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The Straight Dope



Wil Wheaton, in Stand by Me, posed a very interesting question. Mickey's a mouse, Donald's a duck, Pluto's a dog . . . what the hell was Goofy? Enclosed is a bribe--the largest I could afford. --Britt R., Seattle

A year-old Seattle Mariners ticket is your idea of a bribe? Christ, a current Mariners ticket isn't exactly a siren's call to my ears. Equally gauche is your failure to grasp cartoon conventions. For starters, Pluto isn't a dog, he's a dawg. So is Goofy. The difference is that Goofy is a human dawg, whereas Pluto is a dawg dawg (or dawg(2), if you're into the new math). You can tell a dawg dawg from a human because the dawg gets naked and walks on all fours and the human doesn't, though admittedly this isn't the acid test it used to be.

Educated people--leastways, educated people who've just chatted with the Disney archivists--know Goofy first appeared anonymously in "Mickey's Revue" (1932), looking essentially as he does today except older. In the wonderful way of cartoons, he then got younger, meanwhile adopting various aliases, including Dippy Dawg, Dippy the Goof, and Mr. Geef before settling on Goofy in "Orphans' Benefit" (1934). So if the guy has an identity crisis, it goes back a long way.

I sort of understand how an airplane wing works in terms of Bernoulli's principle (although I have only a vague idea why Bernoulli's principle is true). I know the wing is shaped to produce more air pressure on its lower surface than its upper surface and thus provide lift. If that's so, how can stunt planes fly upside down? --John Kirkpatrick, Park Forest, Illinois

Simplissimo, chief. Airplane lift is the result of two things: (1) the shape of the wing, which has to do with the Bernoulli principle, and (2) the angle at which the wing meets the wind, known as the "angle of attack." The most efficient wings make use of both factors, but in a pinch (or an air show) you can get by with just the latter.

The Bernoulli principle for now you're going to have to take on faith. Angle of attack is easier. You see a demonstration whenever you stick your palm out the window while driving down the highway: angle your palm upward and the wind forces your hand higher; angle your palm down and the wind forces your hand lower. Same with planes. When you're zipping down the runway during takeoff, the Bernoulli principle generates a certain amount of lift, but to get that last crucial boost you pull up the plane's nose. This increases the angle of attack on the wings, popping the metal-fatigued welds on your starboard engine and sending you into a flaming cartwheel of . . . whoops, wrong index card. Actually, increased angle of attack provides the lift needed to get you flying.

Generating lift is easier at cruising speed, so stunt pilots can flip the thing over and rely on high angle of attack alone to keep them in the air (i.e., they keep the nose up and the tail down). This isn't a very efficient way to fly, since increasing your angle of attack also increases your aerodynamic drag. For that reason stunt planes need low-drag wings, heavy-duty construction (so they won't disintegrate in midair), and powerful engines that won't conk out when they're upside down. But in principle it's a piece of cake.

What's the most efficient means of transportation? I heard bicycling uses less energy than driving or walking, but what about horseback riding? --Scott Haugh, Richmond, Virginia

Not even close. A human on a bike uses up about 0.1 food calories per mile per pound (combined weight of bike and rider). A horse uses three to four times as much; a car or a walking human uses five times as much; even a freaking salmon uses up 2 1/2 times as much. Cycling's so efficient because you've got the powerful leg muscles continuously pedaling a rotary crank while the rest of you is sitting down--an unbeatable combination. In fact, so far as we know, bike riding is the most efficient form of transportation in the universe, living or mechanical, with the exception of interplanetary space probes (which coast, of course). Something to think about next time you're in the market for some wheels.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.

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