Why Don’t Tornadoes Ever Seem to Hit Big Buildings or Big Cities?
The operative word in this mystery is seem. For all of our meteorological experts agree with Harold Brooks, the head of the Mesoscale Applications Group of the National Severe Storms Laboratory in Norman, Oklahoma, who states:
There is a myth that tornadoes don’t hit downtowns, but that is just a myth that comes from the fact that downtowns are small areas. If you randomly picked any other similarly sized areas in the middle of the United States, they wouldn’t get hit often, either.
In other words, tornadoes are non-discriminatory offenders, and are subject to the laws of probability. The land covered by major population centers is tiny compared to the total expanse of North America, but a big city is theoretically just as likely to get hit as all the local trailer parks if they covered as much of an expanse as the downtown area.
There are portions of the United States where tornadoes are much more likely to hit, however. Tornadoes have been tracked in all fifty U.S. states, but the so-called tornado alleys are the Midwestern area from Texas all the way north to the Canadian border, in the southeastern United States, and in the Ohio Valley and southern Great Lakes region, extending as far east as western Pennsylvania. But within that general area, trailer parks, skyscrapers, the Mississippi River, or the Dallas Cowboy cheerleaders can’t stop tornadoes.
One other reason why the perception may have spread that tornadoes don’t hit big cities is that many of the densest population centers, such as the Washington, D.C.–to–Boston and the San Diego–to–San Francisco corridors, are outside of “tornado alley.” Even so, tornadoes do sock big cities. Chuck Doswell, senior research scientist at the Cooperative Institute for Mesoscale Meteorological Studies, wrote us:
Tornadoes have recently hit the downtown areas of such cities as Salt Lake City, Utah; Miami, Florida; Nashville, Tennessee; and Fort Worth, Texas. In the Texas event, there were at least two tall buildings hit. One suffered enough damage that it was decided to demolish it rather than to repair the damage.
In 1970, in Lubbock, Texas, a violent tornado hit a large building with sufficient force to twist the structure. The only reason tall buildings are hit infrequently is that they don’t occupy very much space in this nation of ours. The more area covered, the greater the likelihood of being hit by a tornado.
Dr. T. Theodore Fujita, a tornado scientist who developed the scale commonly used to rank the severity of tornadoes, considered the role of skyscrapers and population density in thwarting the development of small tornadoes. The University of Chicago professor, who died in 1998, noted that since 1921, “practically no tornadoes occurred or moved across the central portion of Chicago.” Fujita theorized that perhaps the city’s higher temperature than surrounding areas (a phenomenon we discussed in our first book, Imponderables) and its man-made structures might be “acting against any tornado activity over the city.” Other major population centers that have been studied for tornado patterns, London and Tokyo, also seem to enjoy a relative dearth of small-tornado activity. But no expert seems to seriously think that even the highest skyscraper in the largest metropolis would scuttle an intense tornado from unleashing its fury.
Submitted by John Beton of Chicago, Illinois. Thanks also to Laura Gunn of Ames, Iowa.
Why Do Only Kids Seem to Get Head Lice?
Are there really insects so vile, so vicious, that they attack only innocent children? Maybe there are, but head lice are equal-opportunity pests. Anyone, young or old, white or black, male or female, is susceptible.
But that doesn’t mean that head lice don’t have preferences. According to the research of entomologists at Clemson University, every year 6 to 10 million people in the United States have head lice, with approximately three-quarters of them schoolchildren younger than twelve years old. If you’re a head louse, your target demographic is three to eleven. This is true all over the world: Recent studies in France, Denmark, Atlanta, Israel, and Korea all found that at least 3 percent of elementary school children were infected by lice or nits, some at twice that rate.
Lice aren’t demanding creatures. They just want to suck a little of your blood. All three varieties of lice (head, body, and “public”) feed on mammals, but head lice are found only on humans. A louse has six legs and is incapable of flying or jumping, so they cling to human hair and bite through the scalp, creating a tiny opening to suck the blood. Without a blood host, head lice are likely to survive for only a day or two.
As if having a louse on your head wasn’t lousy enough, the females have the nasty habit of laying eggs, or nits, in our hair, usually near the scalp, at a rate of about six to ten per day. Lice manufacture an insoluble cement that makes the eggs cling to our hair, so standard shampooing will not get rid of the nits. The egg hatches in about eight to ten days, and becomes an adult in another week to ten days. The adults only live for a month or so, but considering the rate at which they manufacture nits, that is of little solace.
We hope we will not be accused of nitpicking when we point out that lice eggs are often confused with dandruff or dried-up hairspray, as they are a similar color and size. But while dandruff and caked hairspray will brush out easily, nits usually can’t be extricated even if you go over it with a fine-toothed comb, although the closer the teeth in a comb are, the more likely you are to rid yourself of lice and nits.
While body lice tend to invade folks with poor hygiene, and “public” lice (the euphemism for “pubic lice” or “crabs”) are often sexually transmitted, there is no reason for social stigma about having head lice. Head lice are usually spread from person to person by direct contact, but they can also move to an object that has been used by an infected person, and transfer to another.
Head lice are perfectly content to reside on graybeards if given the chance, but kids provide more opportunities. Santa Monica, California, dermatologist Joseph W. Landau has seen several epidemics of lice in schools. Kids are less likely than adults to know whether they’ve been infested, and one kid can spread it to scores of others before treatment is provided.
More important, kids in school are constantly playing with one another, roughhousing, and touching. Girls tend to have more head lice than boys, probably because close contact is more socially acceptable, and they tend to share hats, combs, and hair accessories. Slumber parties can involve sharing more than s’mores.
Other perfectly innocent behaviors can cause louse problems. Kids are just the right height to spread lice in chairs, whether in a movie theater, a restaurant, an airplane, or most commonly, a school bus — their head hits the seat back, and the fleeing louse parks itself in the upholstery. The next person who sits in the chair is likely to find a new blood-sucking pal. Lying on a rug after an infected person has occupied the space makes you an equally compelling target. Parents of infected kids are just as susceptible to attracting head lice, and sometimes they succumb, but the parents are likely to take preventative measures, such as medicated shampoos, once they know their offspring has lice. If they don’t know about their progeny’s condition, and happen to use a towel with which their infected child dried his or her hair, they will be lousy with lice.
Although head lice are annoying, they are not particularly dangerous. In fact, the harshness of some of the remedies can be worse than the itching and occasional resultant rashes and infections that arise from scratching. Probably because of the social stigma of other kinds of lice, schools sometimes overreact when there is an infestation, and send parents a warning when even one child is known to be infected. Richard J. Pollack, of the Harvard School of Public Health, rails against the prevalent “no-nits” policy of many schools in which infected children are automatically sent home until nit-free. Pollack’s experience with samples sent in for diagnosis is that even among those that contained real louse eggs, “many were comprised solely of hatched or dead eggs; thus no treatment would be warranted.” In a few cases, courts have ordered child custody be taken away from parent
s who failed to eliminate infestations.
Back in the day when a certain master of Imponderability was in grade school, about the worst thing that your enemy could say about you was that you had “cooties.” Perhaps we are no more enlightened today.
Submitted by James Gleick of Garrison, New York.
Why Are Wells Round?
Next time you go swimming in a pool, please note that large quantities of water are quite capable of being held in rectangular receptacles, square ones, and even trapezoidal ones. But if you try constructing a trapezoidal pool, you’ll wish you were building a round one. Most wells are round because fashioning a round well is easier than building other shapes. And in this case, easier means cheaper. Kevin McCray, of the National Ground Water Association, wrote to Imponderables:
Water wells are constructed by means of specially designed machines or rigs that drill into the earth to encounter productive water-bearing formations. Some drilling machines work by lifting, turning, and dropping a long chisel-shaped tool, which forms a round hole by cutting up the rock or other earth materials. Another type of water well drill rotates a bit fixed to the lower end of a steel pipe called the drill pipe or rod.
Round wells have an illustrious history, dating back to the Chinese about 4,000 years ago, and to some extent, modern construction methods are just an automated version of what workers did by hand millennia ago, as McCray explains:
The Chinese developed a drilling method now known as the cable tool percussion method. Using bamboo tools, they were able to drill wells of up to 3,000 feet deep, although the deepest holes sometimes took two or three generations to complete. Cable tool drilling operates by repeatedly lifting and dropping a heavy string of drilling tools into the borehole, turning slightly with each stroke.
While cable tool drilling is still widely practiced, probably most boreholes are constructed by use of the direct rotary drilling method. The borehole is drilled by rotating a bit fixed to the lower end of a drill rod. Cuttings of rock and soil are removed from the borehole by continuous circulation of a drilling fluid as the bit penetrates the formation.
The turning action of either the cable tool method or direct rotary method assures that a round, straight hole will be constructed. While it might be possible to push or pound a square hole into the ground, the method would be limited by its impracticality. Virtually all water wells constructed in developed nations are drilled, not dug.
The occasional square well can be found, as McCray implies, mostly in undeveloped nations. Wells have a nasty habit of caving in. The best defense against a cave-in is lining the inside of the well. Shifting of the earth, severe weather, or earthquakes can cause caveins, but at no time is the danger greater than during the construction of the well itself. The only obvious reason to construct a square or rectangular well, unless there are space or aesthetic considerations, is because of a lack of lining materials that can be curved to fit a round well. In poor countries, flat wood boards are sometimes used for lining, despite wood’s obvious inappropriateness for holding water, and anyone poor enough to use untreated wood to line a well is unlikely to have the tools necessary to form the lining to fit a round well.
Submitted by Kathyrn Bennett of Yarmouth, Maine.
Why Are Some People Double-Jointed?
Here at Imponderables Central, the entire staff is unable to touch our toes without bending at our knobby knees. How can the human pretzels that perform for Cirque du Soleil place their legs behind their heads and play “Chopsticks” with their toes?
Medical authorities are quick to assert that flexible people have no more joints than mere mortals. As Timothy N. Taft, director of sports medicine at the University of North Carolina at Chapel Hill, wrote us:
The increased mobility is caused by laxity or looseness of the ligaments and the capsule that normally provide stability to the joint. The supporting structures that normally limit joint motion are elongated or more flexible than usual, thus the increased motion — usually in an unusual direction. This laxity can occur as a result of congenital looseness or it may follow an injury.
Taft portrays hypermobility as more of a curse than blessing; orthopedists are far more likely to see patients complaining about this condition than bragging about their flexibility. Several genetic conditions lead to hypermobility, most commonly Ehlers-Danlos syndrome, an inherited condition in which the collagen (the protein that reinforces the structure of the joints) is hyperelastic. Those with Ehlers-Danlos syndrome often have other unpleasant side symptoms, including joint pain, osteoarthritis, and stretchable skin — the so-called rubber men in circus sideshows usually have Ehlers-Danlos.
Collagen is the key component in cartilage, which provides padding between bones. The more flexible your cartilage is, the more flexible you will tend to be. Children’s cartilage is especially elastic, which is why pre-adolescent boys and girls are capable of twisting and folding their limbs in gymnastics; as we age and hormones kick in, the cartilage hardens along with bones, and most of us lose flexibility.
The majority of people that we might offhandedly call “double-jointed” do not suffer from any medical condition. They most likely possess supple collagen and proportionately longer discs than the vertebrae they separate. Shallow sockets, smoother bone ends, and especially flexible ligaments also can contribute to hypermobility. Needless to say, regimens of stretching will enhance a predisposition toward flexibility.
Even if “double-jointed” is a misnomer anatomically, some partisans have embraced the term. The Web site of the Halston Gymnastic Club has a “Double Jointed Page” (http://www.hgc.mcmail.com/) that argues that the Oxford English Dictionary endorses the concept (the fifth definition of “double” in the Shorter Oxford English Dictionary is: “Fold…so as to bring the two parts into contact, parallel; bend (the body), especially into a stooping or curled-up posture….”). The site disdains the use of “hypermobility” because the prefix “hyper” is used to signify “too much.”
Ironically, while the general population is striving to become more flexible, the “double-jointed” often don’t take advantage of their attributes:
Joint problems caused by not exercising joints properly are the scourge of the general population, and much emphasis is placed on the therapeutic benefits of stretching exercises for everybody. Those with unusually good flexibility will gain little from these routines because the exercises designed for the average person will not provide the range of movement to exercise their joints through their natural range. Whatever your natural range of joint flexibility, if you do not use it, the joint will degenerate.
To folks with serious genetic hypermobility, extreme flexibility isn’t necessarily a gift, as their full range of motion sometimes sends their bones and ligaments to places that joints were not meant to support, while others derive a paycheck from their “double-jointedness.”
Submitted by Debra Allen of Wichita Falls, Texas.
Why Do You Sometimes Find Ice in the Urinals in Men’s Bathrooms?
We were a little surprised when a woman posed this Imponderable, but Judith Dahlman came prepared with a rationalization:
In my waitress days, the restaurant where I worked had a big bin of ice right at the bar, where the waiters scooped the ice for drinks, as set-ups for the bartender to pour the booze or to fill up their own glasses with soft drinks. A metal scoop was included and you were supposed to use it, but waiters in a hurry often scooped the ice with the glass itself. This inevitably led to broken glasses, obviously a health hazard, what with pieces of glass now amid the ice cubes. Waiters were instructed to immediately lay a bar rag over the ice, as a signal to the other waiters not to use the ice. The busboy would then empty the bin, which would be washed out with water. New ice would be put in the bin.
My husband Paul’s response was: “So that’s why you sometimes see a big load of ice in a urinal?” I admit that I have only rarely seen this phenomenon, probably because most busboys are male, and they have free access to
the men’s rest rooms.
In my waiter days, I never thought of where the busboy dumped the ice, but the urinal is probably the safest, since if you threw it out the back door, some unsuspecting animal or stupid human might be endangered.
We talked to many restaurateurs and bartenders about this Imponderable, and found many that admitted to using urinals as dumping grounds for contaminated ice. Toilets, sinks, alleys, and the street were all favorite burial grounds for unwanted ice. Dumping ice mixed with broken glass anywhere in a public bathroom doesn’t seem smart; most bars and restaurants try to melt the ice with hot water in a sink or service bin and then throw the glass in the garbage. But ice is more often rendered unusable by spilled drinks or small pieces of food — both can easily be flushed away.
But we suspected more was at work. Most urinals are not large enough to hold the volume of ice held in bins behind bars. We’ve also seen ice put in urinals in rest rooms in gas stations without air conditioning, especially in the desert. Said bathrooms have a tendency to, let us be kind, not be fragrance free. We side with Gunnar Baldwin, senior national accounts manager of urinal manufacturer TOTO, USA, who wrote us:
The ice is put there to act as an automatic flushing system. As urine melts the ice, enough water is produced to help the urine siphon out of the trap within the urinal. Of course, the melting rate is proportional to the surface area of the ice, so crushed ice works better than larger cubes.
It also has the benefit of preventing splashing and reducing odor. Cold urine does not emit as much odor! But the main purpose is to melt enough ice to carry the urine down the drain.
Do Elephants Jump? Page 21