Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, October 14, 1993 TAG: 9310130044
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: Joel Achenbach
DATELINE: LENGTH: Long
A: There's nothing more sensual and decadent than a long, leisurely, steamy soak in the tub, especially if you have both a propeller-powered plastic submarine and a sub-hunting, depth-charge-dropping surface vessel. The bad thing is that within about 10 minutes you start turning into Prune Person.
Here's the headline: Your fingers and toes don't shrivel, they expand. Your digits get larger when you take a bath. You literally gain weight.
What's happening is that the dead outer layer of your skin (the stratum corneum, for those of you who insist on everything in Latin; we hesitate to report that the stratum corneum is also known more informally as the "horny layer," because, we're told, it has horn-like characteristics) is being hydrated. When things get hydrated they expand, because the water molecules are wedging themselves in between the fibers or tissues. Your skin buckles and swells and folds in the same way that wall-to-wall carpeting would wrinkle if it got soaked.
You may have noticed that the "shriveling" of your flesh in the tub doesn't happen as much, or as severely, as it once did, back when you were a tike. The reason is that kids have more resilient skin. Their flesh expands more.
Or maybe you've just stopped bathing.
Speaking of which:
Q: Why is there so much noise when you put your head underwater in the bathtub?
A: You can try this experiment at home if you promise not to breathe down there.
Take the plunge and the first thing you'll notice is the sound of your washing machine throbbing down in the basement as it goes through the spin cycle; or maybe the hum of your refrigerator's compressor; or maybe just the amplified splashing of water in the tub. Why's it so noisy? Because the tub is like a giant hearing aid.
Water has more density than air, and puts more pressure on your eardrum (or on the little pocket of air right next to your eardrum). The water also conveys the vibrations of various machines in your house directly into your skull. Your skull becomes a resonant chamber. Some of those sounds you hear have the weird inside-the-head quality that you also experience with your own voice as it vibrates up from your throat.
The more important thing to realize is that water propagates sound much better and faster than air. Sound moves 7 to 8 times faster underwater than in the atmosphere. And it travels much farther. If you go outside on the street and shout, you will only be heard for a couple of blocks. But sound can travel for hundreds or thousands of miles underwater. In one astonishing experiment two years ago, scientists proved that a sound could travel more than 10,000 miles underwater, about halfway around the world.
The remarkable durability of sound underwater is due to several factors. For one thing, there's no wind underwater. Wind, and the chaotic motion of air molecules in general, has a drastic effect on sound (just try shouting into the wind sometime).
Also, as sound travels through the air, some of the energy is transformed into heat. The same thing happens underwater but to a far lesser degree, because water is a thousand times denser and the motion of the molecules isn't as dramatic or as sloppy as the sound wave passes.
One other thing: When you shout, the sound moves outward in all directions. But in the ocean, sound can be reflected by the surface above and by the thermocline below-that being the depth where the water suddenly and dramatically gets colder. You can feel the thermocline in a lake if you dive toward the bottom. You can also, come to think of it, hear distant motorboats when you're underwater, even if you can't hear them in the air.
Whales understand all this. We're told they can communicate across as much as 3,000 miles of ocean. If their signals don't get drowned out, as it were.
"With the advent of mechanically powered ships, the ocean has become noisy, and the ability of whales to keep track of each other has greatly diminished," says Robert Pinkel, an oceanographer at the University of California at San Diego. "We must have awesomely affected their social life."
So you can see why they must hate us. They can't hear anything. As if it wasn't bad enough that we kill them.
The Mailbag:
Ross B. of Washington asks, "Why is one door of a double door often locked?"
Dear Ross: We talked to the building supervisor at the Why Things Are Earth Bureau (informally known as "the Kennedy compound") and he said that it's a matter of hinges. All hinges don't wear out at the same speed. So if you've got a gimpy hinge, you have to lock the door, and then wait for the other hinge to become similarly gimpy, and then go out and buy two new hinges.
But we think there's probably an even better reason: Climate control. You know how some people worry about losing air conditioning or heat to the outside elements. Some people are entropy-obsessed. So a store owner or office manager will lock one half of a double door to prevent people from opening both sides simultaneously and Hoovering all that conditioned air into the outside world.
By the way, we talked to the fire inspectors around here and they said it is definitely illegal. Gotta keep both sides open, they say. So the next time you slam into a locked front door, you have our permission to make a citizen's arrest.
Washington Post Writers Group
by CNB