Part 5 (1/2)

Merry Wooten, of the Astronomical League, informs us that most early telescopes didn't yield upside-down images. Galileo's original spygla.s.s used a negative lens as an eyepiece, just as cheap field gla.s.ses made with plastic lenses do now. So why do unsophisticated binoculars yield the ”proper” image and expensive astronomical telescopes render an ”incorrect” one?

Astronomy editor Jeff Kanipe explains: The curved light-gathering lens of a telescope bends, or refracts, the light to focus so that light rays that pa.s.s through the top of the lens are bent toward the bottom and rays that pa.s.s through the bottom of the lens are bent toward the top. The image thus forms upside down and reversed at the focal point, where an eyepiece enlarges the inverted and reversed image.

Alan MacRobert, of Sky & Telescope magazine, adds that some telescopes turn the image upside down, and others also mirror-reverse it: ”An upside-down 'correct' image can be viewed correctly just by inverting your head. But a mirror image does not become correct no matter how you may twist and turn to look at it.”

O.K. Fine. We could understand why astronomers live with inverted and upside-down images if they had to, but they don't. Terrestrial telescopes do rearrange their image. Merry Wooten says that terrestrial telescopes can correct their image by using porro prisms, roof prisms, or most frequently, an erector lens a.s.sembly, which is placed in front of the eyepiece to create an erect image.

Why don't astronomical telescopes use erector lenses? For the answer, we return to Jeff Kanipe: Most astronomical objects are very faint, which is why telescopes with larger apertures are constantly being proposed: Large lenses and mirrors gather more light than small ones. Astronomers need every sc.r.a.p of light they can get, and it is for this reason that the image orientation of astronomical telescopes are not corrected. Each gla.s.s surface the light ray encounters reflects or absorbs about four percent of the total incoming light. Thus if the light ray encounters four gla.s.s components, about sixteen percent of the light is lost. This is a significant amount when you're talking about gathering the precious photons of objects that are thousands of times fainter than the human eye can detect. Introducing an erector into the optical system, though it would terrestrially orient the image, would waste light. We can afford to be wasteful when looking at bright objects on the earth but not at distant, faint galaxies in the universe.

And even if the lost light and added expense of erector prisms weren't a factor, every astronomer we contacted was quick to mention an important point: There IS no up or down in outer s.p.a.ce.

Submitted by William Debuvitz of Bernardsville, New Jersey.

Why Are the Rolls or Bread Served on Airlines Almost Always Cold While Everything Else on the Tray Is Served at the Appropriate Temperature?

We won't even comment on the taste of airline food (this is a family book). But if McDonald's can separate the cold from the hot on a McDLT sandwich, why can't the airlines get their rolls within about 50 degrees of the right temperature?

The answer lies in how airline meals are prepared aloft. The salad, bread, and dessert are placed on trays that are usually refrigerated or packed in ice. Entrees are loaded onto separate baking sheets. When it is time to start the meal service, the flight attendant who prepares the meals simply sticks the trays of entrees into ovens (not, by the way, microwaves).

The rolls are cold because they have been sitting all along with the salad and cake. Most airlines offer customers a choice of entrees. The flight attendant who is serving the meal simply selects the entree from the sheets they were cooked in and places it alongside the rest of the meal. Except for the entree choice, every flier's tray will look identical. Note that although most airlines vary the vegetable according to the entree, the vegetable is always cooked on the same plate as the main course because the entree plate will be the only heated element on the tray.

If the bread and salad taste cold, why doesn't the dessert? Airlines, almost without exception, serve cake for dessert. Michael Marchant, vice president of Ogden Allied Aviation Services and the president of the Inflight Food Service a.s.sociation, told Imponderables that the softness of cake fools us into thinking it is being served at room temperature. The gustatory illusion is maintained because in contrast to the roll's hard crust, which locks in the coldness, the soft frosting of a cake dissipates the cold.

The folks in first cla.s.s, meanwhile, are munching warm rolls, which have been heated. Certainly it is worth an extra five hundred dollars or so to get heated rolls, isn't it?

Why Do Chickens and Turkeys, Unlike Other Fowl, Have White Meat and Dark Meat?

Other birds that we eat, such as quail, duck, or pigeon, have all dark meat. Chickens and turkeys are among a small group of birds with white flesh on the b.r.e.a.s.t.s and wings.

Birds have two types of muscle fibers: red and white. Red muscle fibers contain more myoglobin, a muscle protein with a red pigment. Muscles with a high amount of myoglobin are capable of much longer periods of work and stress than white fibers. Thus, you can guess which birds are likely to have light fibers by studying their feeding and migration patterns.

Most birds have to fly long distances to migrate or to find food, and they need the endurance that myoglobin provides. All birds that appear to have all white flesh actually have some red fibers, and with one exception, all birds that appear to be all dark have white fibers. But the hummingbird, which rarely stops flying, has pectoral muscles consisting entirely of red fibers because the pectoral muscles enable the wings to flap continuously.

The domestic chicken or turkey, on the other hand, lives the life of Riley. Even in their native habitat, according to Dr. Phil Hudspeth, vice president of Quality and Research at Holly Farms, chickens are ground feeders and fly only when nesting. Ordinarily, chickens move around by walking or running, which is why only their legs and thighs are dark. They fly so little that their wings and b.r.e.a.s.t.s don't need myoglobin. In fact, the lack of myoglobin in the wing and breast are an anatomical advantage. Janet Hinshaw, of the Wilson Ornithological Society, explains why chicken and turkey musculature is perfectly appropriate: They spend most of their time walking. When danger threatens they fly in a burst of speed for a short distance and then land. Thus they need flight muscles which deliver a lot of power quickly but for a short time.

Next time you fork up an extra fifty cents for that order of all-white meat chicken, remember that you are likely paying to eat a bird that racked up fewer trips in the air than you have in an airplane.

Submitted by Margaret Sloane of Chapel Hill, North Carolina. Thanks also to Sara Sickle of Perryopolis, Pennsylvania; and Annalisa Weaver of Davis, California.

Why Haven't Vending Machines Ever Accepted Pennies?

In the second half of the twentieth century, when a child is more likely to think that penny candy is the name of a cartoon character rather than the actual price of a confection, it is hard to believe that in the early days of vending machines the industry would have loved to be able to accept pennies. When a candy bar cost five cents, vendors undoubtedly lost many sales when frustrated kids could produce five pennies but not one nickel. Now, when a candy bar might cost half a dollar, payment in fifty pennies might clog a receptacle. But why didn't vending machines ever accept pennies? We spoke to Walter Reed, of the National Automatic Merchandising a.s.sociation, who told us about the fascinating history of this Imponderable.

The vending machine industry has always been plagued by enterprising criminals who inserted slugs or relatively worthless foreign coins into machines in the time-honored tradition of trying to get something for nothing. In the 1930s, a slug rejector was invented that could differentiate U.S. coinage from Mexican centavos of the same size. The slug rejector worked by determining the metallic content of the coin. Although the slug rejector could easily differentiate between silver or nickel and a slug, it couldn't tell the difference between a worthless token and the copper in a penny. For this reason, vendors hesitated to accept pennies in the machines.

The slug rejectors of today are much more sophisticated, measuring the serration of the coin, its circ.u.mference, its thickness, and the presence of any holes. Whereas the 1930s slug rejector was electromagnetic, current rejectors perform tests electronically.

The vending machine industry was instrumental in pus.h.i.+ng for the clad-metal coins that were introduced in 1965. Since that year our quarter, for example, which used to be made of silver, now has a center layer of copper surrounded by an outer layer of copper and nickel. The copper-nickel combination reacts to the electronic sensors in vending machine rejectors much like silver. The government also loves the clad coins because the const.i.tuent metals are so much cheaper to buy.

Except in gumball machines, the vending machine industry has never accepted pennies, although they once gave pennies away to consumers. In the late 1950s, a cigarette tax was imposed that drove the retail price of cigarettes a few cents above its long-held thirty-five-cent price. Stores simply charged thirty-seven cents, but vending machines couldn't, for they were not equipped to return pennies.

Vendors had to decide whether to keep charging thirty-five cents and absorb the loss of the two cents on every pack, or charge forty cents and risk loss of sales when grocery stores could undercut them by 10%. So they compromised. Vending machines charged forty cents a pack, but pennies were placed in the pack to restore equity to the consumer.

Submitted by Fred T. Beeman of Wailuku, Hawaii.

Now that Most Products Sold in Vending Machines Sell for Fifty Cents or More, Why Don't Most Vending Machines Accept Half Dollars or Dollar Bills?

The problem with the half dollar is that the public does not carry it in its pocket. Half dollars are too bulky and heavy. Allowing half dollars would necessitate increasing the size of coin slots in the machines.

The American public loves quarters. Unfortunately, studies have shown that people resist putting in more than two coins in vending machines. And two quarters aren't enough to buy even a soft drink anymore.

So isn't the dollar bill acceptor the panacea? The technology exists to accept dollar bills in vending machines, but the same ha.s.sles that plague the consumer using dollar-bill changers are also a nightmare for the vendor. Bills must be placed in the proper position to be accepted. Worn or slightly torn bills are rejected routinely even though they are perfectly legal tender. And worst of all, dollar bills can't be counted easily by machine. The labor involved in counting paper money is not insignificant.

The vending machine industry l.u.s.ts after the resuscitation of the silver dollar. Frustrated by the unpopularity of the Susan B. Anthony dollar, trade groups are now pus.h.i.+ng for a new gold-colored dollar with a portrait of Christopher Columbus on the obverse. The Treasury supports the proposal, for although coins are more expensive to manufacture than bills, they last much longer in circulation. Walter Reed points out that no other industrialized nation has an equivalent of a one dollar bill in paper currency anymore. The Canadians were the last to fall, with the Looney dollar, the same size as the ill-fated Susan B. Anthony, replacing their dollar bill.