Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, January 14, 1993 TAG: 9301130112
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: Joel Achenbach
DATELINE: LENGTH: Long
NOT JUST ANY ATOMS WILL BLOW YOU UP
Q: Why can't you make an atomic bomb out of lead, or silver, or gold, or Mars Bars for that matter? Why can you make a bomb out of uranium or plutonium but not out of neptunium, the element between them on the periodic table?A: This is what we all know about atomic physics: If you split the atom you have achieved "fission" and everyone dies; a single grain of plutonium can kill an elephant at 500 yards; and there was once a man named Enrico Fermi.
Fortunately we are now ready to educate everyone even further. We posed our daffy, brain-dead questions to Henry Kendall, a professor of physics at MIT who, at the end of our conversation, politely noted that he had recently shared a Nobel Prize for discovering quarks. So he's what you'd call an expert.
The main thing you need to know is that lots of atoms can be split, but few are as inviting as uranium and plutonium. These two elements are special because they're really big. They have obese nuclei, just waiting for someone to take a pot shot at them (with a neutron). Big atoms have lots of energy that can be released if the atom is split.
"The reason this doesn't work with silver or lead or zinc or copper or anything else is [among other things] there's not enough electricity in there to really take over if you try to split the nucleus," Kendall said.
Neptunium is big, too, but it's virtually non-existent in nature, because after a couple of days it tends to decay into a simpler kind of atom. Plutonium also isn't found in nature, but you can make it inside a nuclear reactor, using uranium, which can be yanked out of the ground by the ton.
There's another factor: Only certain types of uranium and plutonium are good for making bombs. You want one of the more rickety isotopes, a type of uranium or plutonium that has an atomic structure that's unstable and is easily split apart. "You need a certain incipient instability in the nucleus," Kendall said.
Finally, to achieve either nuclear power or an explosion you need to have a chain reaction, which is tricky, in part because of the danger that you might suddenly be vaporized. A nuclear chain reaction is when a neutron strikes an atom and splits it in a way that creates more loose neutrons, which in turn split more atoms. They do this slowly in nuclear power plants; in a bomb, you design it to happen in a fraction of a second.
We find all this to be fairly reassuring: Those nuclear forces, so fundamental that they are found in every fragment of matter and so powerful that they can level an entire city, are not poised on a hair trigger, waiting to annihilate us. It's certainly true that there's enough energy bound up inside a Mars Bar to turn your neighborhood into a smoking ashheap. But go ahead and bite into it anyway.
Q: Why don't male monkeys and gorillas go bald? If this whole evolution business is true, then how come you never see a chrome-domed ape? How come there's not a single orangutan at the zoo who you could, in good conscience, refer to as "Cueball"?
A: The truth is that two species of primates - the chimpanzee and the stump-tailed macaque - have pattern baldness. Not all chimps become bald, but all macaques do, both males and females. We know this because there are, wouldn't you know it, people who study baldness among apes, once again proving our assertion that every good job has already been taken.
Arthur Diani, a senior scientist at the Upjohn Co., says he has successfully used Rogaine to reverse baldness within his colony of 87 macaques (an act of human kindness and charity that we vow never to forget). He says he can explain the chemical causes of baldness (testosterone turns into dihydrotestosterone and converts the hair follicle into the "vellus" stage, yakkety yak), but not the evolutionary reasons for it.
Thus we are left with this mental nugget: Since humans share the trait of baldness with chimps but not with other apes, this may support the argument that humans and chimps are genetically more closely related than chimps are with other primates. We're in this thing together.
The Mailbag:
A mysterious K.P. of Cocoa, Fla., asks, "Why is it that when you accidentally put something in the wash that fades red-pink dye on other garments, this same red-pink dye which came out of the original garment so easily will not, in a million washings, come out of the faded-upon garment?"
Dear K.P.: We immediately contacted The Soap and Detergent Association (they stipulate the "The," so we're tempted to call it the The Soap and Detergent Association), which put us in touch with the American Association of Textile Chemists and Colorists, and they point out that dye is designed not to wash out of fabric. That explains why your underwear is still pink. The reason that the dye left your original garment is that it had too much dye to begin with, and that excess dye was just sitting there on the surface, waiting to run amok in your washer. When you discover that your drawers have turned pink, don't put them in the dryer and bake the dye; instead, soak them and wash them again.
Laundry tips. What have we come to. Washington Post Writers Group
Joel Achenbach writes for the Style section of The Washington Post.