STRANGE BUT TRUE- Sob story: Cutting the onion causes the tears


Q. Why are onions such tear-jerkers? Is it because of all the misinformation about them? –S. Dikkers

A. Misinformation, yes, such as that pyruvic acid is the lachrymator (tear-producer), that this comes from sulfur in the soil, that the same compound that gets to the eyes gives the onions their pungent flavor, that the really pungent ones are the culprits, or that the cook can minimize the problem by clamping a piece of bread or a match between the teeth, says Robert Wolke in What Einstein Told his Cook.

These last won't work, but chilling the onions in the refrigerator for a few hours before cutting them just might. This slows down the chemical reaction that produces the "tear gas"– a sulfur-containing compound called thiopropanal sulfoxide– and lowers its vapor pressure.

     Actually, the pungency compounds don't form until the onion cells are broken open by cutting or chewing. So it's best to use a sharp knife, dice the onion quickly and efficiently as the chefs do, and "there won't be time for the irritating vapors to bother your eyes very much," Wolke says.

Q. Where might you find the world's most expensive glasses of water, and who are the drinkers? –T. Frederick 

A. $3,000 per glass is roughly the price of fresh water ferried up to the International Space Station, says Hazel Muir in New Scientist. Each astronaut uses about 4.4 liters a day for drinking, washing, etc., which costs around $11,000 per liter to ship up. So NASA is looking to trim this price in favor of a "vile cocktail" of recycled astronauts' urine, sweat, and even lab rats' liquid waste. 

     Storing fresh water takes up too much room, which makes recycling essential. A key part of the "water recovery" program is to recoup about 85 percent of the H2O in urine, leaving behind a "brine" that is then checked for other particles and compounds. A catalytic reaction is used, with oxygen injected to kill off bacteria, fungi, or viruses. Iodine is added to prevent microbial colonization. 

     NASA engineer Layne Castor says that once the murky water is ready, there's no hint of sewage, just a slight medicinal tang from the iodine. The remaining organic compounds are less than 2 percent of what's in typical U.S. tap water. Finally, a filter mops up the iodine to avert iodine overdosing during long stays on the Station.

"When astronauts set foot on the moon once again," says Muir, "their pee may– quite literally– be worth its weight in gold."

Q. When 30 males with strong party identification watched a political debate, their fMRI brain scans showed high activation in the orbital frontal cortex (emotions), anterior cingulate (conflict resolution), posterior cingulate (conflicts of moral accountability) and afterward, the ventral striatum (reward/pleasure).  Can you guess what part of their brains didn't register at all? –J. Jane

A. The dorsolateral prefrontal cortex, most associated with reasoning, says Michael Shermer in Scientific American. "It appears as if partisans work to get the conclusion they want, then massively reinforce themselves for doing so," sums up lead researcher Drew Westen. The implications for law, politics, and business are of great concern. Even scientific research can be undercut by ardent theory-holders, in spite of double-blind studies, replication and peer review.

     The villain here is "confirmation bias," where we all judiciously seek confirming evidence in support of our already existing beliefs while ignoring or reinterpreting disconfirming facts and findings, thus allowing unconscious emotionality to masquerade as inner debate.

     Shermer's advice: "Skepticism is the antidote."

Q. Digging into the "bioluminescence" file, what are a few of the world's truly strange night light sights? –S.T. Coleridge

A. Breathtaking is the Asiatic firefly, whose flashing has been described by H. M. Smith and reported in Jearl Walker's Flying Circus of Physics. Imagine a tree 40 feet tall with a firefly on every leaf all flashing in unison every second or so, and total darkness between the flashes. Imagine a tenth of a mile of these flashing trees along a riverfront, and all flashing in perfect unison. "Then, if your imagination is sufficiently vivid, you may form some conception of this amazing spectacle."

     Many other organisms also produce light. The Brazilian railroad worm has a red light on its head and green lights down its side. The single-celled dinoflagellates are said to "set the sea on fire" when disturbed.

     One crustacean, Cypridina hilgendorfii, can be made to glow by moistening it after it has been dried– done by Japanese soldiers during World War II when using a stronger light was too dangerous. Spitting on a dried crustacean would give off just enough light to read a map.

     Natural bacterial action has reportedly made potatoes glow brightly enough for reading in an otherwise dark room. "There has even been a case in which a corpse glowed in the dark," says Walker. "But the most disturbing, especially if one is relying on darkness to conceal a slight indiscretion, have been the times in which urine glowed in the dark."

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