Come along for a walk on science's wild side, where beaches go bump in the night, sand dunes howl, church bells mysteriously refuse to ring and thunder rumbles out of a clear blue sky.
The tales you are about to read are true - drawn from the annals of science.The walls have ears
In the ancient dungeons of Syracuse, prisoners' conversations were overheard via a concealed opening in the floor of their cells. The opening was connected to a tube that led through the floor and walls to the waiting ears of the tyrant.
This diabolical trick was accomplished by shaping the room acoustically to reflect sounds toward this hidden "Ear of Dionysius," an eavesdropping device invented long before the advent of electricity.
More recently, the dome covering the old Hall of Representatives in the Capitol building in Washington, D.C., acted like a sound-focusing dish that could reflect even a whisper from one side of the chamber to the other, rendering it clearly audible to the opposing party.
Even more embarrassing revelations occurred long ago in the Cathedral of Girgenti in Sicily with its unusual elliptical shape (like an elongated circle, with a point of focus near each end). It is a curious quality of ellipses that sounds emanating at one of the focus points will bounce off the walls and be refocused audibly at the other point, even if it is located hundreds of feet away. When the church's confessional was inadvertently placed at one of these two points, even a whispered admission could be overheard easily near the other end of the long oval room.
One day when a delighted discoverer of the cathedral's eavesdropping properties brought along friends to share in a few laughs at unsuspecting penitents, his own wife entered the confessional and told tales that were anything but amusing to the startled husband.
Out of the clear blue sky
Throughout history, tales have been told of mysterious rumblings and cracklings coming down out of the clear blue sky. Called brontides, mistpoeffers or Barisal guns, these eerie sounds are from rare. Near the Bay of Bengal, they're so common that the inhabitants ascribe them to the gods. Elsewhere, they're dismissed as sonic booms.
Mostly likely, they're what scientists call anomalous propagation - sounds of anything from distant thunder to explosions that travel up into the warm stratosphere and then are bent back down toward the earth by high-altitude temperate conditions that act lie a camera lens.
Though thunder normally can't be heard much beyond 15 miles, by bouncing back and forth between the earth and a warmer upper atmosphere, it can reach more distant points and may in places appear to come down out ot the clear blue sky.
A light show of the mind
When prisoners are confined in dark cells for long periods, they may begin to see brilliant lights emanating from their inner eyes called phosphenes (also known as "prisoner's cinema").
Truck drivers staring for many hours at snow-covered roads may see this same sort of inner display.
In Benjamin Franklin's day, phosphene parties were popular - the usually pragmatic Franklin did this once himself. At these parties groups of people would join hands in a circle and receive a high-voltage shock from an electrostatic generator. Somehow, the completing or breaking of this people-circuit created an electrical stimulus to their brains that unleashed colorful phosphene light shows.
But such extreme measures are not necessary to experience this strange phenomenon: one can generate colorful phosphene images almost at will by rubbing closed eyes or pressing against the lids with fingertips.
Phosphenes may even one day have clinical significance. Researchers have found that some blind people experience phosphene displays, suggesting the possibility that they may be harnessed to create artificial vision. One approach might be to hook up a miniature TV camera to a pair of computerized eyeglasses that are in turn wired into the occipital region of the wearer's brain. Phosphene images could then be stimulated to parallel the shapes and locations of objects in the external world.
Howling sands and booming beaches
On some of the world's beaches, the sands are said to whistle when walked on. In certain deserts, sand dunes are reported to boom out noises so loud they make normal conversation impossible.
Though a full explanation for these phenomena is lacking, they seem to involve rapid oscillations of spherical sand grains when placed under a shearing stress - in the first case due to the walker's weight, and in the second due probably to wind-blown avalanches that somehow trigger sand vibrations on the leeward, or downwind, side of the dune.
Things that glow in the dark
Catching fireflies on a summer night can be one of the delights of childhood. Yet though the darting lights appear as tiny evanescent sparks, they are actually a form of "cold" light resulting from "chemiluminescence." Unlike incandescent bulbs, candle fire or red-hot pokers, firefly light does not result from high temperatures and rapid thermal agitation of molecules, but is set off by a series of highly efficient chemical reactions that emit visible photons without losing any energy to heat.
Many other organisms can also produce light. The Brazilian railroad worm, for instance, has a red light on its head and green lights down its side. Another type of luminescent organism, the dinoflagellates, will "set the sea on fire" when disturbed during the day.
One type of crustacean, called Cypridiona hilgendorfii, when dried can be made to glow by moistening. Such a light source was used by Japanese soldiers during World War II when using a stronger light was too dangerous. Spitting on a bit of dried crustacean would give off just enough light to read a map.
The opera singer and the broken bridge
Many a veteran TV watcher has seen the opera singer shatter the champagne glass with a piercing high note.
The singer is able to shatter the glass because all objects have certain natural frequencies at which they will vibrate (just like piano strings). If the singer's pitch matches the natural frequency of the glass, the sound energy may build until the object shatters.
A similar phenomenon, with tragic results, occurred in 1831 when troops marched in step across a suspension bridge in Manchester, England, causing it to vibrate and eventually collapse. Ever since, marching troops have been ordered to break stride when crossing such bridges.
The Archimedes death ray
The great Greek scientist Archimedes saved the ancient city of Syracuse from Roman attack by developing the world's first death ray.
As the Roman ships approached, legions of Greek troops were directed to stand along the shore and hold up huge mirrors. As the rays of the sun bounced off these myriad reflecting surfaces, they were aimed at and concentrated on a single target ship (not unlike a child using a magnifying glass to burn a leaf). One by one, the boats of the would-be conquerors burst into flames and sank.
Is this dramatic tale really true? Is it scientifically possible? Some years ago, a Greek engineer duplicated the Archimedes death ray. He had soldiers use 70 5-foot-by-3-foot flat mirrors to aim reflected sunlight at a test rowboat 160 feet offshore. Once the soldiers mastered maneuvering the huge mirrors, they were able to set the boat ablaze within seconds.
The bell that wouldn't ring
When the Cathedral of Cologne's belfry was completed, workmen discovered that the bell inside the belfry wouldn't ring.
Wise men came from near and far to study the matter but left scratching their heads. All parts seemed in perfect working order: bell, rope and clapper.
Yet no sound could be heard.
Finally, one of the men who engineered construction of the belfry devised a plan. He proposed that the bell's clapper be lengthened, reasoning that since a long, heavy pendulum (the bell) swings at a certain rate due to the distribution of its weight along its length, and a shorter pendulum (the clapper) must also do likewise, perhaps these two rates just happened accidentally to coincide for this particular bell. Hence no ringing.
Straightway the bell's clapper was lengthened, and straightway the air about the cathedral was filled with the jubilant ringing of the church bell.
Just a little gas
When the first tunnel under London's Thames River was completed in 1842 by joining the two underwater shafts, an on-site celebration ensued. Champagne was uncorked and imbibed in the pressurized chamber at the tunnel's bottom.
Finding the drink a bit lifeless and flat, London's civic leaders decided to return above ground to fetch a better bottle, only to find the previously flat spirits beginning to "pop in their stomachs and all but froth from their ears." According to the "Journal of Chemical Education," one dignitary had to be "rushed back into the depths to undergo champagne recompression."
Apparently, the greater-than-atmospheric pressure in the tunnel had suppressed the normal, gradual release of the champagne's bubbles, causing the gaseous buildup in the celebrants' stomachs.
A little hemlock in the ear
What do high-speed cars, ocean surfs, airplanes, thunderstorms, tornadoes and earthquakes have in common?
All of these potentially irritating noisemakers may also emit infrasound - sound at sub-audible frequencies - that can cause nausea, dizziness and motion sickness. In very rare cases the infrasound can become so strong that it vibrates the chest or other parts of the body, causing internal bleeding and eventual death.
Some scientists speculate that infrasound sensations are what allow some people and most animals to "sense" an impending earthquake.
In a world where machines wear out, musical instruments go out of tune, and clocks run down, how do our bodies stay young for as long as they do?
By borrowing energy from food and sunlight, we manage to beat the odds and swim against the cosmic currents of disorder and disorganization, at least for a joyous while.
Noted science writer Lewis Thomas described it this way in his book, "The Lives of a Cell":
"We make our living by catching electrons at the moment of their excitement by solar photons, swiping the energy released at the instant of each jump and storing it up in intricate loops for ourselves. . . . To have sustained the effort successfully for the several billion years of life's existence, without drifting back into randomness, was nearly a mathematical impossibility."
From this perspective, how can things not seem strange at times?
- Bill Sones is a free-lance writer. Jearl Walker, Ph.D, is a professor of physics at Cleveland State University and author of "The Flying Circus of Physics," John Wiley and Sons Inc., from which this piece is adapted. Professor Walker writes a monthly column - "The Amateur Scientist" for Scientific American.