How Does Aspirin Find a Headache?

by David Feldman

  Submitted by Dr. Ray Watson of Shively, Kentucky.

  Why Is It That What Looks to Us Like a Half-Moon Is Called a Quarter-Moon by Astronomers?

  An intriguing Imponderable, we thought, at least until Robert Burnham, editor of Astronomy, batted it away with the comment, “Aw, c’mon, you picked an easy one this time!”

  Much to our surprise, when astronomers throw lunar fractions around, they are referring to the orbiting cycle of the Moon, not its appearance to us. Sky & Telescope’s associate editor, Alan M. MacRobert, explains:

  The Moon is half lit when it is a quarter of the way around its orbit. The count begins when the moon is in the vicinity of the sun (at “new Moon” phase). “First quarter” is when the Moon has traveled one-quarter of the way around the sky from there. The Moon is full when it is halfway around the sky, and at “third quarter” or “last quarter” when it’s three-quarters of the way around its orbit.

  Robert Burnham adds that “quarter-Moons” and “half-Moons” aren’t the only commonly misnamed lunar apparitions. Laymen often call the crescent moon hanging low in the evening sky a “New Moon,” but Burnham points out that at this point, the moon is far from new: “In fact, by then the crescent Moon is some three or four days past the actual moment of New Moon, which is the instant when the center of the Moon passes between the Earth and Sun.”

  Submitted by Susan Peters of Escondido, California. Thanks to Gil Gross, of New York, New York.

  What’s the Deal with the Grades of Architectural and Art Pencils? What Do “H,” “HB,” “F,” “B,” and “E” Stand For?

  Here’s the code: “H” stands for Hardness and “B” stands for “Black.” With pencils, “hard” means a pencil that yields a lighter image. “Soft” pencils provide darker images. In this case, “black” means soft.

  From hardest to softest, these are the grades: 9H, 8H, 7H, 6H, 5H, 4H, 3H, 2H, H, HB, F, B, 2B, 3B, 4B, 5B, 6B.

  HB is the equivalent of the “regular” number 2 pencil. The grade “F” is a grade between “HB” (hard and black) and “B.” Ellen Carson, of pencil manufacturer Empire Berol USA, told us that “F” was originally introduced for taking shorthand, because it was “hard enough to withstand extended use without resharpening and black enough so as to ensure that the shorthand was subsequently legible.”

  The “E” grades are used to designate the hardness of Filmograph leads. According to Carson, these leads are produced for plastic film and used in technical drawing. Filmograph leads contain no graphite and are based upon polymers and carbon black: “They are used in order to prevent the written or drawn line from being smudged when the drawing is being handled.” E1 is the softest grade and E4 the hardest.

  Submitted by Myron Kozman of Webster Groves, Missouri. Thanks also to Carol McDaniel of Castro Valley, California, and Roslyn J. Dy of Charleston, West Virginia.

  How Do Hermit Crabs “Relieve Themselves” When in the Shell Without Getting Filthy? Or Do They Get Filthy?

  The last few chapters have been altogether too pleasant. We don’t want you to get complacent; it’s time for a real gross-out now.

  We often hear the bromide about the perfection of Mother Nature—that everything is part of her plan. But she had some strange plans in mind when she created the hermit crab. A “hermit crab” is not a particular species or family of crab; the term refers to various crabs that have soft abdomens and live in the empty shells of mollusks. The vision of a crab living in a vacated snail shell isn’t too appetizing to begin with; but combine it with the crustacean’s questionable bathroom habits, and we are stuck with one unpleasant visual image.

  We asked one of our favorite crustacean experts, Dr. Darryl Felder, chairman of the biology department at the University of Louisiana, Lafayette, to explain our Imponderable. Even this expert couldn’t remain clinical:

  Their urine is passed from pores at the base of the antennae, near the base of the eyes (as in all crabs, shrimp, and lobsters). The fecal material is passed from the posterior end deep within the shell and moved as a string-like fecal strand out the aperture of the shell. You too would be a “hermit” if you did such things in your home.

  Not content to render an expert opinion on such a weighty subject alone, Dr. Felder was kind enough to pass along our query to Dr. Rafael Lemaitre, a research zoologist at the National Museum of Natural History at the Smithsonian Institution. Dr. Lemaitre concurred with all of Dr. Felder’s conclusions but was kind enough to provide even more repellent details:

  …many worms, amphipods [crustaceans with one set of feet for jumping or walking and a separate set for swimming], and other animals are frequently found inside shells inhabited by hermits. It is quite possible that some of these “associates” help in the recycling of the hermit’s wastes.

  Lemaitre adds that the hermit crab can, by itself, create the currents necessary to flush the wastes out of its system. And if its plumbing fails, and it gets too grubby for the crustacean, it can always do what is most characteristic of a hermit crab: Ditch the shell it’s living in and find more pristine accommodations elsewhere.

  Submitted by Elaine Coyne of Brick, New Jersey.

  Why Does Getting a Hair in Our Mouth Make Us Gag?

  Our correspondent, Ilona Savastano, was passionate in her need for an answer to this burning Imponderable:

  How are we able to swallow just about any type of food, at times very large mouthfuls of it, with no problem, and yet we nearly gag to death if we get a tiny little hair in our mouth? I feel even one piece of fur in our mouth? doesn’t quite bring the same “yucky” reaction.

  We flew your question by our dental experts, who are used to patients gagging (sometimes even before they receive their bill).

  Their first reaction was to emphasize the sensitivity of the mouth. Dentist Ike House, of Haughton, Louisiana, amplifies:

  Our mouths are the most sensitive parts of our bodies, especially at birth and in childhood. Children use their mouths for food (nursing), comfort (thumb-sucking or pacifier), pleasure (witness the random exploration of children with their hands in their mouths), and exploration (children put a foreign object in their mouths to determine what it is). Because of our pattern of oral stimulation and exploration from an early age, the mouth is very sensitive.

  Now that we have established how sensitive our mouths are, we might ask whether there is anything particularly nasty about the hair itself that might cause particular problems if found in the mouth. Yes, indeed, insist our experts. Dentist Barnet Orenstein, of the New York University David B. Kriser Dental Center, explains:

  Physically, a hair has two sharp ends capable of stimulating the very sensitive mucous membrane lining the oral cavity. Furthermore, the fine diameter and convoluted shape of a hair enable it to adhere to the mucosa. Dislodgement with the tip of the tongue is virtually impossible.

  The gag reflex isn’t necessarily more likely to occur when the mouth is full than when it contains one lonely hair. We can be tickled more easily by the light touch of a feather on the neck than by a hard rubbing of a bulkier object.

  But the main culprit in hair-gagging is well above the throat. All of our dental experts think that the main cause of hair-gagging is psychological.

  Dr. House reports that he has often been able to decrease or eliminate a patient’s gag reflex simply by talking to him or her about the problem. And he opines that the nature of a foreign body determines our reaction to it:

  For example, spaghetti would not feel much different in our mouth than worms (assuming you had some GREAT sauce, and the worms were already dead and not wiggling around) but most people would choke at the thought. Hair is perceived as being dirty by most folks, witness the displeasure people have with finding a hair in their food. During lovemaking, however, touching your partner’s hair with your mouth might be enjoyable.

  So buck up, Ilona. Sure, you may not be able to control your gag on a single stand of hair, but blame the messenger, not the message. Gagging can be good
for you, as Dr. Orenstein explains:

  The gag reflex is one of the many defense mechanisms nature has so miraculously endowed us with. Even infants will react violently to tickling of the soft palate. If it were not for this mechanism, many of us would expire by having the airway shut off by some foreign body lodged in our throat.

  Submitted by Ilona M. Savastano of Cleveland, Ohio. Thanks also to Herbert Biern of Reston, Virginia.

  Why Does Pasta Create Foam When Boiling?

  Pasta is made from durum wheat, a particularly hard wheat. More precisely, pasta is created from durum wheat semolina, fine particles derived from the much coarser durum. The extraction of the semolina is largely responsible for the foaming of pasta when cooking, as Farook Taufiq, vice-president of quality assurance at Prince Company, explains:

  Durum wheat semolina consists of carbohydrates (starches) and protein. In the process of grinding wheat to extract semolina, some starch links are broken.

  When pasta is put in boiling water, these broken starch links swell up, taking in tiny air bubbles, along with water. These air bubbles come to the surface of the boiling water and appear as foam. So the foam is a combination of starch molecules, water, and air.

  Submitted by Sam Rosenthall of Amherst, Massachusetts.

  Why Do Many Elderly People, Especially Those Missing Teeth, Constantly Display a Chewing Motion?

  Dr. John Rutkauskas, of the American Society for Geriatric Dentistry, consulted with two of his geriatric dentistry colleagues, Dr. Saul Kamen and Dr. Barry Ceridan, and told Imponderables that this chewing motion is found almost exclusively in people who have lost teeth. On rare occasions, certain tranquilizers or antidepressants (in the phenothiazine family) may cause a side effect called tardive dyskinesia, an inability to control what are ordinarily voluntary movements. These movements are as likely to involve the nose as the mouth or jaws, though.

  In most cases, Rutkauskas believes that the chewing motion is a neuromuscular response to the lack of teeth: an attempt by the oral cavity to achieve some form of equilibrium. In particular, these sufferers can’t position their upper and lower jaws properly. With a full set of ivories, the teeth act as a stop to keep the jaws in place.

  Of course, most people who lose teeth attempt to remedy the problem by wearing dentures. And most people adapt well. But Ike House, a Louisiana dentist and Imponderables reader (we’re sure he is prouder of the first qualification), told us that a significant number of elderly people have lost the ability to wear dentures at all because of an excessive loss of bone:

  They can close their mouth much fuller than they would with teeth present, resulting in the “nose touching skin” appearance of many elderly folks. Since the normal “rest position” of about 2-3 mm between the upper and lower natural or artificial teeth is not able to be referenced, they may be constantly searching for this position.

  Many elderly people who wear dentures feel that the prostheses just don’t feel normal. And restlessness leads to “chewing in the air,” as House amplifies:

  If you had two objects in your hands, such as two pecans or two coins, you would probably manipulate them in some way. When not using a pen or pencil, for example, but holding it passively, we usually move it in our hand. It may be that folks wearing dentures constantly manipulate them in some way just because objects being held but not used are often moved by unconscious habit.

  I have a great-uncle who lets his upper teeth fall down between words and pushes them back up against his palate. This is a most disconcerting habit to his family! I know some elderly patients cannot tolerate dentures in their mouths unless they are eating because they can’t leave them alone.

  Barnet B. Orenstein, an associate clinical professor of dentistry at New York University’s College of Dentistry, told Imponderables that the tongue is often the culprit in creating the chewing motion:

  Elderly people often display a constant chewing motion because, having lost their lower teeth, their tongue is no longer confined to the space within the dental arch. The tongue spreads out and actually increases in size. What appears to be a chewing motion is actually a subconscious effort to find a place for the tongue.

  The last time we were at the Imponderables staff’s official dentist, Phil Klein, of Brooklyn Heights, we asked him to wrestle with this mystery while he mauled our molars (and we pondered whether we could deduct the office visit from our income tax as a research as well as medical expense). Much to our relief, Dr. Klein concurred with the theories stated above but raised the possibility of a few others, including rare neurological conditions and grinding of teeth to the point where the lower and upper jaws can’t mesh comfortably.

  Klein also mentioned that problems with salivation, and particularly dryness, is a constant problem for numerous elderly people, and many with this problem move their mouth and jaw in response to this dryness.

  And then he told us we had no cavities.

  Submitted by Dennis Kingsley of Goodrich, Michigan.

  Note to IRS: We deducted our trip to Dr. Klein as a medical expense.

  Do Butterflies (and Other Insects) Sneeze or Cough? If So, Do They Do So Loud Enough for Humans to Hear?

  All of the entomologists we contacted were sure about this Imponderable. Butterflies and other insects don’t sneeze or cough. It’s particularly difficult for them to sneeze, as they don’t possess true noses.

  So then how do insects breathe? Leslie Saul, Insect Zoo director at the San Francisco Zoo, explains:

  Butterflies and other insects breathe through holes in the sides of their bodies called spiracles. Spiracles are provided with valvelike devices that keep out dust and water. Some insects, such as some flies, june beetles, lubber grasshoppers, and notably the Madagascar hissing cockroaches, make sounds for communication purposes by forcing air out through the spiracles. Hence they hiss.

  Karen Yoder, certification manager of the Entomological Society of America, concurs with Saul and adds that it isn’t possible to hear insects breathing with the naked ear, either:

  In my days of insect appreciation, I have never heard the expiration of air from an insect…. Certainly, it could be possible to hear the transpiration in insects with the aid of an amplifier, but not with the naked ear.

  But one needn’t be wearing a stethoscope to hear the aforementioned hissing cockroach, better known to entomologists as Gromphadorhina portentosa. Our trusted informant, Randy Morgan, head keeper at Cincinnati’s Insectarium, wrote an article for Backyard Bugwatching, a favorite magazine of our family’s to pass around at barbecues, in which he chronicles the decibel-producing potential of these two-to three-inch cockroaches.

  The Madagascar hissing cockroaches produce the hiss by contracting their abdomens and pushing the air out of constricted spiracles: The noise can be heard from several feet away. Whereas most cockroaches deter predators by running away, flying away, or producing unpleasant secretions, not so the Gromphadorhina portentosa: “Their secretive nature and ability to hiss seem to be their primary defense against enemies.” Morgan cites an example of a lemur, eager to dine on our poor cockroach. But the hiss convinces the lemur it might have a rattlesnake or other dangerous critter on its hands: “In the leaves, a hissing cockroach continued feeding, unaware it had just narrowly escaped being eaten.” Even if the cockroach wasn’t aware of its near demise, the lemur’s flight wasn’t a coincidence. The hiss is a voluntary reflex, generally used only when a cockroach is in danger from predators or competing for mates.

  Submitted by Marti Miller of Flagstaff, Arizona. Thanks also to Russell Shaw of Marietta, Georgia.

  What Is the Liquid That Forms on Top of Yogurt? Is It Water or Does It Have Nutrients? Should It Be Drained or Stirred Back into the Yogurt?

  That liquidy stuff is whey, the very stuff that Little Miss Muffet ate on a tuffet. When the bacteria that forms yogurt grows sufficiently, the milk coagulates. The proteins squeeze together and form curds, pushing out the watery whey.

  Whey may be watery,
but it isn’t water. Whey contains sugar, minerals, some protein, and lactose. Don’t waste it. Mix it back in with the rest of the yogurt. You’ll be a better person (nutritionally, anyway) for it.

  Submitted by Emanuel Kelmenson of Jericho, New York.

  Why Do Most Yogurts Come with the Fruit on the Bottom? Why Not on the Top? Or Prestirred?

  We had no idea that this topic so consumed yogurt lovers. But our dairy consultants indicated that yogurt lovers have strong feelings about where to put the fruit in their yogurt containers. Dairy expert Bruce Snow told us that there is no difference in the contents of fruit-on-the-bottom yogurts versus prestirred varieties, but added: