george_johnson's picture
Author; The Cancer Chronicles, The Ten Most Beautiful Experiments; Columnist, The New York Times
Science writer; Author, Miss Leavitt's Stars

I used to think that the most fascinating thing about physics was theory — and that the best was still to come. But as physics has grown vanishingly abstract I've been drawn in the opposite direction, to the great experiments of the past.

First I determined to show myself that electrons really exist. Firing up a beautiful old apparatus I found on eBay — a bulbous vacuum tube big as a melon mounted between two coils — I replayed J. J. Thomson's famous experiment of 1897 in which he measured the charge-to-mass ratio of an electron beam. It was thrilling to see the bluish-green cathode ray dive into a circle as I energized the electromagnets. Even better, when I measured the curve and plugged all the numbers into Thomson's equation, my answer was off by only a factor of two. Pretty good for a journalist. I had less success with the stubborn Millikan oil-drop experiment. Mastering it, I concluded, would be like learning to play the violin.

Electricity in the raw is as mysterious as superstrings. I turn down the lights and make my Geissler tubes glow with the touch of a high-voltage wand energized by a brass-and-mahogany Ruhmkorff coil. I coax the ectoplasmic rays in my de la Rive tube to rotate around a magnetized pole.

Maybe in a year or two, the Large Hadron Collider will make this century's physics interesting again. Meanwhile, as soon as I find a nice spinthariscope, I'm ready to go nuclear.