Most of the demand for new money comes from banks. When a bank receives more checks to cash than it can comfortably accommodate with its cash on hand, the bank orders new money from one of the twelve Federal Reserve Banks. Of course, the bank doesn’t get the new money for free; it uses a special checkbook to order new cash. When a bank has excess cash, it can deposit money into an account at the Federal Reserve Bank to offset its withdrawals.
What happens when the Federal Reserve Bank itself runs out of coins or notes? It places an order with the U.S. Mint for new coins or the Bureau of Engraving and Printing for the new currency. So demand from individual banks, funneled through a larger “distributor”—a Federal Reserve Bank—is responsible for the decision to issue new currency.
The average life-span of a dollar bill is fifteen to eighteen months. Larger denominations tend to have a longer life because they are circulated less frequently. The perishability of paper notes is the second major factor in calculating the requirements for new currency. In 1983 alone, the twelve Federal Reserve Banks destroyed more than 4.4 billion notes, worth more than $36 billion. The constant retirement of defective bills explains why almost one out of every four notes the Federal Reserve Bank sends to local banks is a newly printed one.
Every time a Federal Reserve Bank receives currency from a local bank, it runs the notes through high-speed machines designed to detect unfit currency. The newest machines can inspect up to sixty thousand notes per hour, checking each bill for dirt by testing light reflectivity (the dirtier the note, the less light is reflected) and authenticity (each note is tested for magnetic qualities that are difficult for counterfeiters to duplicate).
Notes valued at $100 or less are destroyed by the local Federal Reserve Bank. Unfit bills used to be burned and processed into mulch (we kid you not), but they are now shredded and compressed into four-hundred-pound bales. Most of these bundles of booty are discarded at landfills. Federal Reserve notes in denominations of $500 or more are canceled with distinctive perforations and cut in half lengthwise. The local Federal Reserve Bank keeps the upper half of each note and sends the other half to the Department of Treasury in Washington, D.C. When the Treasury Department verifies the legitimacy of the notes, it destroys its halves and informs the district bank that it may destroy the upper halves.
Coins have a much longer life in circulation, but the Mint still produces more than 50 million coins a day (compared to “only” twenty million notes printed per day). A U.S. Mint official told us that shipping coins across country is not a trivial task logistically—five-hundred-thousand pennies, for example, are a tad bulky. Huge tractor-trailer trucks, up to 55 feet in length and 13 1/2 feet high, are used to transport coins from the Mint to Federal Reserve Banks. Dimes, quarters, and half dollars are transported by armored carriers.
The demand process for coins works the same way as for paper notes. Although the Mint has learned that seasonal peaks run true from year to year (the demand for coins goes up during prime shopping seasons, such as Christmas), the Mint yields to the demands of its constituent Federal Reserve Banks.
Submitted by Hugo Kahn of New York, New York.
What Is the Purpose of that Piece of Skin Hanging from the Back of Our Throat?
No, Kassie Schwan’s illustration to the contrary, the purpose of that “hanging piece of skin” is not to present targets for cartoon characters caught inside other characters’ throats. Actually, that isn’t skin hanging down, it’s mucous membrane and muscle. And it has a name: the uvula.
The uvula is a sort of anatomical tollgate between the throat and the pharynx, the first part of the digestive tract. The uvula has a small but important role in controlling the inflow and outflow of food through the digestive system. Dr. William P. Jollie, chairman, Department of Anatomy, the Medical College of Virginia, explains: “The muscle of both the soft palate and the uvula elevates the roof of the mouth during swallowing so that food and liquid can pass from the mouth cavity into the pharynx.”
Dr. L.J.A. DiDio, of the Medical College of Ohio, adds that the uvula also helps prevent us from regurgitating our food during swallowing. Without the uvula, some of our food might enter the nasal cavity, with unpleasant consequences.
Submitted by Andy Garruto of Kinnelon, New Jersey.
Why Don’t Birds Tip Over When They Sleep on a Telephone Wire?
A telephone wire, of course, is only a high-tech substitute for a tree branch. Most birds perch in trees and sleep without fear of falling even during extremely windy conditions.
The secret to birds’ built-in security system is their specialized tendons that control their toes. The tendons are located in front of the knee joint and behind the ankle joint. As it sits on its perch, the bird’s weight stretches the tendons so that the toes flex, move forward, and lock around the perch.
Other tendons, located under the toe bones, guarantee that a sleeping bird doesn’t accidentally tip over. On the bottom of each tendon are hundreds of little projections. These fit perfectly into other ratchetlike sheaths. The body weight of the bird pressing against the telephone wire (or tree branch) guarantees that the projections will stay tightly locked within the sheaths.
Barbara Linton, of the National Audubon Society, adds that while this mechanism is most highly developed in perching birds and songbirds, many other birds do not perch to sleep. They snooze on the ground or while floating on water.
Submitted by Dr. Lou Hardy of Salem, Oregon. Thanks also to Jann Mitchell of Portland, Oregon.
Why Is It Sometimes Necessary to Stroke a Fluorescent Lamp to Get It to Light?
All fluorescent bulbs require a ground plane to start. If the fluorescent lamp is inside a metal fixture, any piece of metal, such as the reflector, can serve as a ground plane. Richard H. Dowhan, manager of Public Affairs for GTE Products Corporation, told Imponderables that the closer the ground plane is to the tube, the easier it is to start the fluorescent. “Placing your hand on the tube or stroking it creates a very effective ground plane.” Magicians have been lighting “naked” fluorescent bulbs for quite a long time by serving as the ground plane.
But most of us aren’t magicians, and most of us use fluorescent lamps inside of metal fixtures. Why do the lamps usually light with a flick of the switch at some times and then other times require a little massage? J. Robert Moody, of General Electric’s Lighting Information Center, was kind enough to supply an answer that doesn’t require a physics degree to understand.
Under normal conditions, fluorescent lamps should light without difficulty, with the electric current flowing inside the fluorescent tube. But if the lamp has a combination of a light coating of dust and a small amount of moisture from the air, the coating will allow “some of the electric current to flow on the outside of the tube, and the current on the outside of the bulb will prevent the lamp from lighting. Under this condition, stroking the tube will interrupt the flow of current on the outside of the tube and cause the light to come on.”
Submitted by Harold J. Ballatin of Palos Verdes, California.
Why Is There an Expiration Date on Sour Cream? What’s the Matter, Is It Going to Get More Sour?
We’ve gotten this Imponderable quite often on radio interviews, usually from smug callers sure that expiration dates are a capitalist plot to force us to throw away barely used sour cream. But mark our words: if you think sour cream is tart when you open it, just leave it in the refrigerator too long and taste the difference. As the expiration date on sour cream becomes a dim memory, bacteria acts upon the sour cream, making it unbearably tart. Given enough time, mold will form on the sour cream, even if it is properly refrigerated.
Sour cream has about a month-long life in the refrigerator. Wait much longer and we’ll bet that you won’t want to test just how sour cream can get. If you think we’re wrong, there’s one way to find out for sure.
Go ahead and taste it. Make our day.
Who Translates the Mail When a Letter Is Sent to the United States from a Foreign
Country that Uses a Different Alphabet?
If the United States Postal Service has problems sending a letter across town in a few days, we wondered how they contended with a letter sent to Nebraska from a remote village in Egypt. Does every post office hire a staff of linguists to pore over mail and route it in the right direction?
No, not every post office. But the USPS does employ linguists at their International Exchange Offices, located at the major ports (New York, San Francisco, Miami, and Boston) where foreign mail is received. All mail is separated and sorted at these border points and sent on its merry way.
We contacted some foreign consulates to find out how they solved the problem of indecipherable mail. A representative of the Greek consulate told Imponderables that if foreign mail is written in one of the international languages, multilingual personnel have no problem sorting it. If no postal worker can translate an address, the postal service will likely do what we did—call the embassy or consulate of the country of the sender and hope for the best.
Submitted by Charles F. Myers of Los Altos, California.
Why Do Roaches Always Die on Their Backs?
We couldn’t believe that three readers actually had experienced the good fortune to see a dead roach and had torn themselves away from the subsequent celebration long enough to note the posture of the deceased insect. But we trudged on nevertheless, contacting entomologists who actually get paid to study stuff like this.
Professor Mary H. Ross, affiliated with Virginia Polytechnic Institute and State University, told Imponderables that when a roach dies, its legs stiffen and the cockroach falls on its side. Because most roaches have a flattened body form with narrow sides, the momentum of the fall rolls them onto their backs.
John J. Suarez, technical manager of the National Pest Control Association, adds that small cockroaches, such as the German and the brown-banded, are more likely to die on their backs. Larger cockroaches with lower centers of gravity, such as the American and the Oriental, occasionally die face down.
Needless to say, we can’t guarantee the position of dead roaches contained in traps. Maybe the lifeless occupants of Roach Motels lie perfectly prone. Unfortunately, there is only one way to find out and only entomologists have the stomach for it. Please don’t try to verify this at home!
Submitted by Gloria Stiefel of Orange Park, Florida. Thanks also to Irma Keat of Somers, New York; and Gregg Hoover of Morgan Hill, California.
Why Does Warmth Alleviate Pain?
A caller on Tom Snyder’s radio show posed this Imponderable. We had no idea of the answer, but it was surprising that so many physicians we spoke to didn’t know the answer either.
We finally got the solution from Daniel N. Hooker, Ph.D., coordinator of Physical Therapy/Athletic Training at the University of North Carolina at Chapel Hill. His answer included plenty of expressions like “receptors,” “external stimuli,” and “pain sensors.” So let’s use an analogy to simplify Hooker’s explanation.
If a pneumatic drill is making a ruckus outside your window, you have a few choices. One is to do nothing, which won’t accomplish much until the drill stops. But another option is to go to your stereo and put on a Led Zeppelin record at full blast. The pneumatic drill is still just as loud—you may still even be able to hear it. But the music will certainly distract you (and for that matter, your next-door neighbors as well), so the drilling doesn’t seem as loud.
Hooker emphasizes that most of us associate warmth with pleasant experiences from our youth. By placing heat on the part of our body that hurts we stimulate the sensory receptors, which tell our brain that there has been a temperature change. This doesn’t eliminate the pain, but the distraction makes us less aware of the pain. As our body accommodates to the high temperature, we need fresh doses of warmth to dampen the pain. When we receive the renewed heat treatment, we expect to feel better, so we do.
Why Can’t We Use Both Sides of a Videotape like We Do with an Audio Tape?
Don French, chief engineer of Radio Shack, is getting a little testy with us: “If you keep using me as a consultant on your books, we are going to have to start charging for my service!”
We have read all of the bestselling business management books. They all reiterate that most people aren’t motivated by higher pay but by recognition of their effort and accomplishments. So to you, Don French, we want to acknowledge our heartfelt appreciation for the efforts you have expended in educating the American public on the wonders and intricacies of modern technology in our contemporary culture of today. Through your efforts, our citizens will be better equipped to handle the challenges and complexities of the future.
But not one penny, bub.
Luckily, Mr. French couldn’t resist answering this Imponderable anyway.
It turns out that even though some audio cassette recorders require the tape to be flipped before recording on the other side, the recorder doesn’t actually copy on both sides of the tape. It copies on the top side of the tape in one direction and the bottom in the other direction.
On videotapes, the audio is also recorded on a small portion of the top side of the tape. But the video, with a much higher frequency requirement and slower recording speed, needs much more room to copy, and is recorded diagonally on most of the remaining blank tape.
Submitted by Jae Hoon Chung of Demarest, New Jersey.
Why Are the Toilet Seats in Public Restrooms Usually Split Open in the Front?
This has become one of our most frequently asked Imponderables on radio shows. So for the sake of science and to allay the anxiety of unspoken millions, here’s the, pardon the expression, poop on a mystery whose answer we thought was obvious.
Try as they might, even the most conscientious janitors and bathroom attendants know it is impossible to keep a multiuser public toilet stall in topnotch sanitary condition. Let’s face it. Pigs could probably win a slander suit from humans for our comparing our bathroom manners to theirs. Too many people leave traces of urine on top of toilet seats. Men, because of a rather important physiological distinction from women, particularly tend not to be ideally hygienic urinators, but most sanitary codes make it mandatory that both male and female toilets contain “open-front” toilet seats in public restrooms. In fact, at one time, “open-back” seats were mandated as well, but the public wouldn’t stand (or sit) for them.
If they are more hygienic, why not use open-front toilet seats at home? The answer is psychological rather than practical. An open-front seat would imply to the world that one’s bathroom habits were as crass as those employed by the riffraff who use public restrooms. Still, we would think that open-front toilet seats in home bathrooms might lessen the number of divorce-causing arguments about men keeping the toilet seats up.
Submitted by Janet and James Bennett of Golden, Colorado. Thanks also to Tom Emig of St. Charles, Missouri; Kate McNeive of Scottsdale, Arizona; and Tina Litsey of Kansas City, Missouri.
How Are the First Days of Winter and Summer Chosen?
This Imponderable was posed by a caller on John Dayle’s radio show in Cleveland, Ohio. John and the supposed Master of Imponderability looked at each other with blank expressions. Neither one of us had the slightest idea what the answer was. What did it signify?
We received a wonderful answer from Jeff Kanipe, an associate editor at Astronomy. His answer is complicated but clear, clearer than we could rephrase. So Jeff generously has consented to let us quote him in full:
The first day of winter and summer depend on when the sun reaches its greatest angular distance north and south of the celestial equator.
Imagine for a moment that the Earth is reduced to a tiny ball floating in the middle of a transparent sphere and that we’re on the “outside” looking in. This sphere, upon which the stars seem fixed and around which the moon, planets, and sun seem to move, is called the celestial sphere. If we simply extend the earth’s equator to the celestial sphere it forms a great circle in the sky: the celestial equator.
; Now imagine that you’re back on the Earth looking out toward the celestial sphere. You can almost visualize the celestial equator against the sky. It forms a great arc that rises above the eastern horizon, extends above the southern horizon, and bends back down to the western horizon.
But the sun doesn’t move along the celestial equator. If it did, we’d have one eternal season. Rather, the seasons are caused because the Earth’s pole is tilted slightly over 23 degrees from the “straight up” position in the plane of the solar system. Thus, for several months, one hemisphere tilts toward the sun while the other tilts away. The sun’s apparent annual path in the sky forms yet another great circle in the sky called the ecliptic, which, not surprisingly, is inclined a little over 23 degrees to the celestial equator.
Motions in the solar system run like clockwork. Astronomers can easily predict (to the minute and second!) when the sun will reach its greatest angular distance north of the celestial equator. This day usually occurs about June 21. If you live in the Northern Hemisphere and note the sun’s position at noon on this day, you’ll see that it’s very high in the sky because it’s as far north as it will go. The days are longer and the nights are shorter in the Northern Hemisphere. The sun is thus higher in the sky with respect to our horizon, and remains above the horizon for a longer period than it does during the winter months. Conditions are reversed in the Southern Hemisphere: short days, long nights. It’s winter there.
When Do Fish Sleep? Page 12