free range physics

Many of us take our public libraries for granted. It wasn't always the case. When I was a kid, the highlight of my week was when I'd accompany my mother to the local public library to check out a new selection of books. And when I was an impoverished student and young adult, the local library was the only way I could afford new reading material. But with financial stability came the wherewithal to actually buy books again, and libraries play a far lesser role in my life than in years past. Perhaps that could change, however. I have the good fortune to live just three blocks away from the Central Public Library in downtown Los Angeles: a lovely building with Schroedinger's equation carved into one of the stones gracing the steps outside, so really, how could I not be a fan? But it also has an active outreach program (volunteer tutoring) and regularly hosts taped "conversations" between authors in the Mark Taper Auditorium, free to the public as part of the ALOUD program.

I had the privilege of participating in one such "conversation" last week, hosting an evening with Richard Reeves, who just published A Force of Nature: The Frontier Genius of Ernest B. Rutherford. I was a bit outclassed, frankly: I'm a lowly science writer with a couple of pop culture physics books under my belt, whereas Reeves is former chief political correspondent for the New York Times with a list of honors and awards as long as my arm. His many books include a trilogy on modern American presidents: biographies of Kennedy, Nixon, and Reagan. Some might find it surprising to see Reeves turn his hand, then, to the biography of a venerable physicist, but it's less so if you know something of his background. He came of age during the Sputnik era, and graduated from Stevens Institute of Technology in New Jersey with a degree in mechanical engineering. So Reeves is no stranger to science.

That shows up immediately in his new book, which opens with a fascinating account of a recreation of Rutherford's pivotal scattering experiment in 1908. Reeves managed the feat with the help of a group of modern-day physicists at his alma mater, and I can't think of a better way to start such a book. After all, in a sense, this is well-traveled ground. While hardly a household name today (except in New Zealand, where he practically deified), Rutherford was once as famous as Albert Einstein, with the press reporting breathlessly on his latest research accomplishments. It helped that his research was literally earth-shattering: first he proved that the atom was not indivisible, then he won the race to "split" the atom, against teams with much bigger machinery and funds. Somewhere along the way he also won the Nobel Prize in Chemistry for his work on nuclear half-lives/radioactive decay. (There is more than a little irony in this, since Rutherford is also the person who famously observed, "All science is either physics or stamp collecting.")

Anyway, the scattering experiment is noteworthy because Rutherford noticed, a few years earlier, that a narrow beam of alpha particles became a bit "fuzzy" after passing through a sheet of mica -- a puzzling little anomaly, hardly worth noting, unless one happened to be a great physicist. "Rutherford was a great one for mulling over aberrations, anything out of the ordinary," Reeves writes. "That is where the secrets were, in the margins." So like all great scientists, Rutherford persisted. He set his assistant, Hans Geiger (inventor of the Geiger counter), the task of measuring the relative numbers of alpha particles according to scattering angle, and an undergraduate student, Ernest Marsden, got the thankless task of analyzing all the data to see if any alpha particles were reflected from metals. The answer turned out to be yes: in fact, some alpha rays were  scattered directly backwards from a thin film of gold, almost, said Rutherford, as if one had fired a large naval shell at a piece of tissue paper and it had bounced back. The only explanation of this result is that almost the entire mass of the atom is concentrated into a nucleus a thousand times smaller than the atom itself.

Fast forward not quite 100 years later, to November 5, 2005, when Reeves found himself  in a darkened laboratory in New Jersey, trying to get his eyes to adjust to the darkness so that when he looked through a microscope into the vacuum chamber he and his cohorts had constructed, he would see the telltale "scintillations": sparks of light, the result of alpha rays striking a phosphorescent wall after passing through a bit of gold foil.

It wasn't easy recreating the experiment. While vacuum technology had come a long way since Rutherford's time, it was also quite a bit more difficult to get hold of radioactive materials. Rutherford thought nothing of tossing bits of radium into his coat pocket, or depositing them into his desk drawer. (Apparently it cost $100,000 to decontaminate the famed physicist's desk before it was deemed safe for display. Yet Rutherford never showed any signs of radiation sickness in his lifetime.) Reeves' team had to use a distant descendant of radium, Americium-241, a significantly weaker source. Compare: the radon-222 used by Rutherford in his 1908  experiment produced 30 billion alpha particles per second, while the amercium-241 used by Reeves' team produced around 370 million particles per second. But they succeeded! Maybe they didn't recreate the experiment 100%, but they managed a solid 90%.

Based on the portrait that emerges in A Force of Nature, I suspect Rutherford would have approved of Reeves' willingness to roll up his sleeves and get his hands dirty with the real work of physics: cutting, sawing, soldering, and so forth. What I liked most about Reeves' biography is how it brought Rutherford the man to light: not just the scientist. He was quite the character, frankly. One of 12 children born to a New Zealand wheelwright/engineer (and later flax miller) and his schoolteacher wife, Rutherford showed early academic promise and eventually won a grant to study at the famed Cavendish Laboratory at Cambridge University in England. The lab's head, J.J. Thomson, took the promising young New Zealander under his wing and directed him away from his early research into radio waves and wireless transmission, into the nascent field of atomic physics.

It meant diverting the young man away from a path that would have made him extremely wealthy; Guglielmo Marconi eventually won the wireless race, and died a very rich man.  But Rutherford was an idealist at heart, and he followed his curiosity to investigate the nature of the most fundamental building blocks of nature instead: the structure of the atom. His scattering experiment proved once and for all that the atomic nucleus was not indivisible, and his model of the atom -- a tiny nucleus made of positively charged protons and neutral neutrons, around which orbited negatively charged electrons -- quickly supplanted Thomson's working "plum pudding" model. (You can build your own atom here.)

Rutherford was the last of the great "tabletop" experimentalists. Nowadays we have massive accelerators to smash particles into even tinier bits and pieces, at ever higher energies, but many of Rutherford's apparatus were no bigger than the proverbial bread box, and used such mundane items as string and sealing wax. All those years roughing it on New Zealand farms made Rutherford both thrifty and creative when it came to experimental materials. Reeves relates one anecdote of a young scientist under Rutherford who needed a bit of metal tube for an experiment; Rutherford had the young man saw off a piece of the handlebar of an old bike in the lab he'd kept around just in case the parts were needed.

Rutherford's early years at Cambridge were marred a bit by the snobbish elitism of some of his colleagues. After all, he was the first graduate student there who did not actually attend Cambridge as an undergraduate. He was also a bit rough around the edges: big, loud, boisterous, with a strong New Zealand accent. He was often mistaken for an Australian farmer, rather than one of the world's most prominent scientific minds. But he proved his mettle, again and again, and he judged people on their merits in turn. That included women and minorities: he admired and respected Marie Curie, for instance, and while he expressed surprise upon meeting Lise Meitner and finding she was a woman, the fact of her gender did not diminish her scientific achievements in his eyes. Nor was Rutherford especially political. Alas, he had the misfortune to live through the onset of two world wars, losing more than one promising young scientist to the trenches. With the ascension of Hitler and the ousting of Jewish scientists in the 1930s, Rutherford pulled every string he could manage to find places for his former Jewish colleagues. So he was simultaneously a man of his era, and rather enlightened for that day. Some 13 of his former students went on to win Nobel Prizes of their own, so he left an indelible mark on physics beyond the narrow confines of his own research.

One of the more surprising aspects of Reeves' biography is the figure of Rutherford's wife, Mary, a strict religious woman with a sharp tongue who did not hesitate to cut her husband down to size; nor did she mellow with age. She seems to have been the antithesis of her boisterous, gregarious husband. The couple had one daughter, Eileen, who died giving birth to her fourth child. Reeves is not the first to speculate that Rutherford's fond, paternal attitude towards the "boys" in his lab might be indicative of his longing for the son he never had. Lady Rutherford also managed to squelch many of the details surrounding Rutherford's death in 1937 for many years. Rutherford fell while trimming a tree in the yard, and apparently she tried a homeopathic "healing touch" attempt at a cure before calling in a doctor -- at which point it was too late. The great man succumbed to the ignominy of a partially strangulated umbilical hernia, and was buried in Westminster Abbey. His estate: around 7000 pounds, pretty much the amount he'd received for his Nobel Prize. But his place in physics history is rich, indeed.

There's a lot more color and detailed anecdotes in the actual book, which I encourage folks to read on their own. As we were winding things up after last week's conversation, Reeves expressed his surprise and gratitude at the number of people willing to trek to downtown LA on a weeknight to hear about a not-so-well-known (in this country) physicist. I was surprised, too, although I suspect many of the folks who came were there because of Reeves himself -- a writer of no small stature. My favorite moment of the evening occurred when someone asked him if there were similarities between his past presidential biographies and this most recent scientific one. While conceding that Rutherford shared a larger-than-life persona and gift for inspiring others with Presidents Kennedy and Reagan, Reeves said bluntly, "Presidents are pygmies" in comparison to the great men of science -- not meant in any way to disparage the achievements of political leaders, mind you, merely to put those things in true perspective.

Comments

[Lab Lemming]

I've always wondered why the guy who put the "nuclear" into physics never won the Nobel prize.

[Tom Levenson]

Actually, to torque Reeves a bit, we probably want presidents to be pygmies as compared with the great scientists. The "Man on the White Horse" -- the great leader -- is a very dangerous kind of person to put in charge of a three trillion dollar budget and all the state powers available to the man or woman (we'll see...) resident at 1600 Pennsylvania Ave. The job of a President is rather to find ways for people much more capable than him or her at any particular task to do their jobs well -- and feed the good stuff into the intense constraint of one brain trying to shape directions for that enormous machine. We've seen what happens over the last few years when the pygmy model gets rejected: intuition and shots from the hip replace real leadership.

It's a very tricky skill to be both in charge and able to make sure that the people you need to do well will do so; and it is very different from the kind of capacities for which we rightly reverence an Einstein or a Rutherford. It has also, sadly, been an increasingly distant memory for a while 'round these parts.

[Joerg]

I'm even more in awe about the Millikan experiment, where via a microscope, he adjusted an electrical field so that really small droplets of oil sprayed into a chamber would float - meaning that the electrical and gravitational field forces balanced out. This way he determined the elemental charge e. But just image staring at small droplets for weeks at a time...
The worst experiment I had to do was the Michelson interferometer, where you had to count lines through a small lens, by turning a small wheel. You had to count 100 lines, but even a person moving outside the room would cause them to jump around...

[CCPhysicist]

Should be an interesting book.

I heard a colloquium by a retired professor who had been a post doc with Rutherford at the Cavendish and worked on similar experiments.

1) The source they used was preposterously radioactive by today's standards, even if you are a radiation worker wearing a dosimeter etc rather than the random journalist doing an experiment. The people doing the measurement work would go in a small broom closet to remain dark adapted while an assistant did any adjustments to the equipment or brought in a new source. The source itself was bright enough (from causing scintillations in the air) to ruin your night vision.

1a) They smoked their pipes in the closet with their eyes closed to stay dark adapted. Radiation wasn't the only pollutant they were exposed to.

1b) When asked about radiation hazards, he said Rutherford told them to get plenty of fresh country air when not in the lab.

2) If you have never done an experiment like this (say optical spectroscopy), you might not realize it takes at least a half hour or more to become dark adapted, and that the room needs to be totally dark. Even then, he said they needed several observers to take turns counting because you start to see things after concentrating for more than 10 or 15 minutes through the microscope. It is little wonder that Geiger invented an electronic counter!

[michael cassidy]

reeves is still kicking.

i worked with him at nytimes; i was a copyboy he a reporter, so he'd never remember.
he was a good writer; i assume he is still, so i will buy the book