Oil and water: Ben discovers the secret


 Q. What trick did U.S. statesman and kite-flying scientist Ben Franklin use to still turbulent streams with a wave of his walking stick? –T. Jefferson

 A. In 1757, sailing with a fleet near Nova Scotia, he noticed that two of the ships had smooth wakes, the rest were ruffled by the wind, says Walter Gratzer in Eurekas and Euphorias: The Oxford Book of Scientific Anecdotes.

From the captain, he learned the cooks had been "emptying their greasy water through the scuppers, which has greased the sides of those ships a little."

Franklin doubted this, but in London on a day of strong winds and rough waves on a large pond, he tried an experiment, dropping a little oil on the water. Nothing happened. Realizing he had applied the oil on the pond's leeward side where the waves drove the oil back to shore, he tried the windward side. Though no more than a teaspoonful, the oil formed a thin film that spread and calmed a quarter of the pond, rendering it "smooth as a looking glass."

Now, whenever in the country, Franklin contrived to carry oil in the hollow of his bamboo cane, "magically" stilling turbulent streams as opportunities (audiences) presented themselves.

Q. It's roughly tantamount to falling 20-stories out of the sky, accelerating to 75 mph and thumbing your nose at the onrushing Earth (and living to brag about it). You're aboard "the incredible scream machine." What's coming next? –M. Hingeley

A. At the last split second, the roller coaster track curve pulls you up and jolts you with about 3.5 G-forces of deceleration, close to the gravity load– briefly!– of shuttle astronauts going into orbit (at 150 pounds you'll "weigh" 525), says Cleveland State University's Jearl Walker in Flying Circus of Physics, With Answers.

Top speed occurs early out of the gate, usually on the first long hill, though scarifying later features such as corkscrew curves and seeming low-hanging girders ahead may make speeds appear far greater.

Gravity's your sole propellant, so once your 14-ton chariot has been dragged to the first tiptop via electric chain contraption, the rest is downhill, energy-wise. Subsequent diminishing peaks are akin to a bouncing ball losing energy as it goes.

Tips: For maximum speeds, ride a packed train on a hot day– wheel lubricants become slicker, says Walker. Riding in front gives a sharper sense of plunging over a cliff at hillcrest (no visual forewarning). The caboose, by contrast, is the last car over and so has already picked up a lot of steam, hence you'll feel a force as if being catapulted up and out of your seat– "negative G's" to rabid rollerites.

Yet statistics show a coaster is safer than a car or plane-about 1 fatality per 250 million rides a year.

Q. Setting aside all the myriad ethical objections, could chimpanzees and humans successfully interbreed? –J. Goodall

A. No one knows– or if they do, they're keeping it to themselves, says Dr. Ian York of the University of Massachusetts Medical Center. Let's start with a relatively simple question: Can humans and chimps interbreed to produce fertile offspring? The answer is a pretty clear "No"; chimps and humans have different numbers of chromosomes (humans 23 pairs, chimps 24), which almost (not completely) means any hypothetical offspring would be sterile.

Members of different species can, in fact, sometimes interbreed. The most obvious examples are horses and donkeys, which are different species, have different chromosome numbers, but can interbreed like nobody's business to produce mules or hinnies.

Beyond this, though, says Dr. York, there's no simple rule for determining which species can interbreed. Humans and chimps diverged at roughly the same time as did horses and donkeys (between 5 and 10 million years ago), and very roughly they are about as similar, genetically, as are horses and donkeys. But that doesn't guarantee anything; it's a case-by-case matter. Some species which are more similar than humans and chimps cannot interbreed.

"In principle, it's entirely possible chimps and humans can interbreed. In principle, it's entirely possible that they can't. Unless the experiment is done, we won't know."

Q. Are patients who complain of intestinal gas really big producers of it? –J. Carrey

A. Many generate no more than average but are hypersensitive, reports The Merck Manual of Diagnosis and

Therapy, 16th Edition. Normal for a young man is 9 to 21 "passages" daily, and many patients fall in this range. On the other hand, one person clocked 141/day, including 70 in a 4-hour period. "Hence, objectively recording flatus frequency should be the first step in evaluating a complaint of excessive flatulence."

Gas episodes have been informally typed as the "slider" (crowded elevator), "pooh" (open sphincter), "drumbeat" (passed in privacy), and "bark" (halts conversation).

Odor profile traces to diet, bacteria, and gas type, adds Margaret McDonald in the Textbook of Gastrointestinal Disease. "If you're a methane producer, your stools will float... Better the relatively odorless methane than hydrogen-sulfide (rotten eggs)." Another feature of methane is that it burns with a blue flame, a fact employed by college kids who light up to become flame-throwing champs.

Send Strange questions to brothers Bill and Rich at strangetrue@compuserve.com.