All road and tunnel tests seem to confirm that particle debris found along roadsides accounted for at least 50 percent of the total missing tire tread, and possibly much more. One study indicated that 2
percent of all roadside dustfall consisted of worn tread material.
Another study, in Detroit, found that of the total particulate loading in the air, only 1 percent was tread dust. Even in tunnel tests, tire tread comprised only 1 to 4 percent of the total airborne particulate matter generated—a percentage far less than that of the exhaust emissions of gasoline-and diesel-powered vehicles.
All the tests concur, then, that the vast majority of worn tread in particle form falls on the ground instead of staying in the air.
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What happens to the rest of the worn tread? Much of it is dissolved through oxidation and devulcanization (a chemical reaction that reverses the process used to harden rubber). One estimate speculated that devulcanization accounted for 30 percent of the disappearing SBR. Wind, water runoff, oxygen, and microbial attack all act to help degrade tread particulates, which degenerate faster than the tread rubber on tires in any case.
In fact, nobody could get very excited about the possible environmental dangers of worn tire tread. If the tread particulate were light enough to remain airborne, it could cause some harm, but the 95
percent plus that settles into the ground near the roadway poses no health hazard. K. L. Campbell, of Firestone Tire & Rubber Company, points out that “Tire tread rubber is essentially an inert material so it doesn’t contribute to acid rain or soil pollution.” And because worn tire-tread particles on the ground are in too small a form even to see with the naked eye, we aren’t even aware that they are there.
Which proves again that what you can’t see can’t hurt you.
Submitted by Larry Orbin, of Florissant, Missouri. Thanks also to: Brad Miles, of Victoria, British Columbia; G. William Foster, Jr., of Tulsa, Oklahoma; and Art Lombard, of Oakland, California.
Why Do Whips Make a Cracking Sound When Snapped?
Whips can attain a speed of more than seven hundred miles per hour when snapped, breaking the sound barrier. What you are hearing is a mini sonic boom.
74 / DAVID FELDMAN
How Did Xmas Come to Stand for Christmas?
The use of the colloquial “Xmas” has often been singled out as an example of how the holiday has been commercialized and robbed of its religious content. The X in Xmas is actually the descendant of the Greek equivalent of Ch, as in “Christos,” which means “Christ.”
The letter X has stood for Christ (look up X in any dictionary) since at least A.D. 1100, and the term “Xmas” was first cited in 1551.
Word expert Eric Partridge points out that the scholarly abbreviation for “Christianity” is “Xianity.”
So many people dislike “Xmas” for its supposed crassness that its use is now virtually confined to commercial literature and banners.
The New York Times Manual of Style and Usage, for example, offers this simple recommendation for when “Xmas” is acceptable: “Never use.”
Submitted by Bobby Dalton, of Maryland Heights, Missouri.
Thanks also to: Andrew Neiman, of Dallas, Texas.
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Do Batteries Wear Out Faster If You Turn Up the Volume of a Radio?
Absolutely.
The battery applications manager of Eveready Battery Company, Inc., B.G. Merritt, told us about some research that proved the point conclusively:
We recently tested a major manufacturer dual cassette “boom box” powered by 6 “D” size cells. From lowest setting to highest setting on the volume control, the power necessary to drive the
“box” increased three times. This power increase directly translates into one third battery life at full volume when compared with zero volume. This power increase is necessary to drive the speakers.
By comparison, a personal stereo (portable type) cassette player current increased only 30% when adjusted from zero volume to full volume. Battery life would be decreased only 30%
for this device.
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Don French, a battery expert at Radio Shack, confirmed Eveready’s findings. He estimated that a shirt-pocket portable radio would use at least 200 percent more battery charge at the loudest volume setting than at the softest. French pointed out that even tiny radios have audio amplifiers that must be powered. A home stereo might require fifty watts and a shirt-pocket radio two hundred milliwatts, but the principle is the same—the more power required, the more juice required.
Submitted by Allen Kahn, of New York, New York.
Why Do Some Ranchers Hang Old Boots on Fenceposts?
It all started with an innocent call from a listener to Tannah Hirsch’s KMBZ talk show in Kansas City. The listener asked the Imponderable above, and we admitted that we didn’t have the slightest idea why some ranchers hang old boots on fenceposts. In fact, being urban folks, we had never seen this phenomenon at all. But it was an intriguing question, and we decided to investigate. The results will show you some of the trials and tribulations of tracking down answers to Imponderables.
A few weeks later, we received a letter from Rick Miller, who works at Kansas State University as an agricultural agent in Johnson County, Kansas. Rick had previously worked in southwestern Kansas, had seen boots hanging on fences, and had investigated. His conclusion was intriguing: “The boots are hung on the fence to discourage predators such as coyotes from entering fields where livestock are. The coyotes, with their keen sense of smell, pick up the human odor from the boots. Thinking humans are around, the coyotes won’t cross the fence.” Having
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read All the President’s Men and faithfully watched Lou Grant, we were determined to dig up a second source to corroborate Mr.
Miller’s story.
First we wrote to several ranchers’ organizations. All were familiar with the practice, but none mentioned the coyote angle, and only one had any theory at all—Rhoda G. Cook, executive secretary of the Montana Outfitters and Guides Association: “My late husband, who was a long-time packer and breaker of mules for the Forest Service said several times his boots were on the fence so everybody would know that a real cowboy lived there. I can vouch for the fact that they certainly smelled better out there than under the bed.”
Still missing the “smoking gun” that could definitively answer the Imponderable, we contacted all of the largest manufacturers of cowboy boots. Nobody could help us, but Frye sent us to Western Horseman magazine, where we spoke to writer Darrell Arnold and publisher Dick Spencer. Mr. Spencer didn’t put much stock in the coyote theory, but he remembered seeing long stretches of boots on fenceposts along Windless Hills, near Ogallala, Nebraska. He recommended that we contact someone in that area.
We found out that the newspaper of record in Ogallala was the Keith County News, published by Jack Pollack. Mr. Pollack was quite familiar with the stretches of boots on fenceposts, but didn’t know why they were there. He suggested we speak to some ranchers in the area and was kind enough to supply some phone numbers.
We contacted several ranchers, none of whom could say how the practice began. But one rancher, Waldo Haythorne, asked if we wanted to get in touch with the son of the man who started the tradition. We sure did!
And we found out that the pioneer in the practice of hanging boots from fenceposts was none other than Henry Swanson. According to his son, Virgil Swanson, after Henry put some worn boots on his fenceposts his neighbors followed his example, 78 / DAVID FELDMAN
until the path from the town of Arthur to the cemetery about a quarter-mile away was marked by boots at every ranch. Others copied the practice, and up in the hills above Arthur, there are longer stretches of boot-strewn fences (probably the ones Dick Spencer had spotted).
So, with great anticipation, we asked Virgil Swanson the question that had come to o
bsess us: WHY did your father hang the boots from the fencepost? He paused for a moment, and then replied,
“Gee. I really don’t know. I guess he just did it to do it.”
Dejected, we were back to first base. But quitters we are not. We called up our original correspondent, Rick Miller, to find out more about the coyote angle. Rick told us that coyotes have a keen sense of smell, and are uncommonly smart animals. Coyotes don’t like to mess around with people, and boots trapped the human scent better than anything else. Rick said that some ranchers in southwestern Kansas put boots on every single fencepost surrounding their fields, and it seemed to work for them. We were still a tad skeptical, because we couldn’t get anyone else, including a few vets we consulted, to confirm Rick Miller’s explanation. Rick suggested we speak to Bob Henderson, who works for the Kansas State Wildlife Department.
Bob Henderson, of course, did not confirm Rick’s theory. He felt that coyotes are too smart to be fooled more than once or twice by boots on fenceposts, and that coyotes are not as frightened by human odors as most people think. The problem with the boot-as-repellent theory is that coyotes, despite their excellent sense of smell, do not rely only on that sense. The coyote also uses its sight to determine whether it is safe to prey; once it becomes accustomed to seeing the same boots on the same fenceposts day after day, it won’t be timid about scaling the fence. In fact, Henderson said, coyotes are not afraid of human scent (human urine has even been used as an attract-ant to trap coyotes)—they are afraid of people.
Just as we were about ready to give up on this Imponderable WHY DO CLOCKS RUN CLOCKWISE? / 79
(or put it in the Frustrables section), we received a letter from Lynda Frank, of Omaha, Nebraska, posing the same Imponderable. We called her immediately. Although Lynda had no concrete theories, she assumed that the practice was simply a traditional one, without any practical purpose.
We then spoke to five or six experts in Animal Damage Control.
These are local or regional governmental agencies that attempt to rid areas of coyotes and other pests. None of them was familiar with the boot-repellent theory. One person referred us to Dr. Mike Fall, at the Denver Wildlife Research Center, a specialist in predator control. Like most good scientists, Dr. Fall was circumspect about speculating on a topic he had not researched himself, but he had grave doubts about whether boots on fenceposts would have any long-lasting effect on deterring coyotes from trespassing.
Dr. Fall emphasized that to discourage coyotes, you must chip away at one of their strengths—their adaptability. You must disrupt the patterns they encounter, for they can become accustomed to just about anything, including human odors. Scientists still don’t fully understand the impact of odors on coyotes. Scents have been developed that can consistently attract coyotes, but nothing yet can consistently repel them.
Fall predicted that boots on fenceposts would work over time only if the footwear were constantly rearranged, making the coyote insecure about whether humans were afoot. Experiments have been conducted using electric fences, guard dogs, and other animals, lights, and loud radios and tape recordings to deter coyotes, all with some, but limited success. The most promising approach, according to Dr. Fall, is a multistimulus deterrent, flashing lights with high-frequency sounds produced in random patterns, so that the coyotes are thrown off guard.
So—after consulting nearly thirty people, we still don’t have a definitive answer to this Imponderable. It has thoroughly humbled us. We would love to hear from readers who might have the answer.
Until then, we can only offer the three theories offered to us that make sense:
80 / DAVID FELDMAN
1. The boots scare away coyotes.
2. It is far wiser to stink up a fencepost than to stink up a house.
3. To paraphrase Virgil Swanson, “Some people just do things to do things.”
Submitted by Rick Miller, of Gardner, Kansas. Thanks also to: Lynda Frank, of Omaha, Nebraska.
Why Do Bananas, Unlike Other Fruits, Grow Upward?
If you knew about the tumultuous birth process of the banana, perhaps you would be more charitable the next time you encounter some bruised specimens at the supermarket.
The banana is actually a giant herb in the same biological family as lilies, orchids, and palms. It is the largest plant on earth without a woody stem—a banana stalk is 93 percent water—and is consequently extremely fragile. Although it can reach a full height of fifteen to thirty feet in one year, even moderate winds can blow down a plant.
The fruit stem or bunch originates at ground level. At this stage, the bunch consists of all of the fruit enclosed in leaf bracts. The individual fruit “fingers” (the technical name for a single banana) are pointed upward. As the bunch or bud is pushing its way through the mass of tightly packed leaf sheaths known as the pseudostem, the fruit fingers remain pointed upward until they emerge at the top of the plant.
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The bananas exert tremendous pressure on the pseudostem. Before the fruits expand, the leaves enclosing them roll around on themselves inside the trunk. After the fruit emerges from the leaves, the fingers point downward, but only because the bud surrounding them has changed direction.
Once the entire bunch of bananas is mature, fully emerged from its sheath, and pointing downward, the individual leaf bracts enclosing the hands (the female flower cluster) fall away, exposing the fruit. At this point, the individual flowers grow rapidly, filling out.
Their increased weight bends the main stalk so that the individual fruits on the hand start to turn upward in about seven to ten days.
Dr. Pedro Sole, of Chiquita Brands, points out that in the past,
“primitive bananas grew upwards, like the seeds of most grasses forming a spike.”
So is there a logical reason for the banana’s tortuous up-and-down birthing process now? Jack D. DeMent, of the Dole Fresh Fruit Company, sees the answer in the behavior of the traditional noncom-mercial banana plant:
A flower is found on the tip of each individual fruit. This flower is removed during [commercial] packing but is present during fruit development. As the hands turn up, the flower is better exposed to insects and nectar eating birds and bats. Their feeding would normally aid in fertilization of the fruit. Today’s commercial banana is sterile and rarely—almost never—produces a viable seed.
DeMent theorizes that the commercial banana’s tendency to grow upward is a holdover from its ancestors that needed to point upward for their very survival.
Presumably, natural selection will simplify the growth process of the banana over the next few hundred thousand years or so.
Submitted by Lynda J. Turner, of Hackettstown, New Jersey.
82 / DAVID FELDMAN
Why Is There a Black Dot in the Middle of Otherwise White Bird Droppings?
An important question, one that philosophers throughout the ages have pondered. Luckily, ornithologists know the answer.
That black dot is fecal matter. The white stuff is urine. The urine and fecal matter of birds collect together and are voided simultaneously out of the same orifice. Feces tend to sit directly in the middle of droppings because the urine, slightly sticky in consistency, clings to them.
Submitted by Ann Marie Byrne, of Queens, New York.
Do Toilet-Seat Covers Really Protect Us Against Anything?
We became suspicious about the efficacy of toilet-seat covers when we pondered, one day: why don’t they sell toilet-seat covers for home use? You see them only in public rest rooms. Perhaps the idea is not to protect you from disease, but from the thought of exposing your bare backside to the same surface area occupied by heaven knows who before you.
We were on the right track. Not only are venereal diseases not spread by toilet seats, but nothing else is, either. Although there was one report suggesting that the herpes virus may survive briefly in such an environment, the secretary of the American Society of Colon and Rectal Surgeons, Dr. J. Byron Ga
thright, Jr., echoed the senti-ments of other doctors we spoke to: “There is no scientific evidence of disease transmission from toilet seats.”
Submitted by Jean Hanamoto, of Morgan Hill, California.
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Why Do Sailors Wear Bell-Bottom Trousers?
Nobody knows for sure if there was one particular reason why this custom started, but three theories predominate: 1. The flared leg allows bell-bottoms to fit over boots easily.
Sailors traditionally sleep with their boots at the side of the bed, so that, in case of emergency, they don’t have to waste time trying to position their pants over their footwear. Once a sailor arrives on deck, having the trouser legs fully cover the top of the boot has practical advantages as well—it protects him from spray and rain entering his boots.
2. Bell-bottoms are easily rolled up. Because sailors often work with potentially harmful chemicals (scrubbing the deck with lye, for example), rolling up the cuffs prevents permanent damage to the pants. Also, if a sailor needs to wade ashore, bell-bottoms can easily be rolled up above the knee.
84 / DAVID FELDMAN
3. If a sailor is thrown overboard, bell-bottoms are also easier to remove than conventional trousers. And the loose fit of the bell-bottom also makes it easier to remove boots in the water.
Sailors in boot camp are taught another practical use for bell-bottom trousers. If the legs are tied at the ends, bell-bottoms can hold quite a lot of air; in a pinch, they can be used as flotation devices.
Why Doesn’t Sugar Spoil or Get Moldy?
Virtually all living organisms can digest sugar easily. So why isn’t sugar prone to the same infestation as flour or other kitchen staples?
Because sugar has an extremely low moisture content—usually about 0.02 percent—it dehydrates microorganisms that might cause mold. As John A. Kolberg, vice-president of operations at the Spreckels Division of Amstar Corporation, explains it, “Water molecules diffuse or migrate out of the microorganism at a faster rate than they diffuse into it. Thus, eventually the microorganism dies due to a lack of moisture within it.” Sugar’s low moisture level also impedes chemical changes that could cause spoilage.
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