Experiments as things of beauty

This book is misnamed. "The 10,000 Most Beautiful Experiments" would have been more accurate. Virtually every experimental result in the book is actually the sum of many experiments. Scientists' "Eureka!" moments come not with a single brilliant experiment but after months, or even years, of grinding lab work. This is evident in almost every chapter, from Galileo's lengthy research on falling objects to Luigi Galvani's seemingly endless experiments on how electrical currents make dead frogs' legs twitch.

George Johnson, who writes about science for the New York Times and other publications, has a smooth conversational style. He nicely captures the drudgery and frustrations of scientific experimentation and comes up with important observations about the nature of cutting-edge lab work.

He also throws in some interesting and little-known asides. For example, who knew that Ada Lovelace -- Lord Byron's daughter -- was enamored of Michael Faraday, the deeply religious man who invented, among other things, the electric motor? "I will be the beautiful phantom," she wrote to him, "glowing in color & eloquence, when you so order me." Or that Ivan Pavlov, the great Russian physiologist who sliced open countless dogs to see how their digestive systems worked, hated dissecting them and took pains to ensure they suffered as little as possible?

One of the scientists Johnson introduces did not shy away from painful experiments. Consider the bizarre procedure performed by Isaac Newton in his efforts to understand the nature of light. For the sake of science, he took a thin, blunt probe and inserted it "betwixt my eye & the bone." Newton faithfully recorded the results: "There appeared a greate broade blewish darke circle." Exactly what scientific conclusions Newton drew from stabbing his own eyeball is unclear, but his later, thankfully painless, work with prisms solved a problem that had vexed mankind for millennia. White light, Newton discovered, was not a single color but a mixture of all the colors in the spectrum.

But this book is about more than clever asides and scientific breakthroughs; it is about the experiments themselves. And that's where the going gets tough. Many of the experiments involved lengthy and difficult lab work. That kind of nitty-gritty research is tedious to do and even more tedious to describe. To maintain a narrative, the writer must omit some details, which can leave the reader with unanswered questions. For example, how could Antoine Lavoisier, the discoverer of oxygen, heat mercury one day to form mercuric oxide and then turn around the next day and heat the oxide to form the metal? And how did Albert Michaelson measure the small deflections of a light beam that led to his spectacularly accurate determination of the speed of light?

By carefully studying Johnson's accounts, one can usually figure out many of these experimental details, but picky readers (like me) will want to consult other references to fill in the remaining omissions. Those readers should not mind putting in the extra effort. After all, this is a book of popular science -- not a lab manual.

The experiment where many readers will need help is the story of Robert Millikan's Nobel Prize-winning work to determine the charge of an electron. "The technique," Johnson states accurately, "... was rife with uncertainty ..." It involved watching through a telescope as droplets of oil floated up and down in an electric field. "Hour after hour," Johnson writes, "he [Millikan] recorded the data, comparing the estimated weight of a drop with how much charge was required to keep it afloat."

This description is fine as far as it goes. But questions arise. For instance, how did the oil drops acquire a charge? (I found the answer on the Internet in less than a minute. Millikan used an atomizer to spray oil drops into the electric field. Some of the drops picked up an electron or two because of the friction between the oil and the atomizer's nozzle.)

To get a better feel for this difficult experiment, Johnson decided to replicate it. He painstakingly assembled equipment that was almost identical to that used by Millikan, and he began his observations just as Millikan had. However, his results were all over the map. Finally, he gave up. He realized what so many of us lab klutzes have discovered. Lab work is not just science, it is also art. Johnson nicely sums up his experience with Millikan's experiment: "for me to master so delicate an experiment would be like learning to play the violin ..."

This result leads Johnson to an important insight -- one known to almost every experimental scientist but rarely understood by those who work outside the lab. "These things sound so easy in the physics books," he writes wistfully. "You don't hear about the brass plates shorting out and sparking because a metal clip slipped into the wrong position. Or about spraying too much oil and clogging the pinhole." The knack for overcoming such small but annoying obstacles plays a big role in the making of an outstanding bench scientist. And scientists with that knack will continue to pursue difficult experiments because -- as this book illustrates -- that's where the scientific gold is.