Scientific American Magazine
Cover; January 1998; Scientific American Magazine; by Staff Editor; 1 Page(s)
Table of Contents; January 1998; Scientific American Magazine; by Staff Editor; 2 Page(s)
From the Editors; January 1998; Scientific American Magazine; by Rennie; 1 Page(s)
A recent stamp of acceptance given to acupuncture by the National Institutes of Health lends extra currency to this month's article "The Placebo Effect," by Walter A. Brown (page 90). A review panel organized by the NIH has endorsed the use of acupuncture as an alternative or complementary treatment for a miscellaneous host of ailments, including nausea from chemotherapy, lower back pain, dental pain, asthma, tennis elbow and carpal tunnel syndrome.
This development will not end the controversy over acupuncture's purported benefits, nor should it. Critics have argued that the review panel, while independent, lacked any voices sufficiently skeptical of the claims for acupuncture. And the panel itself recognized that better, more thorough trials are needed to test the technique's real therapeutic benefit. The best that can be said at present is that against some medical conditions, acupuncture seems to do no harm and may bring relief, although no one has more than a vague idea of how.
Letters to the Editors; January 1998; Scientific American Magazine; by Staff Editor; 1 Page(s)
Thank you for publishing Elizabeth Loftus's article "Creating False Memories" [September 1997]. People need to be educated about the pain that can be caused by overzealous therapists. In June 1991 our then 30-year old daughter began seeing a therapist for depression following her divorce. After seeing her for less than a month, this man analyzed her dreams and told her that the depression was from repressed memories of sexual abuse. Since then, she has broken all contact with us. Her siblings, however, do not believe the accusations. We have not only been falsely accused of a horrible crime, we have also lost a child.
Loftus's interesting article may leave readers with the impression that most allegations of abuse are inculcated by manipulative therapists. My daughter, who has Down syndrome, was molested for four years by her father, my ex-husband. Although I had begun to suspect him from her sexualized behavior and from the fact that there were no other opportunities in her protected life for sexual abuse to occur, it was impossible for me to believe that her father would do such a thing until I heard my daughter explicitly describing one of his acts and crying softly to herself that she loved him, that it couldn't be "that bad." We are all capable of embellishing the truth and, in some cases, inventing it under the power of repeated suggestion. But to make any generalizations about the incidence of child abuse based on a few spectacular cases of unscrupulous therapists is unfair to the many children who have been molested.
50, 100 and 150 Years Ago; January 1998; Scientific American Magazine; by Staff Editor; 1 Page(s)
JANUARY 1948 THE NEW SCIENTIFIC AMERICAN--Under new ownership and a new board of editors, the 103-year-old Scientific American is to become a magazine of all the sciences, covering the physical, biological and social sciences as well as their more significant applications in medicine and engineering.
AIRBORNE PROSPECTING--Until recently geophysicists researching the earth¿s magnetic field sent out survey parties with a magnetometer. Frequently the party had to hack its way through the bush to collect data. It was slow, expensive work. Today geophysicists can use a dramatic refinement of this old method--the airborne magnetometer. Carried by an airplane traveling at 125 miles per hour at an altitude of up to 1,500 feet, the airborne magnetometer can deliver accurate data on new oil and mineral resources at a rate of up to 10,000 square miles per month.
The 1997 Nobel Prizes in Science; January 1998; Scientific American Magazine; by Staff Editor; 4 Page(s)
This year¿s physics prize rewards those who found a way to trap neutral atoms and then cool them to within a whisper of absolute zero. The idea had existed at least since the 1970s, when researchers proposed using lasers and magnetic and electrical fields to trap charged particles such as beryllium ions. Trapping neutral particles, however, is much more difficult because they do not feel the effects of electromagnetic fields.
In 1985 Steven Chu, then at Bell Laboratories in Holmdel, N.J., and his colleagues placed sodium atoms in a vacuum chamber and surrounded them with six laser beams. The force exerted by the laser photons slowed the atoms. Chu found that the "optical molasses" chilled the atoms to 240 microkelvins (240 millionths of a Celsius degree above absolute zero), slowing them to about 30 centimeters per second (atoms in a room-temperature gas, in contrast, zip along at more than 100,000 centimeters-- one kilometer--per second).
In Focus: Burying the Problem; January 1998; Scientific American Magazine; by Schneider; 2 Page(s)
In December world leaders gathered in Kyoto, Japan, to grapple with the growing threat of global warming caused by the burning of fossil fuels. To combat the surge in greenhouse gases-- chiefly carbon dioxide--researchers and policymakers have called for energy conservation, taxes on carbon emissions and the swift development of renewable energy sources, such as wind and solar power. Still, with nuclear energy out of favor and no easy replacement for fossil fuels on the horizon, the rise in atmospheric carbon dioxide might appear unstoppable. But a growing number of scientists are pointing out that another means of combating greenhouse warming may be at hand, one that deals with the problem rather directly: put the carbon back where it came from, into the earth.
The idea of somehow "sequestering" carbon is not new. One method is simply to grow more trees, which take carbon from the atmosphere and convert it to woody matter. Although the extent of plantings would have to be enormous, William R. Moomaw, a physical chemist at Tufts University, estimates that 10 to 15 percent of the carbon dioxide problem could be solved in this way.
Extreme Science; January 1998; Scientific American Magazine; by Gibbs; 2 Page(s)
On board the icebreaker Des Groseilliers, the night seems eerily quiet, still and warm. There is no throaty rumble of engines, although the ship is moving. No pitch or roll, although we are floating in the Arctic Ocean just 1,000 miles from the North Pole. No biting chill, despite winds blowing outside at ¿30 degrees Celsius. The propellers that plowed this Canadian Coast Guard vessel into the heart of a five-mile-wide, six-foot-thick chunk of the polar ice cap stopped turning 12 days ago, on October 2. The hull is now encased in thick, azure ice on all sides. If the 50 scientists from 17 research institutions who are on board get their wish, it will stay that way until late October--of 1998.
From the air, the Des Groseilliers looks like a 322-foot-long Gulliver fallen in the snow, lashed by bundles of copper cable and optical fiber to a surrounding hamlet of squat huts and spindly instrument towers. It is for all intents no longer a ship but a hotel, power plant and command center for Ice Station SHEBA. The yearlong SHEBA (Surface Heat Budget of the Arctic Ocean) expedition, funded primarily by the National Science Foundation, is measuring how heat flows between sun, clouds, air, ice and ocean within a typical 39-square-mile patch of the Arctic.
Don't Stress; January 1998; Scientific American Magazine; by Leutwyler; 2 Page(s)
Most people do not share Chicken Little¿s fear of falling skies. Stress is, after all, largely subjective. Nevertheless, it does prompt a series of marked physiological changes: The adrenal gland cranks out steroids that mobilize sugars and fat reserves. Additional hormones curb growth, reproduction and other nonessential activities to conserve energy. And the brain produces more epinephrine to ready the heart and other muscles for action.
In the face of danger, this short-lived reaction helps you survive. If the stress response is regularly tripped for the wrong reasons, however, it has the opposite effect. Indeed, researchers have known for some time that chronic stress often leads directly to certain illnesses, including heart disease, hypertension, depression, immune suppression and diabetes. Recently they have discovered that stress also causes developmental abnormalities, unhealthy weight gain and neurodegeneration. Fortunately, some of these new insights suggest better means for combating excess stress.
In Brief; January 1998; Scientific American Magazine; by Leutwyler; 3 Page(s)
Bird Brains-- Some bird brains are bigger than others, researchers at the University of Washington now say. Doctoral student Tony Tramontin, collaborating with psychology and zoology professors, examined the growth of brain regions that white-crowned sparrows use for singing. Previously, scientists thought that lengthening days and corresponding hormonal changes controlled the development of these regions in seasonally breeding birds. But Tramontin found that social cues held equal sway. Indeed, in male birds living with females, the brain regions grew 15 to 20 percent larger than they did in male birds living alone or with other males. It is the first observation of socially induced changes in the avian forebrain.
A Quick Glucose Test-- Scientists at the Mayo Clinic in Rochester, Minn., have announced that in preliminary tests, a new device for measuring glucose levels in diabetics performed as well as blood tests did. The workers tested 67 adult volunteers using a new device that collects a sample of skin fluid byway of a tiny needle. They also tested the glucose levels in these volunteers by the finger-stick method. They found that both the skin-fluid sample and the finger- stick measured the correct glucose levels with an accuracy of 97 percent.
Ancestral Quandry; January 1998; Scientific American Magazine; by Wong; 2 Page(s)
After researchers published the first analysis of ancient human DNA in the journal Cell last July, the case was closed, or so it seemed. "NEANDERTHALS WERE NOT OUR ANCESTORS" read the cover, featuring a photograph of the archetypal specimen¿s skullcap with its heavy, arched browridge so unlike our own relatively smooth brows. The pattern of differences between Neanderthal and modern DNA indicated to the team that Neanderthals were an evolutionary dead end, replaced by modern humans without any interbreeding. Popular accounts hailed the research as proof of a recent African origin for all modern humans, but has the long-standing debate over human origins really been put to rest? Judging from subsequent reactions among geneticists and paleoanthropologists, apparently not.
The Cell paper supports the so-called out-of-Africa model of human evolution put forth by paleoanthropologist Christopher B. Stringer of London¿s Natural History Museum. It states that modern humans originated in Africa 130,000 to 200,000 years ago and spread from there less than 100,000 years ago, replacing archaic populations such as Neanderthals all over the world. The competing hypothesis is multiregional evolution, championed by University of Michigan paleoanthropologist Milford H. Wolpoff. It holds that humans arose in Africa some two million years ago and evolved as a single, widespread species, with multiple populations interconnected by genetic and cultural exchanges.
Anti Gravity: Tender is the Bite; January 1998; Scientific American Magazine; by Mirsky; 1 Page(s)
John Long hails from a time when nonspecialists did lots of varied and interesting science. He was a meteorologist during World War II. In the late 1940s he engineered robots ("We used to call it remote-control equipment," he says) to handle radioactive metallurgy for Glenn T. Seaborg¿s work discovering new elements and later started his own business developing those robots. In the late 1950s he went to Lawrence Livermore National Laboratory, where he remained for the rest of his official career in nuclear weapons design. There Long discovered that conventional weapons were superior at tenderizing meat.
Long worked with an experimental setup that called for a small conventional explosive to be detonated underwater, creating shock waves. A wire needed to be replaced in the setup after each explosion. Long wondered what would happen if some snakebit technician stuck his hands in the water to change a wire that was still good and was subjected to an accidental explosion. "I got to thinking, ¿Gee, the shock wave is just going to travel through the flesh--it would probably be fatal,¿ " Long recalls by telephone last November 3, his 78th birthday.
By the Numbers: Women in Politics throughout the World; January 1998; Scientific American Magazine; by Doyle; 1 Page(s)
The markedly uneven participation of women in public life is illustrated by the map, which shows the proportion of female-held seats in national legislatures. Data are shown only for lower houses or for single houses in the case of those countries that have no upper house. Lower houses of legislatures, as in the U.S. and the U.K., are generally more representative of the electorate.
Women¿s participation in the national legislatures of Western democracies has been growing since the end of World War II, slowly in some places, such as the U. S., and dramatically in others, such as Sweden. In the U.S., France, Italy and Ireland, 12 percent or less of lower-house seats are now held by women, whereas in other places, such as the Nordic countries, Germany and the Netherlands, women hold more than a quarter of the seats. These differences reflect sharply divergent cultural traditions, such as the American tendency toward conservative religion, which has a traditional view of women¿s roles. Americans emphasize freedom at the expense of equality and so tend to neglect economically disadvantaged groups, such as women and blacks. On the other hand, Scandinavians and others have traditionally put social justice for groups ahead of economic freedom for individuals. Other factors promoting women¿s participation are proportional representation (losing parties still get to send delegates) and a parliamentary, multiparty system, both of which exist in Sweden, where each of seven parties won substantial blocks of votes in the 1994 parliamentary elections.
Profile: From Naked Men to a New-World Order; January 1998; Scientific American Magazine; by Gibbs; 2 Page(s)
Outside Claude L¿vi-Strauss¿s office building in the Latin Quarter of Paris, chaos rules. Amid a haphazard jumble of institutes, bookshops and caf¿s, mopeds and improbably tiny cars weave through the narrow streets, dodging knots of university students, all of whom seem, like myself, to be five minutes late for some crucial appointment.
Inside the Laboratory for Social Anthropology, the sense of order is palpable. As I climb the stairs to a mezzanine office, each step seems to lead not only up in space but also back in time. The door to the office opens, from all appearances, into the 19th century. Here, in his isolated aerie adorned with enclosed bookcases and exotic curios beneath bell jars, L¿vi-Strauss is perched at an antique desk. As I apologize for my tardiness, he looks at me quizzically, as if time is irrelevant, and moves over to his picture window overlooking the regiment of oversized file cabinets that nearly fill the laboratory below. Crowning them on the far wall is an ornate arching banner inscribed Pour la Patrie, les Sciences et la Gloire--For the Fatherland, the Sciences and the Glory.
Off with its Head!; January 1998; Scientific American Magazine; by Zorpette; 1 Page(s)
In the wake of a British biologist¿s assertion that he had created frog embryos that failed to grow a head, many of the alarmed pronouncements that made their way into the popular media seemed to have been informed by the weirder veins of pulp science fiction rather than by scientific plausibility. Press reports conjured up imagery of human organs growing in bottles and even mutant human "organ sacks" grown from headless embryos and kept alive artifi- cially for the sole purpose of storing organs for harvesting and transplantation. At about the zenith of surreality, a former director of the National Institutes of Health reportedly noted on the CBS Evening News that a headless embryo would "have zero potential to say no."
Many biologists and ethicists, however, are far more troubled by the flights of morbid fantasy, which they say could have a chilling effect on potentially beneficial research. Some were also disturbed by what they perceive as the role of Jonathan Slack, a developmental biologist at the University of Bath, in fostering the wild speculation. "Slack unleashed a torrent of silliness at the expense of the scientific community," charges Arthur Caplan, an ethicist at the University of Pennsylvania. Slack declined to be interviewed for this article.
Laser Show; January 1998; Scientific American Magazine; by Dupont; 1 Page(s)
In early October U.S. Defense Secretary William S. Cohen announced he would allow the army to fire a massive laser beam at an aging air force tracking satellite 260 miles above the earth. The Pentagon emphasized the defensive nature of the test by stating that the main goal was to gather data about the vulnerability of U.S. satellites to laser attacks.
Few were convinced. For years the army believed its Mid-Infrared Advanced Chemical Laser (MIRACL) at the White Sands Missile Range in New Mexico had the potential to disable satellites, but a congressional ban kept the service from testing the hypothesis. After a Republican-led Congress let the ban drop, however, the army proposed a test of MIRACL¿s ability to "negate satellites harmful to U.S. forces." Only after extensive press coverage and congressional criticism did the Pentagon announce the emphasis of the test had shifted from antisatellite (ASAT) experimentation to the assessment of the vulnerability of the air force target satellite, which had been selected because it could report back on any damage from the laser. After several mishaps, the army fired at the target satellite in late October; problems with both the laser and the satellite, however, kept the Defense Department from attaining much data.
New Silicon Tricks; January 1998; Scientific American Magazine; by Hayashi; 2 Page(s)
For decades chipmakers have operated on the simple premise that smaller is better. But as silicon transistors continue shrinking to the tiniest of dimensions--reducing the distance electrons have to travel and thus speeding up calculations--problems such as current leakage become acute.
Looking for a different way to add zip to silicon, scientists have been working with variations of the material that could conduct current faster. The latest: adding carbon to a mix of silicon and germanium. Various research centers, including Princeton University, the Institute for Semiconductor Physics in Germany and the University of Texas at Austin, have used carbon to fabricate transistors of reasonable circuit sizes that could lead to silicon-based chips operating in the gigahertz range--some 1,000 times faster than they do now. "We¿ve been trying to teach an old dog new tricks," says James C. Sturm, director of Princeton¿s Center for Photonics and Optoelectronic Materials.
Roaches at the Wheel; January 1998; Scientific American Magazine; by Yam; 1 Page(s)
Researchers in Tokyo received some notoriety last year when they showed how implants could govern the movements of a cockroach--the idea being that such roboroaches could be used for covert surveillance or for searches through wreckage. Now one engineer has worked the flip side of that relationship: a robotic vehicle controlled by a cockroach.
Hajime Or built what he calls a "biomechatronic robot" while working on his master¿s degree at the University of Tokyo last year. After taping down an American cockroach (bottom left), he inserted fine silver wires into the extensor muscles of the hind legs. The roach was then allowed to run on what amounts to a trackball (bottom right). The wires picked up the weak electrical signals generated by the muscles, and the signals were amplified and fed to the motorized wheels. In this way, the machine would mimic the speed and direction the cockroach ran.
Cyber View; January 1998; Scientific American Magazine; by Grossman; 1 Page(s)
Ever since the word was first used in 1960 to describe how machines could enable humans to survive hostile environments, cyborgs have lived with us in science fiction. For instance, Star Trek presented a blind character who "saw" via a sensor array embedded in her clothing. Such vision may not be far off, as shown in three days of demonstrations of wearable computers held at the Massachusetts Institute of Technology last October.
Items included jewelry that flashed in time with your heartbeat, a musical jacket with a keyboard near the breast pocket and digital versions of the mood ring: Rosalind W. Picard, a researcher studying "affective computing," embedded sensors in earrings and Birkenstock sandals to identify and respond to the emotional states of the wearer. More than just a nerd playland, the conference suggested how wearable computers have uses that, despite some appearances, go beyond mere entertainment.
The Architecture of Life; January 1998; Scientific American Magazine; by Ingber; 10 Page(s)
Life is the ultimate example of complexity at work. An organism, whether it is a bacterium or a baboon, develops through an incredibly complex series of interactions involving a vast number of different components. These components, or subsystems, are themselves made up of smaller molecular components, which independently exhibit their own dynamic behavior, such as the ability to catalyze chemical reactions. Yet when they are combined into some larger functioning unit--such as a cell or tissue--utterly new and unpredictable properties emerge, including the ability to move, to change shape and to grow.
Although researchers have recognized this intriguing fact for some time, most discount it in their quest to explain life¿s fundamentals. For the past several decades, biologists have attempted to advance our understanding of how the human body works by defining the properties of life¿s critical materials and molecules, such as DNA, the stuff of genes. Indeed, biologists are now striving to identify every gene in the complete set, known as the genome, that every human being carries. Because genes are the "blueprints" for the key molecules of life, such as proteins, this Holy Grail of molecular biology will lead in the near future to a catalogue of essentially all the molecules from which a human is created. Understanding what the parts of a complex machine are made of, however, does little to explain how the whole system works, regardless of whether the complex system is a combustion engine or a cell. In other words, identifying and describing the molecular puzzle pieces will do little if we do not understand the rules for their assembly.
Burial of Radioactive Waste under the Seabed; January 1998; Scientific American Magazine; by Hollister, Nadis; 6 Page(s)
On the floor of the deep oceans, poised in the middle of the larger tectonic plates, lie vast mudflats that might appear, at first glance, to constitute some of the least valuable real estate on the planet. The rocky crust underlying these "abyssal plains" is blanketed by a sedimentary layer, hundreds of meters thick, composed of clays that resemble dark chocolate and have the consistency of peanut butter. Bereft of plant life and sparsely populated with fauna, these regions are relatively unproductive from a biological standpoint and largely devoid of mineral wealth.
Yet they may prove to be of tremendous worth, offering a solution to two problems that have bedeviled humankind since the dawn of the nuclear age: these neglected suboceanic formations might provide a permanent resting place for high-level radioactive wastes and a burial ground for the radioactive materials removed from nuclear bombs. Although the disposal of radioactive wastes and the sequestering of material from nuclear weapons pose different challenges and exigencies, the two tasks could have a common solution: burial below the seabed.
Bacterial Gene Swapping in Nature; January 1998; Scientific American Magazine; by Miller; 6 Page(s)
In the early 1980s, as scientists were perfecting techniques for splicing foreign genes into bacteria, some investigators began suggesting ways to use the technology to benefit the environment. For instance, they proposed that genetically engineered bacteria might be deployed for such tasks as cleaning oil spills or protecting crops from predation and disease. But the enterprise, known as environmental biotechnology, soon came under fire.
Then, as now, the proposals elicited concern that the altered microbes might run amok or that their genes would hop unpredictably to other organisms--a phenomenon termed "horizontal" gene transfer (to distinguish it from the "vertical" transfer occurring between a parent and its offspring). Such activities, it was feared, might somehow irreparably harm the environment, animals or people. Some observers even issued dire warnings that the unnatural organisms would destroy the earth. No longer were tabloids worried about attacks by "killer tomatoes" from outer space; now the danger was homegrown-- genetically altered microorganisms that would eat the environment.
The Ulysses Mission; January 1998; Scientific American Magazine; by Smith, Marsden; 6 Page(s)
Although explorers have been traveling around the world for the past 500 years, it was not until the 20th century that a few hardy souls first trudged across the frozen wastes of the Arctic and Antarctic to reach the North and South poles. Curiously, exploration of the solar system has followed a similar pattern. For much of the past four decades, the scientific probes sent into space stayed relatively close to the equatorial plane of the sun, which contains the orbits of Earth and other planets. But a few years ago a single craft, Ulysses, ventured out of that thin zone and into the "polar regions" of interplanetary space.
The reasons researchers waited so long to investigate this realm have more to do with the vagaries of spaceflight than a lack of attention. Indeed, scientific interest in making such a journey has been quite keen. Astronomers have known for decades that the sun is surrounded by a diaphanous outer atmosphere (called the solar corona) that extends past the orbit of Earth. And they realized that the gases in the tails of comets always point away from the sun because they are pushed by the corona as it streams rapidly outward, a flow called the solar wind. Until recently, however, scientists have been unable to sense how the material emanating from around the poles of the sun courses through the interplanetary vastness.
Lise Meitner and the Discovery of Nuclear Fission; January 1998; Scientific American Magazine; by Sime; 6 Page(s)
When scientists first recognized, in late 1938, that a neutron could split an atom¿s core, the discovery came as a complete surprise. Indeed, no physical theory had predicted nuclear fission, and its discoverers had not the slightest foreknowledge of its eventual use in atomic bombs and power plants. That much of the story is undisputed.
The question of who deserved credit for the breakthrough, however, has long been debated. Physicist Lise Meitner and two chemists, Otto Hahn and Fritz Strassmann, conducted a four-year-long investigation that resulted in the discovery of fission in their laboratory in Berlin. Meitner fled Nazi Germany in 1938 to escape the persecution of Jews, and soon after, Hahn and Strassmann reported the discovery. Meitner and her nephew, Otto R. Frisch, published the correct theoretical interpretation of fission a few weeks later. But the 1944 Nobel Prize in Chemistry was awarded to Hahn alone.
Picosecond Ultrasonics; January 1998; Scientific American Magazine; by Maris; 4 Page(s)
During the past three decades, humans have developed a remarkable ability to manufacture small objects. A prime example is the computer chip, made from a silicon wafer with strategically placed impurities that form transistors. On top of each chip is a sequence of metal films and insulating layers that electrically connect the transistors to their neighbors. The films may be as thin as a millionth of a centimeter. Their thickness and uniformity determine the efficiency of the chip and, ultimately, the computer it is in.
A film may be anywhere from 50 angstroms to a few microns thick (one angstrom equals 10-8 centimeter, whereas one micron equals 10-4 centimeter). For the finest films, the thickness has to be controlled to an accuracy of one angstrom-- less than the size of an atom. Measuring the thickness is exceedingly difficult. The most efficient means currently available is destructive: take a chip, cut it and look at it from the side. Most manufacturers deal with the problem of ensuring consistent thickness by minutely controlling every aspect of the production process--such as temperature, humidity and pressure--and by checking the dimensions of the few chips that are sacrificed.
The Placebo Effect; January 1998; Scientific American Magazine; by Brown; 6 Page(s)
After a day of crosscountry skiing in subfreezing weather a couple of years ago, I developed severe lower back pain. Even tying my shoes was agony. Despite my suffering, I knew there was no serious underlying disease, so I was certain I would be back to normal in no time.
But the days wore on with no change. A heating pad and suggestions from a friend with a chronic back problem (lie down, tuck your chin when you bend over) didn¿t help. After a week, I became desperate. I called my cousin Gary, who is a physical therapist. When I have consulted him in the past about sprains and tendonitis, his advice has always been on target. I was confident I was in the hands of an expert.
Leonardo and the Invention of the Wheellock; January 1998; Scientific American Magazine; by Foley; 6 Page(s)
According to legend, the great Italian artist and inventor Leonardo da Vinci died while pleading, "Tell me if anything at all was done." Although historians dispute the specifics of this story, this phrase does appear in Leonardo¿s notebooks, implying that he regretted he had not accomplished more in his lifetime.
The question of how much Leonardo achieved during his 67 years (1452-1519) has resurfaced among current scholars of Renaissance engineering. When Leonardo¿s manuscripts were first published at the end of the 1800s, readers were amazed by pages crammed with inventions that were not built until hundreds of years later. Yet by the middle of the 20th century, views had shifted. Historians such as Bertrand Gille and Leonardo Olschki pointed out Leonardo¿s great debt to earlier Renaissance engineering manuscripts and suggested that he was merely a derivative figure.
The Amateur Scientist; January 1998; Scientific American Magazine; by Carlson; 2 Page(s)
Biochemists have always amazed me. Using mostly straightforward, inexpensive methods, these gifted researchers somehow manage to unlock many of the mysteries of life. And although the past decade has seen powerful (and expensive) new techniques brought to bear, discoveries are still being made by means that are well within the reach of a dedicated amateur. Sadly, biochemistry is a field that has so far been little explored by amateur researchers, and I think I know why. Few of them have access to what is perhaps the central tool of biochemistry--the centrifuge.
A centrifuge rapidly spins several small test tubes filled with a liquid suspension that is to be separated into its component parts. Like passengers in a car making a high-speed turn, every particle suspended within the tube is thrown outward by its own inertia. Biochemists often take advantage of this effect by adding something to a solution that causes certain components to precipitate. For purifying proteins, for example, this change is often provoked by adding a weak acid or base (vinegar or baking soda, for instance). The high "g forces" generated by the centrifuge then induce the solid particles to settle out in no time flat.
Mathematical Recreations; January 1998; Scientific American Magazine; by Stewart; 4 Page(s)
The dodecahedron has 20 vertices, 30 edges and 12 faces-- each with five sides. But what solid has 22.9 vertices, 34.14 edges and 13. 39 faces--each with 5.103 sides? Some kind of elaborate fractal, perhaps? No, this solid is an ordinary, familiar shape, one that you can probably find in your own home. Look out for it when you drink a glass of cola or beer, take a shower or wash the dishes.
I¿ve cheated, of course. My bizarre solid can be found in the typical home in much the same manner that, say, 2.3 children can be found in the typical family. It exists only as an average. And it¿s not a solid; it¿s a bubble. Foam contains thousands of bubbles, crowded together like tiny, irregular polyhedra--and the average number of vertices, edges and faces in these polyhedra is 22.9, 34.14 and 13.39, respectively. If the average bubble did exist, it would be like a dodecahedron, only slightly more so.
Reviews; January 1998; Scientific American Magazine; by Logsdon, Wallich; 3 Page(s)
In very different ways, these two books examine the space programs of the U.S. and the U. S.S.R. in the 1950s and 1960s and their close relationship to considerations of military security and national power. T. A. Heppenheimer is a professional writer on aeronautics and space topics; Countdown attempts in 350 pages to cover the full sweep of the development of 20th-century rocketry and space exploration. James Harford is an amateur in the classic sense: a gentleman scholar who, motivated by a longtime interest in the evolution of the Soviet space program, wrote his book after retiring from a career in aerospace work. Korolev probes the fascinating career of Sergei Pavlovich Korolev, until his death in January 1966 the anonymous "Chief Designer" of the Soviet missile and space efforts. By portraying how Korolev, through his resourcefulness and ingenuity, shaped the course of Soviet space development, Harford succeeds in letting "some light into the black hole of the Soviet social, political, and technological system in the pre-glasnost days."
Both books look back to an era when space achievements excited the public imagination and showcased a nation¿s technological and organizational competence. They demonstrate that the space race was real: accomplishments--even anticipated ones--by one country were a direct spur to a competitive response by the other. If there was ever any doubt that politics, pride and power, not a vision of an expansive future in space, provided the drive for the initial years of space activity, these books will lay that impression to rest. Space exploration, given its exorbitant costs, had to serve the highest interests of the state; no leader was ready to spend national wealth on journeying to the planets for the sake of human destiny.
Commentary: Wonders - Wildfire; January 1998; Scientific American Magazine; by Morrison, Morrison; 2 Page(s)
As fire is no part of the mineral kingdom, we find it surprisingly apt to discuss it as though it were one among the kingdoms of living things. Copious fire arose only after life crossed the margins of its watery world and came to thrive on dry land, under air of near-modern oxygen content, a state reached after 90 percent of earth history had passed.
We can divide fire, like the grasses, into wild and domesticated forms, both of them very widespread. Wildfire is not always truly wild. Like the cereal grasses, it may have been molded by human intervention and yet may still bloom under the open sky. Fully domesticated fire is different: its myriad species dwell confined within firebox, furnace or engine cylinder. Other forms that one might term fire--say, volcanoes and polar auroras--are less akin to life and remain outside the scope of this piece.
Commentary: Connections - Anybody Out There?; January 1998; Scientific American Magazine; by Burke; 2 Page(s)
We were having a bit of harmless fun the other evening after dinner, doing a little table rapping and glass moving, and somebody suggested we have a go at seeing if Charles Darwin was around. We did. He wasn¿t. Point being, somebody in our s¿ance parlor party had been reading about the great unsolved mystery over who came up first with the idea of evolution.
Was it Darwin or Alfred Russel Wallace, the self-taught surveyor and insect freak? (In eight years in the Malay Archipelago, Wallace collected 125,660 species of creepy-crawly!) In 1858, while in Borneo, Wallace sent Darwin some thoughts on the origin of species and quicker than you could say, "I thought of it first," Darwin had published the Great Book. There are those who have suggested you know what. Perhaps we should have tried contacting Wallace himself. After all, he was a leading light in the spiritualist movement and proclaimed he¿d never seen a medium who was a fraud.
Working Knowledge; January 1998; Scientific American Magazine; by Benton; 1 Page(s)
Ahologram is a recording of a three-dimensional optical image made on very fine grained film using beams of laser light. Unlike photography, which records only the intensity of each light wave reflecting off an object (producing light and dark areas on a film), holography registers both the intensity and the direction, or phase, of the light. Information about intensity and direction is encoded by the degree to which the crests and troughs of the reflected waves are in step with those of a reference wave. Inphase waves produce bright interference patterns, whereas out-of-step waves produce dim patterns.
When white light shines on developed holographic film, the interference patterns act like tiny mirrors positioned at myriad angles. These mirrors bounce light off the surface of the hologram in exactly the same directions at which it originally reflected from the imaged object. Each eye sees a different view because the intensity of the reflected waves varies with their direction, so the observer can perceive depth.