Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, October 6, 1994 TAG: 9410100004
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: JOEL ACHENBACH
DATELINE: LENGTH: Long
A: What a sweet question. Too bad we have to ruin it with one of our technical, mechanistic answers. (``It's simply the ionization of hydrogen atoms, nothing more.'')
The Why staff has long noticed that sleeping babies inspire universal adoration. All babies are cute but sleeping babies are somehow entrancing, wondrous, painfully precious. Is there something about the baby's appearance while wrapped in the arms of Morpheus that is so remarkable, or is there something being triggered in our brain, some primal protectiveness instinct?
How much is this an instinct at all, versus a merely rational response to the sight of something so small and innocent achieving blissful sleep in a world of peril, pain and the wailing of the damned?
For help we turned to auxiliary Why staffer Robert Wright, one of the best science writers around and the author of the new book, ``The Moral Animal.'' Wright, who admits that he is basically Mr. Gene when it comes to these kinds of issues, said that maybe we're programmed to keep a close eye on sleeping babies since they are especially vulnerable at that moment, unable to cry and crawl away should peril approach in the form of, say, a tiger with a major craving for Bebe Du Jour.
``The sensation of, `Oh, they're so cute,' would be your genes saying you should be specially vigilant now, you should not stray far now,'' he said.
This might be a case where we are trying too hard to find a Darwinian explanation for something much simpler. When awake, babies have a tendency to be rather ... demanding, shall we say. OK, make that monstrous. They scream, whimper, whine, drool, spit, bite, and worse. Their eating habits are vile. Each child is its own EPA Superfund site.
But when they sleep ... with those trusting little faces ... they're just angels.
Awwwww ...
Q: Why do squirrels get zapped by power lines sometimes, but not other times?
A: At the risk of actually dispensing some responsible advice, we'd like first of all to encourage everyone to assume that power lines are unbelievably dangerous and that it's basically insane to allow them to run across our neighborhoods and directly to our houses. What follows is not a guide to How You Can Play With Power Lines And Live.
Power lines are insulated. The problem is, they're insulated by air. Air is a good insulator, just like rubber or porcelain. This means that power lines are usually naked and exposed as they run from pole to pole. Sometimes, in areas with lots of trees, a ``tree wire'' will have a thin plastic insulation, but that doesn't make the wire safe to touch. The lines to a home may have heavier plastic insulation, but you shouldn't mess with them either.
A squirrel can run across one of those lines because he's not touching anything else. The electrical current has no reason to divert itself through the squirrel's body. The squirrel isn't giving the current a shortcut anywhere. ``Short-circuits'' happen because an electrical current finds a better, faster route than the one it's supposed to be traveling.
But let's say a squirrel climbs up the utility pole and stands on top of the transformer. That's dangerous. The transformer is that can up there on the pole, just under the power lines. A 13,000-volt wire is going into the top of that can, then passing through lots of coils, such that the voltage is diminished to a couple of wires with a total of 220 to 240 volts. Those wires and a neutral ground wire lead to your home.
The squirrel can't get hurt if it just sits on the can. Nor is it necessarily dangerous for the squirrel to jump through the air and land on the high-voltage wire. The problem comes when the squirrel, while standing on the can, touches the wire. He thus bridges the gap and makes a short-circuit. He's toast.
The remarkable thing is that the power company has managed to put all these energized wires in our neighborhoods while at the same time keeping them from touching anything and keeping short-circuits to a minimum. For example, there's the little problem of the wire that goes into the transformer can. That wire can't touch the can, because the can is grounded. So instead the wire first passes through a porcelain ``bushing,'' which is maybe 8 inches tall or so, and then passes into the interior of the can. The bushing puts enough distance between the exposed wire and the can to prevent the electricity from ``arcing' across.
By law, the exterior parts of the electrical system, from the transformer to your fuse box, are grounded, meaning that these things have the same electrical potential as the earth. A wire from your fuse box may be connected to the pipes in your house, which lead into the ground of course, or the wire may be connected directly to a rod driven into the earth.
Now you may wonder how it is that utility company workers (``linemen'' as they used to be called) manage to work with these power lines. For one thing they wear rubber gloves that are rated to 20,000 volts. For another thing, they stand in a bucket that is on the end of a non-conducting fiberglass crane arm.
And finally, the utility company worker is extremely (dare we say) well-grounded in the principles of electricity.
This is not true of the Why staff. We eschew electricity completely. The Why bunker is powered by candles, solar energy, a water wheel for grinding our cornmeal, and, in moderate quantities, uranium 235.
Washington Post Writers Group
by CNB