Although seeing is believing, not seeing shouldn’t mean not believing. This is particularly true for radiation, since most forms cannot be seen directly. There is, however, one type of radiation that can be seen. This is light. Fortunately, light possesses many of the same properties as the invisible types of radiation. So we can overcome at least one barrier to understanding radiation by starting with the kind that we all can see, and then moving on from there to the invisible types that lurk ominously in the dark. We’ll begin our radiation journey by looking under the lamppost, where reality is revealed … and where jaguars dare not roam.
PART ONE
RADIATION 101: THE BASICS
CHAPTER 2
NOW YOU SEE IT: RADIATION REVEALED
A man should learn to detect and watch that gleam of light which flashes across his mind from within.
—Ralph Waldo Emerson
CHASING RAINBOWS
Radiation is simply energy on the move, be it through solid matter or free space. For the most part, it is invisible to us and can only be detected with instruments. But there is one type of radiation that can be seen with the naked eye. This visible radiation is called light.
Who isn’t fascinated by light? Whether as sunrises, fireworks, or lasers, light mesmerizes us because we can see it. Most of us have at least a rudimentary understanding of the physical principles of light because we have practical experience with it. We know that light casts shadows, bounces off mirrors, and comes in different colors. Other types of radiation have similar properties, but we don’t see them. They exist apart from our everyday experience, and thus seem mysterious—ever present but never seen. Yet, the physical properties of light have much in common with these other types of radiation. Hence, by examining what’s going on with light, we can actually get a glimpse of what is happening with its unseen cousins.
Light is just a tiny part of the world of radiation, but a very important part. We would be remiss if we neglected light; the story of radiation is strongly tied to its story. So as not to be remiss, let’s briefly review what we know about light.
Throughout prehistory, light came almost exclusively from the sun and fire. From these observations of light, primitive humans deduced that the sun was a massive ball of fire. This deduction, which was likely one of mankind’s first scientific conclusions, turned out to be absolutely correct.
Fire produces both heat and light, but warm things aren’t always bright (e.g., body heat), and bright things aren’t always warm (e.g., fireflies). These facts suggest that heat and light, though often found together and in some ways related, are fundamentally different phenomena that can be uncoupled and studied separately.
One of the things people noticed about light was that it could bend when it moved through water. Consider the appearance of an object protruding through the surface of clear water. The object seems to be displaced. That is, the position where the object, such as a stick, appears to enter the air seems to be different from where it exits the water; and thus it seems to be broken. (We all see this when we look at a drinking straw in a glass of water.) This occurs because light passing through liquid bends. The part of the object in the water is actually in a different position than where it appears to be to the human eye.
This property of light (called refraction) had very practical implications even for primitive peoples. For example, archers hunting for fish with a bow and arrow knew that if they aimed directly at the fish in the water they would always miss. Rather, if they aimed slightly below the fish, that fish would be dinner. The same thing did not work for prey in the air. Shooting arrows under birds did nothing but scare them.
Likewise, refraction is responsible for the magnification produced by droplets of water on leaves or other surfaces. Following the discovery of clear glass,1 the magnification of water droplets could be simulated (and made permanent) by using droplets of glass. Through forming the clear glass droplets into different shapes, their magnification properties could be altered at will, and a variety of these droplets (i.e., lenses) could be made and used individually or in combination to produce telescopes and other visual instruments. Thus was born the field of optics—the branch of physics that studies the properties of light and its interactions with matter—and the path was made clear for research into the properties of light, the only type of radiation known at that time.
Before that falling apple and gravity got his attention, the first scientific passion of Isaac Newton (1643–1727) was optics.2 In his laboratory, Newton made a number of novel observations about the properties of light. For example, he discovered that white light is composed of colored light blended together.3 As he demonstrated, white light can be separated into its colored components with the use of a glass prism. This occurs by virtue of a light-bending effect known as dispersive refraction, whereby various wavelengths of light (i.e., different colors) bend slightly differently when passing through the prism; and thus the wavelengths separate from one another.
Newton used manmade prisms as light-bending tools for many of his optical experiments and demonstrations on the properties of light. However, the most dramatic evidence of a prism effect is the natural separation of sunlight into the colors of the rainbow by a large volume of water droplets, as can be seen in the sky following a storm. Unfortunately, Newton’s experiments with light rays were limited by his senses. He couldn’t measure what his eyes couldn’t see. He didn’t know that beyond those colored rays there was a universe of invisible rays that he could not sense or detect.
Later, scientists were fascinated by another phenomenon often associated with storms. This was electricity. Ever since the time of the apocryphal story of Benjamin Franklin flying a kite in the lightning storm, the public had been generally aware of the existence of electricity and what it could do. Besides killing people and burning down barns, in weaker forms it could produce sparks and even make the hair on one’s head stand up. Electricity could also be generated simply by rubbing two different materials together (i.e., static electricity). So one didn’t need to wait for a storm in order to play with electricity. In fact, small static-electricity machines were highly popular parlor toys for the aristocrats of Franklin’s day.
Investigations of light and electricity ran in parallel paths. Yet, it wasn’t until the late 1800s that the connection between light and electricity would begin to be understood and then developed into practical uses for the general public.
A BRIGHT IDEA
Contrary to common wisdom, Thomas Alva Edison (1846–1931) did not invent the first electric light bulb. That had been invented by Humphry Davy (1778–1829) in approximately 1805, and was called an arc lamp. Arc lamps produce light in a glass bulb in the form of intense brilliant white sparks that are produced in rapid succession. Arc lamps were suitable for outside illumination from tall lampposts, and such lampposts were in common use in public areas of major cities in Edison’s day. But the arc lamp was simply too bright for use in the home.4 A different approach would be needed to bring electric lighting into homes.
Edison knew, as did others, that running electricity through a variety of materials could make those materials glow—a process called incandescence—thereby producing a light source that could be used as an alternative to candles and natural gas lamps. The problem was that the glowing material (the filament) would degrade after a short while, making its use as a household lighting device impractical. Not knowing any of the physical principles by which electricity destroyed the filament, Edison simply tried every material he could to see if one would glow brightly, yet resist burning out. After trying 1,600 different materials, including cotton and turtle shell, he happened upon carbonized bamboo, which turned out to be the filament of choice (to the joy of turtles everywhere).5 When used in an air-evacuated bulb (i.e., a vacuum tube), the carbonized bamboo outshone and lasted much longer than any of the other tested filaments. Edison had his light bulb. Although tungsten soon replaced carbonized bamboo in home light bulbs, illumination by inc
andescence became the predominant mode of interior lighting for many decades to follow.
Despite its potential for lighting homes, the electricity that powered light bulbs was initially looked upon with great fear and suspicion by the public. And the public had good reason to be wary. Newspaper reports of people being electrocuted were common. Pedestrians were, understandably, frightened by the spider webs of telegraph and electrical wires that loomed ominously over city streets, just waiting to fall on an unsuspecting passerby and end his life in a literal flash. In fact, many witnessed an accidental electrocution in midtown Manhattan in April 1888. A 17-year-old boy was struck dead when a dangling wire from overhead brushed against his body as he walked along Broadway. The New York World disgustedly reported, “Right on Broadway, where thousands and thousands of people are passing during all hours of the day, scores of wires are swinging in mid-air, any one of which is likely to become dislodged!”6
One of the paradoxes about electricity was that, despite its extremely swift lethality, it usually left its victims unmarked. It seemed to be a mysterious and spooky kind of death, where the life forces were simply sucked out of its victim without visible damage to organs or body parts. It was remarked that one victim seemed to have died simply from a hole in his thumb, where he had touched the wire. There was little understanding of the mechanisms of death by electrocution, and this heightened the fear of it.7 This lack of understanding likely explains the enormous public outrage regarding accidental electrocutions, while other technology-related deaths went without notice. For example, in 1888, in addition to that 17-year-old boy, there were only four other electrocution deaths in New York City, while there were 23 deaths due to natural gas, and 64 deaths caused by streetcars. The gas and streetcar deaths were simply too ordinary to raise public concern.8
Edison, however, saw the public’s fear as an opportunity. He had already tried to use fear of gas fires to promote electric lights over gaslights. Now he would use the fear of electrocution against business rival George Westinghouse (1846–1914).
Westinghouse was Edison’s chief competitor in the delivery of electricity to homes, and was the king of overhead street wires. He found that wiring overhead, rather than underground, was vastly cheaper to install and maintain. Edison had chosen to use underground wiring for his electrical transmission lines, and the cost of digging trenches for wires was driving him out of business. Westinghouse was also exploiting another technological innovation to Edison’s detriment by using alternating current (AC) rather than direct current (DC) for power transmission.9 The AC could travel much greater distances than DC, thus reducing the number of generating stations that were required for any geographic area and also allowing transmission of electricity to areas remote from any generator. Westinghouse had bought a large number patents for AC-based inventions from another of Edison’s rivals, Nikola Tesla (1856–1943), all of which would become worthless if DC became the standard.10 Since the public’s fear of electricity was closely associated with overhead wires, and those wires were largely conducting Westinghouse’s AC, Edison began a campaign to redirect that fear to the AC current rather than the overhead wiring. According to Edison, AC was deadly, and DC current (his own product) was a much safer alternative.
To demonstrate AC’s lethality, Edison performed a number of public electrocutions of dogs and other animals. In 1903, he even went so far as to use AC to euthanize a temperamental female circus elephant named Topsy. The elephant had been brought to America as a juvenile in 1885 to perform in the Adam Forepaugh Circus, which was a competitor of Ringling Brothers. Unfortunately, as she grew, she became temperamental and killed three of her handlers. The circus planned to put her down, but not before finding up-front buyers for her various body parts. Once the financial deals were complete, the circus needed a means to kill her without damaging the body parts they had already sold. They decided on a public hanging, and even built an enormous scaffold at Coney Island, New York, to perform the deed. But the Society for the Prevention of Cruelty to Animals (SPCA) soon got wind of the plan and intervened.11 The SPCA contended that it was impossible to kill a six-ton elephant quickly by hanging, and the job was sure to be botched, resulting in pain and suffering to the elephant. At this point, the story reached the newspapers and the attention of Edison. His solution for the circus’s predicament was AC electrocution.
Edison sent a team of workers to Coney Island with copper-clad sandals for the elephant’s feet. After being affixed with the sandals, the elephant was jolted with 6,000 volts of AC. Before a crowd of 1,500 onlookers, Topsy staggered and fell to the ground dead, amidst smoke rising from her feet.12
The crowd was duly impressed with AC current’s power to kill. They might have been less impressed, however, had they known that the elephant was also fed carrots laced with cyanide minutes before the electrocution. Whether by cyanide or AC, the elephant died quickly and Edison was pleased, as were the body-part merchants. Despite Topsy’s feet being burnt, they were in good enough shape to make nice umbrella stands. To further give the event an aura of scientific authenticity, the unsellable internal organs were donated for anatomical studies to Professor Charles F. W. McClure (1852–1944) of the biology department at Princeton University.
TOPSY-TURVY
Westinghouse responded to Edison’s accusation about the lethality of AC with his own unfounded accusations about the dangers of DC (e.g., higher household voltages required for DC would result in more deaths). Ironically, both men also claimed health benefits for their own currents. Westinghouse claimed the AC’s momentary reversal of current “prevents decomposition of tissue.”13 Edison once marketed a DC-powered product, called an inductorium, that produced mild electric shocks to the body; it was claimed to be a “specific cure for rheumatism.”14
As the AC/DC health hazard debate began to wind down, Edison made a last ditch effort to sway public opinion on a national level. The execution of Topsy had been preserved as a very short movie by Edison’s motion picture crew. Edison released it to the public as a silent film entitled “Electrocution of an Elephant,” and it was widely distributed to audiences throughout the United States.15 (It still can be found as a video on the Internet.16)
Unfortunately for Edison, his plan to scare the public away from AC backfired. All of his public electrocutions of animals proved too much for many to stomach. In addition, Edison had even gone so far as to promote AC as a means of executing humans and had designed an electric chair for the purpose. The chair was first used to execute a condemned prisoner at Auburn Prison in New York State, in 1890. Although Edison had claimed the chair would produce a rapid and painless death, it did neither. The Auburn electrocution did not go as well as Topsy’s at Coney Island. The prisoner had to be jolted multiple times before he died, and his body was badly burned in a slow process that took over eight minutes to complete. Edison was heavily criticized for his prediction that the prisoner would die painlessly in 1/10,000th of a second. Westinghouse said, “They could have done better with an axe.” The bungled execution received wide coverage in the press, and the public was outraged.17
Rather than turn against AC, people turned against Edison. There was a tremendous backlash to these horror spectacles. The great Edison—father of the incandescent light bulb—was subsequently vilified. In the end, Westinghouse’s AC current ultimately won the day as the favored mode of electrical transmission.
Ironically, Topsy fared much better than Edison in the court of public opinion. Her serial killing spree was forgiven, and she came to be seen as a poor victim of technology gone amuck. She became a posthumous celebrity, a poster child for the anti-animal abuse movement, and the subject of the song, “Coney Island Funeral.”18 Most recently, she had a monument dedicated to her memory at the Coney Island Museum in 2003.
The ghost of Topsy may even have exacted its toll on Luna Park, the amusement park where she met her demise. On August 12, 1944, Luna Park burned completely to the ground in a mysterious fire that the locals
called “Topsy’s Revenge.” The cause of the fire remains unknown, but it may have been electrical.
With time, Edison regained his stature as a great inventor, and electric wiring in the home—whether AC or DC—gained wide acceptance. It wasn’t that people necessarily became less fearful of electricity, but rather, as they became more familiar with it, they began to believe that the risks could be managed with some safety precautions. People began to accept the trade-off of the risk of accidental electrocution for better and cheaper illumination and work-saving electrical appliances. They simultaneously experienced a lower risk of candle and gaslight fires. They even ignored a dying gaslight industry’s warning to its few remaining customers that incandescent light projected a toxic ray that would turn their skin green and increase their death rate.19 But this fabricated claim was also seen by the public as the scare tactic that it was—no better than Edison’s rants about AC—and they were unmoved. Gas lighting in homes soon disappeared, and the death rate from house fires decreased accordingly.
As for radiation in the form of electrically produced light, the public feared the invisible electricity, rather than the electric light itself. Once electricity was tamed for human use, however, it was available to generate invisible forms of radiation—some benign and some not. Still, none of these types of radiation would engender as much fear as the electricity itself had … at least not in the beginning.
DOT DASH DOT DOT DASH DASH DOT DOT DOT DOT DASH DASH DASH
Many think that Guglielmo Marconi (1874–1937) discovered radio waves. As is the case with Edison’s electric light bulb, this story is also only half true. Radio waves were predicted and searched for by a number of scientists working over a number of years. Marconi, however, had the good fortune of showing up just as everything was coming together and, more importantly, he immediately grasped the practical implications of the work. Thus, he took a lot of the fame and glory, as well as the 1909 Nobel Prize in Physics. The other important players, including Oliver Joseph Lodge (1851–1940), a physics professor at University College of Liverpool, England, remain more obscure. Regrettably, such is the life of a scientist. Still, it is important to reflect on why the scientists suspected the existence of radio waves and why they began to hunt them down.
Strange Glow Page 2
