, CA (where I went to high school) to San Luis Obispo (where my grandparents lived).

Now, my family drove that trip fairly often, about 4 hours each way -- road signs saying something like 220 miles or so. Thus, something felt fishy about the map... So I go up to the teacher and point all this out, mention my personal experience travelling up the gorgeous Pacific Coast for long hours.

And the teacher says something like:
No. That's it. Forty miles. As the crow flies.

And he makes a little crow-flying-in-a-straight-line hand motion to illustrate.

So I retire to my seat thinking that might be plausible -- then a bit later it starts to sink in that it's only plausible if the crow flies through hyperspace or has been toking serious quantities of Melange, or something.

Anyway, it was probably one of the most valuable lessons of that class: not only can textbooks and class handouts be demonstrably wrong; but also, otherwise smart people will believe things that actual, real experience (and common sense) proves false, so long as those things are written down.

And, to finally bring this around to my contemporary point: maybe it's not so bad if students get taught Intelligent Design in high school science classes. Start cultivating that suspicion of authority early and maybe sell a few more Pink Floyd albums.

5 comments:

Alan Kellogg said...

You ever map out the route you took? Straight line I don't doubt there's only 40 miles between the two points. But when you have to go around obstacles the way there can get much longer.

Ask yourself this; did the road go there directly? Was the road absolutely straight the whole way?

Steve Peterson said...

Thanks for dropping by, Alan.

At first that's what I though -- but after a few minutes in my seat it occurred to me that the road, while not direct, didn't twists back and forth so much that it'd multiply the distance by a factor of 4 or 5. Really, no roads do that unless they're going up and down mountains -- again letting the stuff written down get in the way of common sense.

2 or 3 I would have believed, though it actually isn't even that much, just 156 miles straight-line distance:

http://www.ersys.com/usa/06/0668154/distance.htm

Another point is that the teacher had an excellent opportunity here to illustrate the scientific method. Sometimes we'll be faced with claims that are questionable -- in those cases we should question them, and that takes the form of trying to replicate and verify experiments. In this case, simply going to check the given map against other maps or other sources of information.

K.C. Baxter said...

"And the teacher says something like: No. That's it. Forty miles. As the crow flies. And he makes a little crow-flying-in-a-straight-line hand motion to illustrate."

Maybe this was his experience "driving."

I visited L.A. some seventeen years and when I would ask people how long it would take to drive from one place to another, they would invariably answer "twenty minutes." We would drove to five different places in Los Angeles and Orange County and each time took more than forty minutes with that famous L.A. traffic gnawing away at our brains and sanity.

After the third time it came to me that the brain shuts down as a defense mechanism and the mind perceives that the whole trip took "twenty minutes."

Steve Peterson said...

Thanks for dropping by K.C.

One thing about L.A. drivers is that only time on the freeway counts -- so if it takes 10 minutes to get to the freeway, 20 minutes on the freeway, then 10 minutes from freeway to final destination, that only counts as 20 minutes.

That said I'm shocked, SHOCKED, that people didn't relativize their travel time estimates to time of day.

K.C. Baxter said...

"One thing about L.A. drivers is that only time on the freeway counts -- so if it takes 10 minutes to get to the freeway, 20 minutes on the freeway, then 10 minutes from freeway to final destination, that only counts as 20 minutes.

That said I'm shocked, SHOCKED, that people didn't relativize their travel time estimates to time of day."

That explains it! Like a politician explaining his/her "miraculous" economic policy.