If this wasn't a science page, if this happened 3,000 years ago in, say, a Middle Eastern desert, I would call it a Miracle. But it's not. It's just a plain, ordinary moment of "wow!"
First, the beginner's version. A man takes a bunch of metronomes, sets them ticking in different ways, then — and this is the crucial part —he lifts them collectively off the table, so their different motions now start to offset each other. And this happens:
But why? How does it work, you may be asking. I wondered too, and simply stated, what we have here is the transfer of momentum resulting in the alignment of motion. (Don't be afraid. Keep reading.)
Even more simply stated: As the metronomes tick back and forth, they affect the table, and because the table is designed to absorb the motion of the metronomes, the table itself starts to move. Now that the table is rocking ever so slightly, it begins to affect the metronomes on top. Metronomes that are moving with the table keep doing that. Metronomes not in sync with the table have their motions dampened, then countered, until they do it "the table's way." Eventually all the metronomes come into alignment.
That's what you saw in our small, chamber music version. Now we're going symphonic.
This time, we'll have a much bigger table with 32 brightly colored metronomes — a Mormon Tabernacle Choir of metronomes — all misaligned. It will take two minutes for most of them to fall into line. But there's one gloriously stubborn metronome in the second row on the extreme right that fights the mob and won't conform. In fact, it cleverly chooses to follow the beat but in exactly the wrong direction. I thought maybe it would be allowed to stay that way, a Minority Of One ... persisting against the tide, but ... well ... you'll see ...
They once made a movie about that stubborn metronome. It was called One Flew Over the Cuckoo's Nest, and the metronome was played by Jack Nicholson.
Robert Krulwich is co-host of Radiolab, WNYC's Peabody Award-winning program that examines big questions in science, philosophy and the human experience through compelling storytelling. Today, Radiolab is one of public radio's most popular shows. Its podcasts are downloaded over 4 million times each month and the program is carried on 437 stations across the nation. In addition to Radiolab, Krulwich reports for National Public Radio. “Krulwich Wonders” is his NPR blog featuring drawings, cartoons and videos that illustrate hard-to-see concepts in science.