Question: Levitation — floating in midair as if by turning off gravity — sure looks like fun in magic shows. Is it true a real frog has been levitated? And if a frog, why not you?
Answer: To the world's amazement, researchers at the Nijmegen High Field Magnet Laboratory in Holland did manage to suspend a frog in midair with a balancing force of magnetism, as close perhaps as we'll get to a sci-fi anti-gravity machine, they said. The key is diamagnetism, a quantum phenomenon by which it turns out everything from wood to pizza to "frogs and even humans can be lifted by a magnet — providing it is strong enough," says Roger Highfield in "The Science of Harry Potter: How Magic Really Works."
All the billions of electrically charged atoms within, moving rapidly about and generating magnetic fields, make a body levitatable. "When the little frog underwent this form of levitation it looked comfortable inside the magnet and later happily rejoined its fellow frogs in the laboratory." A hamster too was levitated; and a human spent several hours (nonlevitating) inside the magnet without harm.
To levitate the frog required a field 100,000 times the Earth's magnetic field; a human would need a vast magnet and field many times stronger than an MRI scanner. And adds Sir Michael Berry, wizard of quantum mechanics, since the body is not uniform — tissues, bones, etc. have different magnetic properties — we would feel pushings and pullings all over. "If the magnetic force on flesh is greater than on bone, it would be as though we were held up by our flesh, bones hanging down, a bizarre reversal of the usual and possibly the basis for an expensive type of face-lift."
Still, concludes Berry, "I would enthusiastically volunteer to be the first human levitatee." You, too?
Question: In Edouard Manet's famous painting "A Bar at the Folies-Bergere," what subtle mirror unnaturalness helps lend allure to the scene? (See artofeurope.com/manet)
Answer: Part of the appeal lies in the contrast between the audience ready for entertainment seen in the mirror behind the bartender and her looking straight ahead, eyes betraying fatigue, say David Halliday et al. in "Fundamentals of Physics Extended: 5th Edition."
But as she looks toward "you" the viewer, there is something wrong: her back-of-the-head reflection is offset toward a side view even though the mirror is directly behind her (in reality her image should be eclipsed by her body). This places the reflection of the tophatted, mustachioed gentleman talking with her looking also out toward you. But if he's right in front of her as seen in the glass, and you're looking directly at her, then HE MUST BE YOU! "You are looking into Manet's work and seeing your reflection off to your right. The effect is eerie because it is not what we expect from a painting or a mirror."
Question: Frequently curious flyers, do you know what airport runway 9 signifies, 9L alongside 9R, whether a plane generally takes off with or into any wind, how the cabin is heated to compensate for the frigid air at 6 miles altitude, and the color of the "little black box" recording data in case of a crash?
Answer: Answers Ira Flatow in "Rainbows, Curve Balls and Other Wonders of the Natural World Explained": Runway 9 goes off at 90 degrees from North compass direction, or East; runway 27 goes off at 270 degrees, or West; 9L and 9R both go East left and right of each other; takeoff is into the wind to reduce required groundspeed and runway distance; no cabin heating is required but cooling via air conditioners certainly is or the pressurizing air coming off the engine would cook the interior; and the little black box is really orange for ready visibility amid tragic rubble.
So now you know and know and know. . . .
Send STRANGE questions to brothers Bill and Rich at strangetrue@compuserve.com