Why Do Pirates Love Parrots? (18 page)
Read Why Do Pirates Love Parrots? Online
Authors: David Feldman
Both boxes are placed in the most “survivable” part of the aircraft, usually in the tail section. Each of these recorders are equipped with an underwater locator beacon, which sends an ultrasonic pulse so that receivers can locate them in the water, and are built to withstand water pressure as deep as 20,000 feet below sea level. To further assist their retrieval in usually difficult circumstances, the boxes are not only painted a bright color, but are covered with fluorescent reflective tape.
We’ve heard many different theories about why the recorders were called “black boxes” in the first place. As black boxes are sought after crashes, one theory is that “black” refers to the death surrounding their use. Boeing’s Ken Giesbers remembers the term “black box” from engineering school to describe a device having unknown contents:
When testing a black box unit, you could apply inputs and measure outputs, but you did not know what was going on inside the unit. Considering how rugged and well-sealed these devices are, I think they qualify as “black boxes” to many people.
Were black boxes actually ever painted black? So far, we haven’t been able to verify that they were.
We frequently receive comments from readers arguing that if we can answer one of the questions in our books, then the conundrum can’t be called “imponderable.” If we answer a question, haven’t we pondered it? Our
Merriam-Webster’s Collegiate Dictionary
defines “ponderable” as “significant enough to be worth considering.” Surely, no one could think that the consideration of why you never see baby pigeons could possibly be insignificant. If there are such folks, we hope they seek counseling for their wounded souls.
But to us, “imponderable” means more than just “not ponderable.” It refers to the state of anxiety we feel when a question burns to be answered but we fear it never will.
Some dictionaries also define “imponderable” as a question that can’t be answered by numbers or exact measurement. That’s a description we can buy. We promise that the answer to an Imponderable will never be “15” or “True.” The mysteries of everyday life usually defy easy answers, and if a question is interesting enough, who cares about its practical application? It’s worth pondering.
Fouled
Anchor as Their Symbol?
A
fouled anchor is one that has its line or chain wrapped around it. No sailor worth his salt would show pride in mucking up an anchor in this way, yet the graphic depiction of the fouled anchor has graced the uniforms of the U.K., U.S., and Canadian navies for centuries.
The fouled anchor has an illustrious lineage. It was the official seal of Lord High Admiral Charles Lord Howard of Effingham, who oversaw the English victory over the Spanish Armada in 1588. Ever since, the fouled anchor remains the official seal of whoever occupies the seat of the Lord High Admiral of Great Britain.
We can find no answer to this Imponderable more convincing than the Naval Historical Center’s. If any group would seek to justify the inappropriate imagery, it should be the Navy. And yet there is no better response than the Navy’s: “It looks pretty.”
It seems strange that the navies of the world should use as an insignia the abomination of all good sailors. Somewhere back in the early days, a draftsman with more artistic ability than technical knowledge produced the well-known design which shows an anchor with its cable hopelessly fouled around the shank and arms. How such a design could win the approval of the Admiralty Board is beyond comprehension, but the fact remains that the sight of the fouled anchor has become an international emblem.
Perhaps it could be argued that the fouled anchor is like the choking sign in a restaurant—a cautionary symbol. But we doubt it. Navy personnel have had a long tradition of getting a tattoo after they have completed their tour. The most popular design? A fouled anchor.
Submitted by Michael, via the Internet.
B
efore we get deluged with mail—we know! Yes, you can find circuit boards in almost as many colors as Crayola has crayons, including red, gold, pink, yellow, brown, and black. Tracy Elbert, product manager for PCBexpress, wrote
Imponderables
that her company used to manufacture rainbow-colored boards, with “a drizzle of all the colors spiraled around randomly.” But dark green boards have become the default color. Why?
On one level, the answer is easy. The green color on most circuit boards, not just on computers, but on everything from pinball machines to television sets, comes from the “solder mask.” The solder mask, found on both the top and bottom of a PCB (printed circuit board) can be applied as a dry film, printed in a silk screen–like process, or now most commonly, applied in a liquid form.
The purpose of the solder mask is not to look pretty but to cover and insulate the parts of the circuit that don’t require soldering. All kinds of bad stuff can result if solder strays from its intended destination—shorts being the most serious consequence, as Mike Lopez, of PCB manufacturer Prototron Circuits, explains:
The green color actually is an epoxy-based material that acts as a solder resist. When components are loaded onto a board, the solder mask resists the solder from jumping over to another hole or pad location, which would cause a short in the circuit. Now the assembly process becomes easier knowing that if you load all the components from one side and run it along with a conveyor belt and flowing solder beneath it, all of the leads that come through the holes will wick up perfectly and keep the solder to the metal only and not form a big solder mess.
We also know that there is a certain amount of inertia with the colors of things. If circuit boards have always been green, then why rock the boat? The manufacturers don’t have much incentive to change, unless customers seek new colors. But Elbert points out that there is cleanup and waste involved in her plant switching back and forth between different colors—the dark green default is fine with her.
We know that the oldest circuit boards were not green. Bob Dietzel, who spent twenty-nine years at Bell Labs doing integrated circuit research and development, told
Imponderables
that before commercially applied coatings were available, Bell Labs made its own boards, which were translucent white.
These boards were soldered by hand in those days so no mask was needed. We had a shop full of “wiremen” who placed the components on the boards and soldered them.
The earliest circuit boards were masked by hand with a tar-like substance and etched by hand in an acid solution. This soon was replaced with masks made with rub-on masking and etched with ferric chloride solution.
Tom Wagner, an audiovisual technician and Web designer from Malaspina, British Columbia wrote about the rainbow of colors found on early boards:
The color of the board shows the composition of it, hence the use of it.
Original and older boards were Bakelite composition, and were brown.
Phenolic [boards were]…tan.
Most “non filled” fiberglass boards used in computers are green.
Filled fiberglass is blue.
Teflon is white.
But why was the solder mask green in the first place? One theory, advanced in 2000 on IPC’s TechNet E-Mail Forum by David Albin, of Coates Circuit Products, is that the solder mask manufacturers used the materials at hand, in this case a
copper phthalocyanine pigment, which at the time of the first boards, was the only heat-stable organic colour [available].
Others “blame” Uncle Sam for our dark green solder mask. Mike Lopez writes:
I’ve heard that PCBs were starting to develop colors back in World War II days and green was the color of choice for the military.
Another poster on the TechNet board sides with the armed forces theory:
The green color of solder mask was chosen after extensive testing by the U.S. military at the National Materials and Procurement Center in Cedar Bluffs, Virginia in late 1954. According to Colonel Robert Bright, Public Liaison Officer, the particular shade of green was found to provide the maximum contrast to the white silkscreen ink under all tested adverse situations while still allowing a clear view of the underlying circuitry. Every other color tested failed to provide the required contrast under conditions of low/high illumination levels and various colored light sources. The quantity of printed circuit boards purchased by the Defense Department established the “de facto” standard which most vendors began to follow. Usage of other colors is permitted for prototype and or pre-release boards.
Regardless of whether or not the military mandated dark green, some argue that green is the color easiest on the eye, especially for long periods, while providing sufficient contrast for board assemblers and inspectors who were supervising their work. Even the manufacturers of PCBs have a selfish reason to prefer green, as Tracy Elbert explains:
The liquid solder mask we use is like an epoxy, which needs to be cured to harden. Green is the easiest color for the UV light to accept, making the process easy for us.
But some manufacturers of electronics equipment color-code their PCBs when developing or testing new circuits, in order to distinguish between different kinds of boards, or to test the efficacy of one over the other. Paul Morgan, of circuit board manufacturer K&F Electronics, told
Imponderables
that solder masks are available in all the primary colors,
though mixing any color is possible. Black and white are also available, making gray yet another choice. Some companies use the different colors for color coding, such as red for experimental research and development and green for production. Black is typically used to block light for applications such as automobile dash board displays.
Most big PCB manufacturers offer designer colors, sometimes at premium prices. But it will take more than a passing fad to make anything other than dark green the “new black” in the solder mask biz.
Submitted by Scott Bossak of Brooklyn, New York.
D
ogs can definitely be trained not to shake off water near people, but given their druthers, they’ll do it every time. Fred Lanting, a dog judge, breeder, and author, notes that if dogs don’t see anyone, or are wild or feral, they don’t wait to shake off. But Lanting observes that when a domestic dog has his owner around, Fido wants to share the moment:
Why do dogs head for you and
then
shake the water off? Perhaps they think your name is Everest. Because, like Everest, you are there. If no one were near, the dog would shake as soon as convenient. But dogs are social animals with a very strong emotional attachment to and dependency upon man, and their psychological desire to be near you is momentarily stronger than their physiological need to shake off the water.
Dog trainer and author Suzanne Clothier concurs:
In my own pack of six to eight dogs, I have noticed that when play is not involved (i.e., my dogs are swimming at free will in the pool or stream), they shake almost immediately upon exiting the water. When I or another person is involved, as we often are throwing bumpers or balls into the water, the dogs exit the water but delay shaking until within three to six feet from us.
Is there the tiniest chance that dogs might be exhibiting a little catlike streak? Robert Habel, professor emeritus of Cornell University’s College of Veterinary Medicine ponders:
Possibly they seek vengeance for being sent into the water after a stupid stick. Possibly they want immediate commendation for going into the water. Or for coming out.
Nah. Dogs don’t have enough guile to splash us passive-aggressively. We side with the dog trainer JP Yousha, of El Paso Texas, who suspects that dogs shake in front of their masters
to share their joy. A wet dog, at least one who enjoys the water, is in no hurry to shake and naturally returns to the one he adores to show his delight.
Submitted by Glenn Jones of Wantagh, New York.
