STRANGE BUT TRUE- Heavy headed: Does size matter in brains?


DRAWING BY DEBORAH DERR McCLINTOCK

Q. Pregnant women who crave pickles may unconsciously be trying to make up for a mineral deficiency. But how about pregnant women who eat dirt, clay, laundry starch, bags of ice, innertubes– real junk food? –J. Fariello

A. "Pica"– from the Latin word for magpie, a bird that eats anything and everything– is a poorly understood eating disorder of some pregnant women, young children, and people with emotional problems, says Robin Corbett, of East Carolina University's School of Nursing. These episodes need not be harmful, but pose obvious risks of toxicity or intestinal blockage from the indigestible masses.

Many pregnant women, following treatment for iron- deficiency anemia, have given up their pica; or childbirth may end it. Other causal factors may be stress, family folkways, or imitation of pets.

Q. The professor readies a pan of molten lead, measuring 740 F. on the industrial thermometer, then prepares to plunge in a finger. What's he trying to prove? –E. Scissorhands

A. It's Jearl Walker of Cleveland State University doing another wacky physics demo, described in Fundamentals of Physics. He had read of 19th century carnival showmen dipping wet fingers into molten lead, and figured he was on to their secret:

"As soon as the performer's wet flesh touched the hot liquid metal, part of the water vaporized, coating the fingers with a vapor layer. If the dip was brief, the flesh would not be heated significantly."

So Walker wetted a finger and took the plunge. 

"Amazingly, I felt no heat," he says.

The water had indeed vaporized to form a protective sheath. Growing bolder, he wetted and dipped in all the fingers of one hand, deep enough to touch the pan bottom. "Still I questioned my explanation," he says. "Could I possibly touch the lead with a dry finger without suffering a burn? 

"Leaving aside all rational thought, I tried it, immediately realizing my folly when pain raced through the finger." 

Then he dipped in a dry wiener, which blackened within seconds, lacking also the vapor protection.

Never, never try this, Walker warns. A slight mistake can cause lead to solidify around the fingers, or send searing splashes onto the body. "I have been scarred on my arms and face from explosive vaporizations," he says.

Q. On an early space mission, astronauts went into mysterious sneezing fits. Were they allergic to the artificial air inside the capsule, or was the culprit aftershave, to which the cooped up riders were allergic? –J. Glenn

A. Neither. In the environment of weightlessness, myriad tiny hairs from electric shavers floated unseen about the cabin and into nasal passages and lungs, says Keith Lockett in Physics in the Real World. On subsequent flights, shavers were fitted with small vacuum cleaners to suck up whiskers. Conventional shaving cream and safety razor work even better, but a beard works best.

Q. If we Earthlings ever colonize the moon, what will the view of our home planet be like? –J. Frost

A. It would dominate the moon's night sky, with ever-changing cloud formations and phases, says astronomer Bob Berman. The moon from here looks enchantingly bright, but Earth viewed from the moon would appear near-blindingly brilliant, owing to Earth being four times bigger plus five times shinier.

This intensity would of course vary with the Earth's phase, which complements the moon's phase: "The slimmer the moon looks from here, the fatter and brighter our planet appears from there," Berman says. So on moonless Earth nights, there'd be full-Earth moon nights– and everybody there looking (if not behaving) a little crazy in their cool moonsuits.

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

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