Do Elephants Jump?

by David Feldman

  2. It’s the Barometer, Baby!

  Before a rain, the barometric pressure falls. Fishermen believe that fish can sense the barometric change and get more aggressive. Captain John Leech, a full-time professional fisherman and bass guide, wrote to Imponderables:

  The study of weather will give us a bigger piece of the puzzle of fish behavior than any other single study…. After three days of any constant weather, the fish will start to become accustomed to the conditions and return to a normal activity. The passing of fronts is the change factor. Warm fronts are the fish-catching fronts. Cloudy weather, dropping barometer, south to west winds are the predominant conditions. Resident fish will move out from under the heavy cover to the edge and feed. The deep open-water fish will move to all breaks, even to the shallows to feed.

  What explains this behavior? Professor Bain confirms that fish can sense barometric pressure changes, and the most likely explanation for this gift is to allow them to sense when food might be difficult for them to acquire (such as when there is a storm). Instinctively, then, fish may sense a drop in barometric pressure as a time to start eating “while the getting is good.” Biologists don’t know for sure exactly how fish sense barometric changes, but one common theory is that the “lateral line,” a collection of hairlike structures along the flanks of most fish, is responsible. We know that fish use the lateral line to detect pressure waves from other fish to protect themselves when they are about to be attacked, even if they can’t see or smell the potential predator.

  At least one credible source minimizes the importance of barometric changes in affecting fish feeding behavior. B. C. Roemer, president of ScentHead, a company that manufactures artificial baits, writes:

  Can a fish notice this small change and has it anything to do with feeding (the bite)? I don’t know, nor does anyone else. I do know that just before a storm (and even in it) fish turn the bite on. This is a well-proven fact. But does a low barometer affect the fish’s body to trigger the bite? I don’t think so, assuming a bass is about at a 3-foot depth. Under normal swimming it would have to stay exactly at that level or the pressure from the water would increase or decrease a lot more than the small air-pressure change. So it’s reasonable to disregard barometer readings. Something else is going on to produce the bite.

  Roemer notes that a fish swimming even a few inches up toward the surface or lower toward the floor will feel a much greater change in pressure from their altitude than because of barometric fluctuations due to weather patterns. Mark Bain acknowledges the truth of Roemer’s assertion, but adds that fish may be able to sense the outside pressure changes independently, in a way that we do not understand.

  3. The Eyes Have It!

  The clearer the water is, the more fish act defensively. In his article in Field & Stream, Jack Kulpa notes this effect:

  Even the biggest largemouth bass feels exposed and vulnerable in direct sunlight. On the brightest days these fish burrow into weeds or head for deep, dark water where they are all but inactive and unapproachable. Yet as daylight fades with the approach of a storm, even big bass are lulled into a sense of security. When that happens, they may strike suddenly and unexpectedly.

  Mark Bain notes that rain tends to reduce water clarity. Although turbid water makes it harder for predators to attack, it also decreases a fish’s visual access to food. Many experts believe that fish learn when the water turns cloudy that they had better look for food fast, before a storm renders it too difficult to find and eat a proper meal. For the fisherman, this can be a mixed blessing. Says Bain:

  If the fish turn off from feeding, that will be bad. But if they’re hungry, they will tend to take bait more freely if it is presented directly in front of them.

  With rain comes clouds, and when there is a cloud cover, less ultraviolet light penetrates the water. Fish are sensitive to light and are more apt to feed when there is relatively less light in the water. This is probably a major reason why the presumed best times for fishing are early morning and late evening, when temperatures are cool — these are both times of reduced light above and below water. When it rains and the cloud cover darkens the sky and the water, the fish may be tricked into thinking that it is actually late evening. This theory is hard to prove — we were unable to get a fish to comment on or off the record.

  4. It’s the Water!

  A light rain aerates the water, which has the effect of naturally oxygenating the water in the same way that those little bubble machines do in an aquarium. Jack Kulpa notes that the combination of cooler water temperature and increased oxygen seems to give bass (and other fish) a burst of energy, sort of the fish equivalent of a cup of joe.

  In his book Keeper of the Stream, author Frank Sawyer notes that the water seems to come alive after rainfall, partly because flies hatch in profusion, possibly because of the aeration. If flies are hatching, fish are trying to eat them, and fisherman are trying to capitalize on their prey’s increased biting.

  5. Hear No Evil!

  Water is an excellent conductor of sound, so any noise generated will travel through the water. Johnny Hickman, an avid fisherman based in West Texas, shared a theory with Imponderables that posits that audio might be a key component in the answer:

  In a steady rain, the thousands of raindrops hitting the water will be pretty noisy underwater, providing a kind of “white noise” that will tend to hide man-made noises. Add to that the decreased visibility due to cloud cover and the constantly disturbed surface of the water and you get a situation that makes the fish less spooky.

  6. It’s the Humans, Stupid!

  Could the human psyche play a role in success in fishing? One authority, Lesley Crawford, writes in his book, The Trout Fisher’s Handbook,

  I haven’t come up with enough evidence to convince myself that fishing is better in the rain. One thing that I do know is the importance of confidence. If you think and are confident that fishing is better in the rain, then you will catch more fish because you expect to, and, as a result, probably fish better, too — which is, perhaps, the real reason that you are catching fish!

  But more than positive thinking might be involved. If it rains, less hardy (or less crazy) fishermen retreat to their campsites or automobiles (or nearby tavern) and there is less competition to catch fish, accounting for more success per active fisher. The fish may be more likely to feed when fewer humans are afoot and fewer boats are mauling the serenity of the water.

  Fishermen, with luck, are a little brighter than the average trout, and anglers have gained knowledge about the predictable habits of fish during rain. If fish are known to retreat to an isolated inlet when it rains, hardcore fishermen will brave the elements to drop lines there. If they know that a storm will cause fish to withdraw to the lower depths, then fishermen will cast lower than they normally would.

  THE DISSENTERS

  A minority, but a vocal one, isn’t so sure that fish do bite more when it rains, at least not consistently so. One group, the Forest Preserve of Cook County (Illinois), tabulated daily records of catches over a twelve-year period, from 1932 to 1943, with over 15,000 pounds of hook-and-line fish caught by its members.

  The group’s conclusion? There was a slight increase in catch rate when it rained at least one-half inch, but not at all on the days after. Surprisingly, bass bit almost twice as much when the water cleared up two or three weeks later, but it didn’t seem to matter whether the weather was fair or cloudy, from what direction the wind was coming, whether it was day or night, or whether the barometer was high or low, rising or falling. The group also found no significant difference between the catch rate of men versus women:

  During the entire twelve years, men averaged 3.25 pounds per day, while the women averaged 3.22 pounds. Of course, the men say they hooked a lot of big ones that got away.

  Others who have conducted more limited experiments have issued conflicting reports about the role of barometric pressure, cloud cover, temperature, and rainfall on biting patterns of fi
sh.

  All these different theories make our head spin, and since we can’t seem to catch fish in any environment other than a stocked pond, we identify more with the sentiments of “Mudcat,” a fishing hobbyist who preferred to theorize about the effects of rain upon humans, or at least one human:

  I know that rain sure makes me hungry. Just last weekend [during a rainstorm], I had eight tacos and two burritos in one sitting.

  Submitted by Professor Elizabeth Goldsmith of Tallahassee, Florida.

  Why Are We Instructed to “Remove Card Quickly” When We Swipe Our Credit Cards at the Gas Pump or Grocery Store?

  Your credit card face is full of all sorts of information — your name, your credit card number, the expiration date, the snazzy graphics, the name and address of the issuing bank, and the logo of the credit card company. But the machine that swipes your credit card cares not a whit about any of that stuff. All it lusts after is the information held in that thin, horizontal black stripe that runs across the back of the credit card. That stripe, known as a “magstripe” (short for “magnetic stripe”) contains tiny magnetic particles that can be magnetized so they each lie in one of two directions. These particles provide all the information that the bank, the oil corporation, or credit card company needs to haunt your next statement.

  Just as the binary data on a computer, ultimately, is a series of zeros and ones, so are these particles magnetized to be oriented on the magstripe. These little iron-based magnetic particles are only twenty-millionths of an inch long. Once the province of credit cards, magstripes can be found not only on ATM cards, but student identification cards, library cards, and office-machine user ID cards.

  The magstripe works on the basic principles of electromagnetism. Whenever a magnet moves, it generates an electrical field. If there is a metal wire (or other item that can conduct electricity) near the moving magnet, the motion will cause an electrical current to flow in the wire or other conductor. (The converse is also true: If you have an electric current flowing in a wire, the current will generate a magnetic field near the wire.)

  When you swipe the credit card by sliding it in and out at the fuel pump, the movement of that magnetic stripe across the “read head” (the part of the card-reading device that interprets the data held in the particles) creates a tiny electrical pulse. The read head is capable of distinguishing between pulses in the particle magnetized to represent a one, or the other particle magnetized in the other direction to represent a zero.

  The faster a magnet moves by a wire, the stronger the electrical current in the wire will be. This is the principle by which electric generators work. The faster you spin a magnet, the stronger the electric current you generate will be. The corollary is also true — the higher the voltage of your initial current, the stronger the magnetic field you will generate around the wire.

  Credit card swipes are no different. When you swipe your credit card, you generate an electrical pulse in the read head. The faster you swipe the card, the stronger the electrical charge generated by each magnetized particle will be. You are encouraged to swipe quickly so that the read head can receive the strongest possible signal. The stronger the signal, the better chance the read head has of interpreting the data correctly.

  Eventually, you may see these signs disappear. Larry Meyers, director of engineering for MagTek Inc., a Carson, California, company that manufactures card readers and specializes in “magnetic stripe card solutions,” wrote Imponderables warning that these Remove Card Quickly signs might go the way of the dodo:

  From a practical standpoint, most card readers today use electronic designs that feature AGC (automatic gain control). This allows the electronics in the card reader to automatically compensate for low electrical signals which occur during slow swipes. Thus, to a large extent, the need to “swipe quickly” has been eliminated.

  But there’s another reason why swiping quickly might still be a good policy for the prudent customer: Fast swipes are smooth swipes! A smooth swipe provides fewer read errors, primarily because card readers work best when the card is withdrawn in a continuous motion. Stewart Montgomery, a customer-service representative at MagTek, notes that the Swipe Quickly sign

  is to prevent the cautious person from moving the card at an extremely slow and uncertain rate. Moderate speed is best for the magnetic sensors used for credit-card magnetic-stripe reading. The typical acceptable speed is usually specified in a range between three and 50 inches per second.

  That’s quite a range. We don’t think we’ve ever been so enthusiastic about paying, even by plastic, that we’ve managed the fifty - inches - per - second swipe.

  Montgomery’s point was echoed by Dave Lewis, a technical-support representative from Corby Industries, who argued that “fast” really means “steady”:

  Magnetic-stripe cards hold a string of information usually defined on track two of the card. This track two is in a format set by the American Banking Association. There are generally as many as sixteen distinct characters within this track, all numeric or numeric equivalent. This is why there are sixteen digits on your credit card or ATM card.

  Since this numeric encoding is in a string, it is more likely to be read correctly if pulled through the reading device in a uniform fashion. Swiping the card too slowly may cause space between the character information, causing a misread of the card. It’s like pulling a train with an engine. If all the cars stay connected to the engine it is much easier to reach the destination quickly. A break between the cards will create space and slow down the train, especially if the cars need to be reconnected.

  This is why people are told to swipe their card “quickly.” It really means “steadily.” People understand the term “quickly” easier. This is why the money machines ask for a quick swipe.

  Speaking of swiping quickly, when we use our ATMs, why do banks remove money from our account right away? When we deposit our meager paychecks, it seems to take weeks for our money to be credited to our account. As long as the banks set the rules, perhaps this isn’t an Imponderable after all.

  Submitted by Amber Burns of Salem, Oregon.

  Some Credit Card Reading Machines Ask You to Dip the Card and Pull It Out Rather Than Swipe. Does the Reader Pick Up the Data on the Way In or the Way Out?

  The machines that ask you to dip your credit card are, appropriately enough, called “DIP readers.” Once again, the industry has to adjust for those users who just aren’t smooth enough. Card-reader manufacturer MagTek’s director of engineering, Larry Meyers, explains:

  DIP readers normally have a mechanical or optical sensor at the rear of the reader, which detects when the card is fully inserted. Using this sensor as a reference, the DIP card readers are then “programmed” to wait until the card is fully inserted, and then will only read card data as the card is being withdrawn from the reader.

  This approach is taken because users often have an awkward time inserting the card into the reader. If the card is “jerkily” inserted into the reader, it is not an ideal condition to try and read card data. However, once the card is fully inserted, it is very easy for the user to withdraw the card in a smooth, controlled motion that optimizes card reading conditions.

  Submitted by Ernie Capobianco of Dallas, Texas.

  Why Are Flour Tortillas Larger Than Corn Tortillas?

  Which came first: the big flour tortilla or the big burrito? If corn tortillas were as large as flour ones, and were stuffed accordingly, we’d be ordering fewer tacos at a pop, wouldn’t we?

  Although there are no strict standards, most corn tortillas are about six inches in diameter (although 5½ inches is another popular size for prepackaged corn tortillas) and rarely exceed seven inches. Flour tortillas can be found that are as big as a medium pizza (twelve inches), although smaller ones also are available that are no bigger than their corn counterparts.

  Corn tortillas are thought to date back several millennia before Christ and became the staple of the Aztecs’ diet by the sixteenth centur
y. When the Spanish conquerors came to the highlands of Mexico, they found the native women pounding corn to make bread; the Spanish dubbed the bread tortilla, or “small cake.” The Spanish later introduced wheat to Latin America, and flour tortillas, created only in the past few centuries, were the result.

  Traditionally, the first step in preparing corn tortillas was soaking corn in a lime solution that eliminates the husks. The corn kernels are then ground with a stone into masa, and the dough is then combined with water and mixed by hand into a golf-ball-sized sphere. The masa is then rubbed between the cook’s hands and patted into a flat pancake of approximately six inches. The six-inch dimension wasn’t a function of any particular standard, rather it was as big a dough as could be molded easily by hand. If it were any bigger, the tortilla would flop over the outsides of the baker’s hands and fall apart. The eponymous Maria Vega of Maria’s Tortillas in Los Angeles, California, elaborates:

  The dough just doesn’t hold its consistency in larger sizes. If you try to slowly and carefully pat out a larger corn tortilla, even on a table or other flat surface, it tends to fall apart and develop cracks. You can sometimes do it if you’re very careful and take your time, but it’s difficult.