- The Washington Times - Saturday, February 21, 2004

In The Prism and the Pendulum (Random House, $25.95, 224 pages), the philosopher and science historian Robert P. Crease discusses what he calls “the ten most beautiful experiments in science.” A scientific experiment, he tells us, is akin to “a dramatic performance … that people plan, stage and observe in order to produce something they are critically interested in” and it is beautiful if it “shows something deep about the world in a way that transforms our understanding of it” efficiently and definitively.

The 10 classic experiments in the book were originally carried out over a period spanning some 2,200 years, and all of them (except the first) are in physics, which is perhaps related to the fact that they were chosen by polling readers of Physics World magazine.

However, Mr. Crease explains that physics is the prototypical science, and most of the experiments are familiar to people who have studied science at any level. Many of them are still regularly performed, with variations made possible by modern technology, as staples of high school and college labs.

Mr. Crease puts the experiments in perspective by describing his own reactions as a person, and as a philosopher, and by painting short verbal portraits of the experimenters and quoting some of their own words. He proceeds chronologically, beginning with Eratosthenes’ calculation of the circumference of the earth, arrived at by comparing the measured lengths of the shadows cast at noon at two points on the earth’s surface a known distance apart.

He then fast-forwards a millennium and a half to discuss two experiments performed by Galileo Galilei. The first of these disproved Aristotle’s assertion that heavier objects fall faster than lighter ones. Galileo simultaneously dropped two balls of different density from a tower, which may or may not have been the Leaning Tower of Pisa.

Galileo’s other experiment used inclined planes to study accelerated motion under gravity, and we learn that modern researchers now think that Galileo’s musical talents enabled him to measure time more accurately than was credited by an earlier generation of skeptical historians.

Four of the remaining experiments are triumphs of classical physics from the 17th to 19th centuries: Isaac Newton’s decomposition (and reconstruction) of white light using prisms; Henry Cavendish’s incredibly precise measurement of the gravitational attraction between two heavy metal balls in order to determine the density of the earth (and, more importantly, Newton’s gravitational constant); Thomas Young’s proof that light was a wave after producing an interference pattern by passing light through two thin slits; and Jean Bernard Leon Foucault’s use of a pendulum to demonstrate the earth’s rotation by the apparent movement of the pendulum’s plane of motion.

The final three experiments, all performed during the 20th century, are fundamental to atomic physics and quantum theory. Robert Millikan’s oil-drop experiment measured the charge on the electron. Ernest Rutherford’s alpha-particle-scattering experiment showed that the atom was mostly empty space.

Finally, Claus Jonsson (and later several others) performed double-slit experiments on electrons, paralleling Young’s interference experiment with light waves, and produced similar results.

This experiment, Mr. Crease tells us, was the one suggested by far the most often by his respondents. It demonstrates in an unforgettably convincing manner the central mystery of quantum theory — particles that sometimes seem to be points also behave like waves that occupy all space at once.

• • •

A more skeptical view of the experimenter’s art is found in John Waller’s Einstein’s Luck: The Truth Behind Some of the Greatest Scientific Discoveries (Oxford University Press, $30, 307 pages), a work that aims to debunk the received view of major findings.

Like Mr. Crease, this author discusses Millikan’s oil drop experiment, but Mr. Waller — a science historian at University College, London — places his emphasis on Millikan’s decision to use only those observations he thought (correctly) most accurate for calculating his result, while discarding the others, a methodological irregularity that is a definite no-no in the scientific rule book.

The authors agree that Millikan was not a major sinner, since he was quite open about what he had done, and that in the final analysis, his experiment, despite — or perhaps because of — this lapse represented a scientific triumph.

The first part of “Einstein’s Luck” recounts a number of episodes where famous scientists, in Mr. Waller’s words, were “right for the wrong reason,” and used experiments with glaring flaws in their execution to draw conclusions that history subsequently proved correct. One of these eminent figures was Louis Pasteur, whose experiments disproving the spontaneous generation of life were less conclusive than is generally believed.

Another was Arthur Eddington, the prominent Cambridge astrophysicist who was the leading champion in the English-speaking world of Einstein’s general theory of relativity. The conventional view is that the clinching evidence in favor of that theory came from measurements of the bending of starlight passing close by the sun made during an Eddington-inspired expedition to observe the solar eclipse of 1919.

Mr. Waller’s discussion of the actual measurements reveals that they were far too imprecise to confirm Einstein’s calculations. In fact, two sets of observations were taken at different locations, and Eddington emphasized the data from the poorer set, which produced a result closer to Einstein’s prediction, while discarding many of the observations from the better set, which were closer to the predictions of the old Newtonian theory.

Subsequently, more substantial evidence in favor of general relativity has emerged, but it was largely because of Eddington’s unscrupulous massaging of unreliable data that Einstein rose to world fame as the successor to Newton when he did.

Mr. Waller’s iconoclasm extends beyond physics to biology and the social sciences. Among the scientific idols whose clay feet he uncovers are Frederick Winslow Taylor, whose classic text “The Principles of Scientific Management” contains a large admixture of fiction; Joseph Lister, whose concept of antiseptic surgery was not accompanied by a belief that hospital wards and operating theaters had to be kept scrupulously clean; and Alexander Fleming, who did discover the remarkable properties of the penicillin mold but played little part in its transformation into a major lifesaving factor.

If the book has a true villain, it is Charles Best, the Canadian physiologist who in reality played only a minor role in the isolation of insulin but subsequently managed to magnify himself into a major figure. In Mr. Waller’s words, he “not only rewrote the past but pursued those who he felt had stolen his thunder with a malignity that borders on a vendetta.”

• • •

Len Fisher is a physicist at the University of Bristol in England, and in How to Dunk a Doughnut: The Science of Everyday Life (Arcade Publishing, $23.95, 264 pages) he applies the methods and way of thought of a practicing scientist to a variety of subjects of relevance to daily life. The title is slightly misleading, in that he describes his research into dunking cookies rather than doughnuts, but the same principles involving the microscopic structure of the dough apply to each delicacy.

Mr. Fisher also discusses how long one should boil an egg or cook a piece of roast beef, how different hand tools can be used most effectively, and how to closely estimate a long supermarket bill without adding up the cents. The author is an expatriate Australian, and other topics he elucidates include what scientists have discovered about throwing boomerangs and about the structure of beer foam.

The book is an entertaining and relatively painless introduction to the way scientists think. It is not completely painless, however, because some of the explanations are quite technical, and while they are explained in simple language, understanding them requires some thought.

Jeffrey Marsh has written widely on scientific topics and public issues ranging from nuclear strategy to social policy.

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