When Do Fish Sleep? Part 1

WHEN DO.

FISH SLEEP?.

David Feldman.

Preface.

Imponderables are mysteries that can't be answered by numbers, measurements, or a trip to the reference section of your library. If you worry about why the carbons on airplane tickets are red, or why tennis b.a.l.l.s are fuzzy, or why yawning is contagious, you have been struck by the dread malady of Imponderability.

When we wrote the first volume of Imponderables, we weren't sure that there were others like us, who were committed to cogitating about the everyday mysteries of life. We needn't have worried. Most of the Imponderables in this book were submitted by readers of the first two volumes of Imponderables.

In Why Do Clocks Run Clockwise?, we introduced a new section, Frustables (short for "frustrating Imponderables") and asked for your help in solving them. Your response was terrific, but we don't want you to get complacent. We've got ten new Imponderables that we haven't been able to solve.

And because so many readers offered corrections and caustically constructive comments, we've added a letter section-we couldn't shut you up anymore even if we wanted to.

Would you like to win a free copy of the next volume of Imponderables? If you are the first to submit an Imponderable that we use in the next book, you will not only have the relief of finally having the answer to your mystery, but also a free, autographed copy of the book (along with, of course, an acknowledgment).

The last page of the book tells you how to get in touch with us. But for now, sit back and enjoy. You are about to enter the wonderful world of Imponderability.

Why Do Roosters Crow in the Morning?

Because there are humans around to be awakened, of course. Does anyone really believe that roosters crow when they are by themselves? Nah! Actually, they speak perfectly good English.

Ornithologists don't buy our common-sense answer. They insist that crowing "maps territory" (a euphemism for "Get the h.e.l.l out of my way and don't mess with my women-this is my coop"). In the spirit of fair play, we'll give the last world to one of those nasty ornithologist types (but don't believe a word she says), Janet Hinshaw, of the Wilson Ornithological Society: Most of the crowing takes place in the morning, as does most singing, because that is when the birds are most active, and most of the territorial advertising takes place then. Many of the other vocalizations heard throughout the day are for other types of communication, including flocking calls, which serve to keep members of a flock together and in touch if they are out of sight from one another.

Submitted by Rowena Nocom of North Hollywood, California.

Why Do Many Hotels and Motels Fold Over the Last Piece of Toilet Paper in the Bathroom?

This Imponderable was sent in by reader Jane W. Brown in a letter dated May 12, 1986. Jane was clearly a discerning seer of emergent popular culture trends: Staying in less than deluxe lodgings has led me to wonder why, and how, the custom of folding under the two outside corners on a roll of bathroom paper was begun. This operation creates a V on the last exposed edge of the tissue. I first noticed this bizarre sight in a LaQuinta Motor Inn. Then I stayed in some Holiday Inns while on a business trip. There, too, the bathroom paper had been tediously tucked in on the outside edges, the large V standing out, begging for attention. Recently, I upgraded my accommodations and spent several nights in a Marriott and an Intercontinental. Right: the bathroom paper was also arranged in this contorted fashion. Why?

Jane, enterprisingly, included an audiovisual aid along with her letter, as if to prove she wasn't crazy: a specimen of the mysterious V toilet paper. Since Jane wrote her letter, the folded toilet paper trick has run rampant in the lodging industry.

We contacted most of the largest chains of innkeepers in the country and received the same answer from all. Perhaps James P. McCauley, executive director of the International a.s.sociation of Holiday Inns, stated it best: Hotels want to give their guests the confidence that the bathroom has been cleaned since the last guest has used the room. To accomplish this, the maid will fold over the last piece of toilet paper to a.s.sure that no one has used the toilet paper since the room was cleaned. It is subtle but effective.

Maybe too subtle for us. Call us sentimental old fools, but we still like the old "Sanitized for Your Protection" strips across the toilet seat.

Submitted by Jane W. Brown of Giddings, Texas.

Why Do Gas Gauges in Automobiles Take and Eternity to Go from Registering Full to Half-full, and Then Drop to Empty in the Speed of Light?

On a long trek down our ill.u.s.trious interstate highway system, we will do anything to alleviate boredom. The roadway equivalent of reading cereal boxes at breakfast is obsessing about odometers and fuel gauges.

Nothing is more dispiriting after a fill-up at the service station than traveling sixty miles and watching the gas gauge stand still. Although part of us longs to believe that our car is registering phenomenal mileage records, the other part of us wants the gauge to move to prove to ourselves that we are actually making decent time and have not, through some kind of Twilight Zone alternate reality, actually been riding on a treadmill for the last hour. Our gas gauge becomes the arbiter of our progress. Even when the needle starts to move, and the gauge registers three-quarters' full, we sometimes feel as if we have been traveling for days.

How nice it would be to have a gauge move steadily down toward empty. Just as we are about to give in to despair, though, after the gauge hits half-full, the needle starts darting toward empty as if it had just discovered the principle of gravity. Whereas it seemed that we had to pa.s.s time zones before the needle would move to the left at all, suddenly we are afraid that we are going to run out of gas. Where is that next rest station?

There must be a better way. Why don't fuel gauges actually register what proportion of the tank is filled with gasoline? The automakers and gauge manufacturers are well aware that a "half-full" reading on a gas gauge is really closer to "one-third" full, and they have reasons for preserving this inaccuracy.

The gauge relies upon a sensor in the tank to relay the fuel level. The sensor consists of a float and linkage connected to a variable resistor. The resistance value fluctuates as the float moves up and down.

If a gas tank is filled to capacity, the liquid is filled higher than the float has the physical ability to rise. When the float is at the top of its stroke, the gauge will always register as full, even though the tank can hold more gasoline. The gauge will register full until this "extra" gasoline is consumed and the float starts its descent in the tank. At the other end of the float's stroke, the gauge will register as empty when the float can no longer move further downward, even though liquid is present below the float.

We asked Anthony H. Siegel, of Ametek's U.S. Gauge Division, why sensors aren't developed that can measure the actual status of gasoline more accurately. We learned, much as we expected, that more precise measurements easily could be produced, but the automakers are using the current technology for our own good: Vehicle makers are very concerned that their customers do not run out of fuel before the gauge reads empty. That could lead to stranded, unhappy motorists, so they compensate in the design of the float/gauge system. Their choice of tolerances and calibration procedures guarantees that slight variations during the manufacturing of these components will always produce a combination of parts which falls on the safe side. The gauge is thus designed to read empty when there is still fuel left.

Tens of millions of motorists have suspected there is fuel left even when the gauge says empty, but few have been brave enough to test the hypothesis. Perhaps there are gallons and gallons of fuel left when the gauge registers empty, and this is all a plot by Stuckey's and Howard Johnson's to make us take unnecessary pit stops on interstates.

Submitted by Jack Belck of Lansing, Michigan.

How Is the Caloric Value of Food Measured?

Imponderables is on record as doubting the validity of caloric measurements. It defies belief that the caloric value of vegetables such as potato chips and onion rings, full of nutrients, could possibly be higher than greasy tuna fish or eggplant. Still, with an open mind, we sought to track down the answer to this Imponderable.

Calories are measured by an apparatus called a calorimeter. The piece of food to be measured is placed inside a chamber, sealed, and then ignited and burned. The energy released from the food heats water surrounding the chamber. By weighing the amount of water heated, noting the increase in the water's temperature and multiplying the two, the energy capacity of the food can be measured. A calorie is nothing more than the measurement of the ability of a particular nutrient to raise the temperature of one gram of water one degree Centigrade. For example, if ten thousand grams of water (the equivalent of ten liters or ten thousand cubic centimeters) surrounding the chamber is 20 degrees Centigrade before combustion and then is measured at 25 degrees after combustion, the difference in temperature (five degrees) is multiplied by the volume of water (ten thousand grams) to arrive at the caloric value (fifty thousand calories of energy).

If fifty thousand calories sounds like too high a number to describe heating ten liters of water five degrees, your instincts are sound. One calorie is too small a unit of measurement to be of practical use, so the popular press uses "Calories," really kilocalories, one thousand times as much energy as the lowercase "calorie."

The calorimeter is a crude but reasonable model for how our body stores and burns energy sources. The calorimeter slightly overstates the number of calories our body can use from each foodstuff. In the calorimeter, foods burn completely, with only some ashes (containing minerals) left in the chamber. In our body, small portions of food are indigestible, and are excreted before they break down to provide energy. The rules of thumb are that two percent of fat, five percent of carbohydrates, and eight percent of proteins will not be converted to energy by the body.

Food scientists have long known the caloric count for each food group. One gram of fat contains more than twice the number of calories (nine).

Scientists can easily ascertain the proportion of fat to carbohydrates or proteins, so it might seem that calories could be measured simply by weighing the food. When a food consists exclusively of proteins and carbohydrates, for example, one could simply multiply the weight of the food by four to discover the calorie count.

But complications arise. Certain ingredients in natural or processed foods contain no caloric value whatsoever, such as water, fiber, and minerals. Foods that contain a mixture, say, of water (zero calories), fiber (zero calories), proteins (four calories per gram), fats (nine calories per gram), and carbohydrates (four calories per gram), along with some trace minerals (zero calories), are simply harder to calculate with a scale than a calorimeter.

Submitted by Jill Palmer of Leverett, Ma.s.sachusetts.

Who Put E on Top of the Eye Chart? And Why?

Professor Hermann Snellen, a Dutch professor of ophthalmology, put the E on top of the eye chart in 1862. Although his very first chart was headed by an A, Snellen quickly composed another chart with E on top.

Snellen succeeded Dr. Frans Cornelis Donders as the director of the Netherlands Hospital for Eye Patients. Donders was then the world's foremost authority on geometric optics. Snellen was trying to standardize a test to diagnose visual acuity, to measure how small an image an eye can accept while still detecting the detail of that image. Dr. Donders' complicated formulas were based on three parallel lines; of all the letters of the alphabet, the capital E most closely resembled the lines that Dr. Donders had studied so intensively. Because Donders had earlier determined how the eye perceives the E, Snellen based much of his mathematical work on the fifth letter.

The three horizontal limbs of the E are separated by an equal amount of white s.p.a.ce. In Snellen's original chart, there was a one-to-one ratio between the height and width of the letters, and the gaps and bars were all the same length (in some modern eye charts, the middle bar is shorter).

Louanne Gould, of Cambridge Instruments, says that the E, unlike more open letters like L or U, forces the observer to distinguish between white and black, an important consit.i.tuent of good vision. Without this ability, E's begin to like B's, F's, P's or many other letters.

Of course, Snellen couldn't make an eye chart full of only E's, or else all his patients would have 20-10 vision. But Snellen realized that it was important to use the same letters many times on the eye charts, to insure that the failure of an observer to identify a letter was based on a visual problem rather than the relative difficulty of a set of letters. Ian Bailey, professor of optometry and director of the Low Vision Clinic at the University of California at Berkeley, says that it isn't so important whether an eye chart uses the easiest or most difficult letters. Most eye charts incorporate only ten different letters, ones that have the smallest range of difficulty.

Today, many eye charts do not start with an E-and there is no technical reason why they have to-but most still do. Dr. Stephen C. Miller, of the American Optometric a.s.sociation, suggests that the desire of optical companies to have a standardized approach to the production of eye charts probably accounts for the preponderance of E charts. And we're happy about it. It's a nice feeling to know that even if our vision is failing us miserably, we'll always get the top row right.

Submitted by Merry Phillips of Menlo Park, California.

Do the Police Really Make Chalk Outlines of Murder Victims at the Scene of the Crime? Why Do They Use Chalk?

As soon as law enforcement officials descend upon a murder scene, a police photographer takes pictures of the corpse, making certain that the deceased's position is established by the photographs. The medical examiner usually wants the body as soon as possible after the murder; the sooner an autopsy is conducted, the more valuable the information the police are likely to obtain.

Right before the body is removed, the police do indeed make an outline of the position of the victim. More often than not the body is outlined in chalk, including a notation of whether the body was found in a p.r.o.ne or supine posture.

A police investigation of a murder can take a long time, too long to maintain the murder site as it appeared after the murder. Forensic specialists cannot rely on photographs alone. Often, the exact position of the victim can be of vital importance in an investigation. By making an outline, the police can return to the murder scene and take measurements which might quash or corroborate a new theory on the case. Outline drawings may also be used in the courtroom to explain wound locations, bullet trajectories, and blood trails.

Herbert H. Buzbee, of the International a.s.sociation of Coroners and Medical Examiners, told Imponderables that chalk is not always used to make outlines. Stick-em paper or string are often used on carpets, for example, where chalk might be obscured by the fabric. Carl Harbaugh, of the International Chiefs of Police, says that many departments once experimented with spray paint to make outlines, but found that paint traces were occasionally found on the victim, confusing the forensic a.n.a.lysis.

The ideal outline ingredient would be one that would show up, stay put, and do no permanent damage to any surface. Unfortunately, no such ingredient exists. Chalk gets high marks for leaving no permanent markings, but is not easily visible on many surfaces. Tape and string (which has to be fastened with tape) have a tendency to mysteriously twist out of shape, especially if they get wet.

None of these flaws in the markers would matter if murder victims were considerate enough to die in sites convenient to the police. Harbaugh says that on a street or highway any kind of outline will do. But what good is a chalk outline on a bed covered with linens and blankets?

Submitted by Pat O'Conner of Forest Hills, New York.

What Do Restaurants that Specialize in Potato Skins Do with the Rest of the Potato? What Do Restaurants that Specialize in Frogs' Legs Do with the Rest of the Frog?

In most restaurants, potato skins are a waste product, served as the casing of a baked potato or not at all. So we a.s.sumed that restaurants that specialized in potato skins used the rest of the potato to make mashed potatoes, boiled potatoes, or soups.

Our a.s.sumption was correct, but our correspondent mentions that potato skins are often served in bars that do not serve potatoes in any other form. Is it cost-effective for these establishments to serve the skins and dump the potato filling?

Most restaurants that serve potato skins buy the skins only, usually in frozen form. Linda Smith, of the National Restaurant a.s.sociation, sent us a list of the biggest suppliers of potato skins. Most of these companies, not at all coincidentally, also supply restaurants with pre-cut cottage fries, hash browns, and O'Brien potatoes, among others. Ore-Ida isn't about to sell the skin and throw away the potato.

Anyone who has ever dissected a frog in biology cla.s.s does not want to contemplate the idea of chefs picking apart an entire frog to get at its legs. Suffice it to say that restaurants buy only the legs of frogs. What suppliers of frogs' legs do with the rest of the frog is too gruesome for even us to contemplate.

Submitted by Myrna S. Gordon of Scotch Plains, New Jersey. Thanks also to Sharon Michele Burke of Menlo Park, California.

If Water Is Heavier than Air, Why Do Clouds Stay Up in the Sky?

What makes you think that clouds aren't dropping? They are. Constantly.

Luckily, cloud drops do not fall at the same velocity as a water balloon. In fact, cloud drops are downright sluggards: They drop at a measly 0.3 centimeters per second. And cloud drops are so tiny, about 0.01 centimeters in diameter, that their descent is not even noticeable to the human eye.

Submitted by Ronald C. Semone of Washington, D.C.

Why Are There More Holes in the Mouthpiece of a Telephone than in the Earpiece?

We just checked the telephone closest to us and were shocked. There are thirty-six holes on our mouthpiece, and a measly seven on the earpiece. What gives?

Tucked underneath the mouthpiece is a tiny transmitter that duplicates our voices, and underneath the earpiece is a receiver. Those old enough to remember telephones that constantly howled will appreciate the problems inherent in having a receiver and transmitter close together enough to produce audible transmission without creating feedback.

Before the handset, deskstand telephones were not portable, and the speaker had to talk into a stationary transmitter. Handsets added convenience to the user but potential pitfalls in transmission. While developing the telephone handset, engineers were aware that it was imperative for the lips of a speaker to be as close as possible to the transmitter. If a caller increases the distance between his lips and the transmitter from half an inch to one inch, the output volume will be reduced by three decibels. According to AT&T, in 1919 more than four thousand measurements of head dimensions were made to determine the proper dimensions of the handset. The goal, of course, was to design a headset that would best cup the ear and bring the transmitter close to the lips.

One of the realities that the Bell engineers faced was that there was no way to force customers to talk directly into the mouthpiece. Watch most people talking on the phone and you will see their ears virtually covered by the receiver. But most people do not hold their mouths as close to the transmitter. This is the real reason why there are usually more holes in the mouthpiece than in the earpiece. The more holes there are, the more sensitive to sound the transmitter is, and the more likely that a mumbled aside will be heard three thousand miles away.

Submitted by Tammy Madill of Millington, Tennessee.