Submitted by the guy in the shower, New York, New York.
Why Do Pigeons Make a Whistling Sound When They Take Off in Flight?
Those aren’t pigeons’ voices but rather their wings you are hearing. Bob Phillips, of the American Racing Pigeon Union, told Imponderables that we are hearing the sound of air passing through feathers that are spread wide for acceleration, beating faster for lift, and spread wide for takeoff. Although we tend to associate this kind of high-frequency noise with hummingbirds, many birds produce similar tones, not unlike the sound of the wind whistling through the branches of trees.
Submitted by Martin C. Farfsing of Redwood City, California.
To prove the wholesome, family orientation of our readership, we can point to a surprising cluster of Imponderable obsessions about the subject of milk. Perhaps not the sexiest topic, but certainly among the most nutritious.
What’s the Difference Between Skim and Nonfat Milk? And How Do They Skim the Fat from Whole Milk?
Don’t believe it if anyone tells you there is any difference whatsoever. By law, skim milk and nonfat are the same: containing less than 0.5 milkfat content. (The milk solids that are not fat must equal or exceed 8.25 percent.) In practice, all the fat possible is eliminated from the product.
Any nonfat (or lowfat) milk that is shipped interstate must contain added vitamin A. Most of the vitamin A content in milk is contained in the milkfat. Most manufacturers add enough to equal the amount of vitamin found naturally in whole milk.
How do they separate the fat from whole milk? Our favorite dairy consultant Bruce Snow, explains:
When milk comes from old Bossy, it contains somewhere between 3 to 4 percent butterfat content (sometimes a percentage point more from cows like Guernseys and Jerseys). To obtain true skim milk, a machine called a “separator” is used. It whirls the milk around, and because the fluid and the butterfat content have different weights, centrifugal force separates the two ingredients into skim milk and cream. The cream is used to make butter, ice cream, whipped cream, etc.
Submitted by Herbert Kraut of Forest Hills, New York.
Why Does Some Lowfat Milk Contain One Percent Fat and Other Lowfat Milk Contain Two Percent Fat?
As we just learned, most cows naturally produce milk containing from 3 to 5 percent butterfat. In most states, “whole” milk is defined as milk with at least 3.25 percent butterfat. Lowfat milk, then, is any milk that falls between.5 percent (skim or nonfat) and 3.5 percent (whole).
In practice, 1 and 2 percent milks are the most popular types of lowfat milk. In fact, we’ve never seen 3 percent milk, probably because that one half a percent would not reduce the calorie count enough to appeal to dieters.
Many consumers were sick of looking at what looked like water residue on the bottom of their cereal bowls; lowfat has been steadily gained market share for the last thirty years, stealing customers from both former skim milk and whole milk drinkers. In fact, lowfat milks outsell “whole” milk in most parts of the country. Two percent seems to be winning the cash register battle against 1 percent, but not without a cost to the waistline; that extra percent of fat adds about thirty calories to each cup of 2 percent lowfat milk.
Submitted by Herbert Kraut of Forest Hills, New York.
Why Do Plastic Gallon Milk Containers Have the Counter-Sunk Dips on Their Sides?
According to Michelle Mueckenhoff, technical services manager of the Dairy Council of Wisconsin, and every other dairy expert we bored with this question, those dips are there to provide structural support and strength to the container. And nothing more.
Submitted by Daniell Bull of Alexandria, Virginia.
Why Aren’t “Green Cards” Green?
We’ve never been ones to make cheap, easy jokes about our federal government. Sure, there is excess and incompetence in any large conglomeration of workers. We were confident that there was a perfectly brilliant strategy behind naming what are most often blue cards “green cards.”
So we contacted the Immigration and Naturalization Service and were lucky enough to come in contact with Elizabeth A. Berrio, chief of the INS Historical Reference Library, who specially prepared a document to share with Imponderables readers. And we’re happy to conclude that there is a totally logical reason why green cards aren’t green. Well, would you believe semilogical?
What we know as a “green card” came in a variety of different colors at different times in its history. We still refer to them as “green cards” for the same reason dismissal notices are called “pink slips,” sensationalized news is called “yellow journalism,” and intended distractions are called “red herrings.” In each case, an idea was originally associated with an actual item of the respective color. A Lawful Permanent Resident (LPR) alien living in the United States may carry a card that is not green, but refers to it as a “green card.” The alien does so because the card bestows benefits, and those benefits came into being at a time when the card was actually green.
The green card is formally known as the Alien Registration Receipt Card, from I-151 or I-551. The first receipt cards were from AR-3 and were printed on white paper.
This receipt proved that a noncitizen of the United States did register, but it didn’t indicate whether the alien was legal or illegal. After World War II, when a new wave of immigration began, the INS started issuing different documents to indicate whether an alien was a visitor, a temporary resident, or a permanent resident.
This method…helped to identify the immigration status of each alien. Thus, the small, green I-151 had immediate value in identifying its holder as a LPR, entitled to live and work indefinitely in the United States. As early as 1947, LPRs protested delays in processing their I-151s, complaining that employers would not hire them until they could prove their permanent resident status.
In 1951, the green cards became even more valuable:
regulations allowed those holding AR-3 cards to have them replaced with a new form I-151 (the green card)…only aliens with legal status could have their AR-3 replaced with an I-151. Aliens who applied for replacement cards but could not prove their legal admission into the United States, and for whom the INS had no record of legal admission, did not qualify for LPR status and might even be subject to prosecution for violation of U.S. immigration laws.
By 1951, then, the green Alien Registration Receipt Card Form I-151 represented security to its holder. It indicated the right to permanently live and work in the United States and instantly communicated that right to law enforcement officials. As a result of the card’s cumbersome official title, aliens, immigration attorneys, and enforcement officers came to refer to it by its color. The term “green card” designated not only the document itself, but also the official status desired by so many legal nonimmigrants (students, tourists, temporary workers) and undocumented (illegal) aliens. The status became so desirable that counterfeit form I-151s became a serious problem.
To combat document fraud, the INS issued nineteen different designs of the I-151 between its introduction in the 1940s and its complete revision in 1977. One alteration to the design in 1964 was to change the color of the card to blue. The 1964 edition was a pale blue. After 1965, it was a dark blue. Regardless of color, the I-151 still carried with it the benefits indicated by the term “green card,” and those who wanted, obtained, issued, or inspected I-151s continued to refer to it by that name.
The INS has not given up on foiling counterfeiters. In 1977, it issued a machine-readable receipt card and keeps experimenting with new colors, including such unlikely choices as pink and pink-and-blue. But Berrio is resigned: “Despite these changes in form number, design, and color, the INS document which represents an alien’s right to live and work in the United States will probably always be known as a “green card.”
Submitted by Eileen Joyce of Texarkana, Texas.
When Do Kids Turn into Goats?
When they have their bar mitzvah?
But seriously, folks, though it may have been submitted by a
“kid” in Mary Helen Freeman’s Aiken, South Carolina, Millbrook Elementary School class, this Imponderable was sufficient to stump most of the goat authorities we contacted. For example, John Howland, secretary-treasurer of the American Goat Society, was modest enough to admit he wasn’t sure of the answer and was kind enough to write to several other experts. They couldn’t reach a definitive consensus: Some argued for four months; others for six months; and some maintained that kids didn’t turn into goats until they were old and large enough to breed.
Rowland then consulted the text Raising Milk Goats the Modern Way, by Jerry Belanger:
Mr. Belanger said that kids are ready to breed when they are about seven months old and weigh about seventy-five to eighty pounds. In his glossary, he says: “Kid: a goat under one year of age.”
Bonnie Kempe, secretary of Alpines International, concurred with Rowland that definitions of “kid” vary from expert to expert, but she did offer what she thought was the most popular definition:
Baby goats are called “kids” the first year of their life. The second year they are called “yearlings,” and after age two either “does” or “bucks.”
Still, some veterinarians we spoke to felt that once a goat can breed and bear offspring, it is inappropriate to call mama or papa a kid.
Submitted by Ivy Moore of Aiken, South Carolina.
Why Do Baked Hams Usually Have a Checkerboard Pattern Along the Top?
Most of the time, the checkerboard pattern is created by the cook scoring the top of the ham for purely decorative reasons. Unlike the brittle skin of a turkey, it is quite easy to cut superficial slices in ham, and many cooks find the pattern visually pleasing.
Chances are, though, that scoring of ham was originally initiated for more practical reasons. According to pork experts at the National Live Stock & Meat Board,
…this process probably began with the old-style hams that had more fat. The scoring, or slicing, of the surface may have been done as a way to allow the fat to drain during cooking. Hams today are much leaner, so the scoring may be done simply for visual reasons.
Since the hams are so lean, it is important not to score too deep. This will cause the natural juices to run out and make the ham very dry.
Robin Kline, director of consumer affairs at the Pork Information Bureau of the National Pork Producers Council, concurs with the “decorative” theory and adds that many other decorations are used routinely to embellish the cooked ham:
One might also stud the top of the ham with cloves. You’ve probably seen pineapple rings, maraschino cherries, and pecan halves. Different strokes…
Occasionally you will buy a ham with a checkerboard pattern already emblazoned in the animal. These are the imprints of the netting used to hold and shape the meat during curing. The nets may be made of rubber-elastic, plastics, or natural fibers. According to Anne Tantum, of the American Association of Meat Processors, nettings (also known as “stockings”) are used particularly often in the curing of boneless hams, which tend to bulge if left to cure without “undergarments.”
Ham stockings come in many configurations, but most often the resultant patterns are square, rectangular, or diamond-shaped. And although these designs were probably the last thing on the minds of the ham processors, net-created patterns save the cook the not particularly time-consuming task of scoring the ham to create a little ocular razzle-dazzle.
Submitted by Wayne Rhodes of Deerfield, Illinois.
What Is the Emblem on the Pittsburgh Steelers’ Helmets? And Is There Any Particular Reason Why the Pittsburgh Steelers Are the Only NFL Team to Have Their Logo on Only One Side of Their Helmets?
We thought this Imponderable might be a little obscure to include here, but when we found out that the Pittsburgh Steelers public relations department developed a form letter expressly to answer it, we realized that football fans must be burning to know all about the Steelers’ helmet emblem. So here’s the form letter:
The emblem, called a steelmark, was adopted in 1963 and is the symbol of the Iron and Steel Institute. There is not a special reason as to why the emblem is only on the right side. That is the way the logo was originally applied to the helmet, and it has never been changed.
So many NFL teams redo their helmet design at the drop of a hat, so to speak, that our guess is that in 1963, the Steelers were not alone in their single-sided emblem configuration.
Submitted by Sue Makowski of Depew, New York. Thanks also to Thomas Ciampaglia of Lyndhurst, New York.
Why Did the Rabbit Die When a Pregnant Woman Took the “Rabbit Test”?
Ever since we were babes (as in “babes in the woods,” not as in “hot babes,” of course), popular culture, especially bad jokes, has informed us that “the rabbit died” meant “pregnant.” But we always wondered why a rabbit had to die in order to diagnose a pregnancy. So we were gratified when this Imponderable was sent in by a reader who happens to be a physician. If he didn’t know, maybe we weren’t so dim-witted for not knowing ourselves.
At its height of popularity, the rabbit test would be administered to women after they missed two consecutive menstrual periods. A small sample of urine was injected into a female rabbit. But why urine? Why a rabbit?
Urine has been used to diagnose pregnancies as far back as the fourteenth century B.C. by the Egyptians. They poured urine on separate bags of barley and wheat. If either grain germinated, the woman was pregnant. They believed that if the wheat germinated, it would be a boy; the barley, a girl. There were probably a lot of unused cribs and miscolored baby clothing in ancient Egypt.
The early Greek physicians also dabbled in urine analysis for the detection of pregnancy. In his book Obstetric and Gynecologic Milestones, Dr. Harold Speert notes that urine analysis was a particular favorite of medieval English quacks, often called “piss-prophets,” who claimed to diagnose just about any malady from indigestion to heartache. Reaction against these charlatans was so strong that urinary diagnosis was rejected during most of the eighteenth and nineteenth centuries by reputable physicians.
But in 1928, two German gynecologic endocrinologists, Selmar Ascheim and Bernhard Zondek, announced a urinary test that could be replicated easily throughout the world. They injected urine into five infant mice. Ascheim and Zondek explained why they needed five mice:
Five infantile mice are used for each urine examination. The urine must be tested on several mice because an animal may die from the injection, but more important because not all animals react alike…. The pregnancy reaction is positive if it is positive in only one animal and negative in the others.
The A-Z test, as it has become known, is still the basis for all urine-based pregnancy exams, including the rabbit test.
So why the switch from mice to rabbits? Dr. T.E. Reed, of the American Rabbit Breeder’s Association, explained the advantages of rabbits, and we promise to get through this discussion with no cheap “breeding like rabbits” jokes.
Most mammals have “heat” cycles, when females are receptive to the male. These cycles are physiologically based and are accompanied by changes in hormonal levels. The ovary is affected by the estrogenic hormone, the animal ovulates, and then is receptive to the male for breeding.
But the domestic rabbit is different, as Reed explains:
The rabbit does not ovulate until it has been mated with the buck. The rabbit then ovulates ten hours later and the sperm that was deposited during the copulation process will fertilize the ovum.
The uniqueness of domestic rabbits’ physiology of reproduction is what allowed the pregnancy tests for humans to be utilized. Virgin does were used in the “rabbit test.” Because researchers used does that had not been mated, the ovaries of the animal had never produced follicles from the ovaries.
Rabbit tests proved to be faster and more reliable than the original A-Z test.
But why did a pregnant woman’s urine kill the rabbits? Ah, the nasty little secret: The test itself did not kill the rabbits, as Reed explains:
The inventor of the rabbit test, Maurice Harold Friedman, injected the rabbits three times a day for two days, but later practitioners simplified the procedure to one injection and a twenty-four-hour waiting period. Through trial and error, researchers later found that it was not necessary to kill the rabbit at all, and one rabbit was used for several tests, after allowing the ovaries to regress after a positive result.
Although the theory behind the rabbit test was perfectly sound, one problem in reliability persisted: The rabbits chosen weren’t always virgins, resulting in false positives. More sophisticated tests were developed without needing animals at all. But even modern laboratories, like the home pregnancy kits, measure the same hormone levels that Friedman, Ascheim and Zondek, and maybe even the piss-prophets and ancient Egyptians predicted pregnancy by.
How Does Aspirin Find a Headache? Page 7