Most Beautiful Experiment in Physics 141
An anonymous reader writes "Robert P. Crease has concluded his poll
asking what the most beautiful experiment in physics is. The winner was Young's double slit experiment performed using a single electron. Attentive readers will remember that Slashdot had a discussion of Crease's question previously, which Crease mentions in his current article." If you're unfamiliar with the experiment, Google pulls up a bunch of applets and demonstrations.
WOOHOO!!!! (Score:2, Interesting)
Why, I do believe that this is the first time I have ever been published. Thanks, guys!
Blockquoth PhysicsWeb:
My original article was also mentioned on Slashdot.org, an extremely active website. Although Slashdot bills itself as "news for nerds", its audience evidently includes a large number of science-history aficionados. A discussion with more than 500 comments ensued, many dissecting the merits of particular experiments. Here too the double-slit electron-interference experiment topped the list. One participant remarked that this and other experiments illustrating quantum-mechanical principles "even seem to reveal something about ourselves", noting that "philosophers and cranks are attracted to the results like moths".
Other Slashdot participants proposed many of the same experiments as Physics World readers - and often for similar reasons. However, they also came up with an imaginative variety of examples of deep play. These included fun things like putting discarded CDs into microwave ovens, firing potatoes using lengths of pipe and cans of hairspray, and synchronizing coloured lasers to the music of Pink Floyd.
One of the contributors described watching small plastic bags circulating in wind pockets, commenting that "sometimes there's so much beauty in the world, I just can't take it". Another mentioned the fact that a hunter firing at a falling monkey always hits the monkey no matter how far away it is, even though it drops just as the hunter fires. One person even cited sitting outside a hospital to hear the Doppler effect, with the comment: "Anytime an ambulance passes me, I'm amazed."
One Slashdot participant described a method of producing a fractal using a coin, marker and tape measure, claiming to have nearly cried the first time they saw it. Another described an impromptu game that he and classmates had invented at the end of a lab class, in which a liquid-nitrogen-filled styrofoam cup with holes in the bottom can be made to glide pleasingly around the floor when kicked about as the gas leaks out.
My favorite Physics Experiment (Score:3, Interesting)
For our experiment, we used a mirror set up to rotate at 6000 RPM. A laser is aimed at the rotating mirror, bounces about 20 meters across the room and back. The theory is that the rotating mirror will slightly rotate by the time the beam of light returns to the rotating mirror. Even at 6000 RPM, the mirror only rotates a very small amount, but enough for the laser's endpoint to change a few fractions of a mm.
By knowing the displacement between the endpoints of the laser at 6000 RPM and 3000 RPM, we could easily calculate the angle that the mirror rotated from the initial path to the return path across the room. Using this info, we solved for the time required for it to rotate that angle. That is the time required for the Laser to travel across the room and back. The distance:time ratio is the speed of light. Mad props to the dude/chick who designed that experiment.
I like the Pound-Rebka Experiment (Score:2, Interesting)
Pound is an interesting guy. He experimented with using microwaves to heat people instead of wasting energy heating entire buildings. He tested it out by rigging his microwave oven to operate with the door open. He told me that he had to bypass three interlocks, but that he got it working: there was a nice warm glow, like standing in front of a campfire.
Needless to say, don't try this at home unless you're a damn competent physicist.
Re:My favorite Physics Experiment (Score:2, Interesting)
He also demonstrated in Paris in 1851 that the earth did indeed revolve upon it's axis, by using a large pendulum. (Of course, people in 1851 had generally accepted that the earth did revolve around an axis, but this was the first physical demonstration of the effect of such rotation)
challenging our sense of reality (Score:2, Interesting)
Likewise, Michelson-Morley refuted the traditional hypothesis of the Ether(or aether). This concept was a kludge used to validate various assumptions. At that time, it was assumed that light needed a medium, and Ether was as good an explanation as any. By creating a beautiful experiment to refute the ether, Michelson-Morley forced scientist to study the problem instead of just making assumption. Progress is made when our fundamental assumption is proven false.
That does not mean that measuring physical constants is not beautiful experimentation. Certainly Foucault and Eratosthenes and Cavendish and even Milikan are great experiments which are instructive even now. But were they earth shattering pieces of experimentation. I do not know.
Most Beautiful Thought Experiment. (Score:2, Interesting)
Hacker types usually deride gedanken (thought) experiments as exemplified by Eric Raymond's idiotic Jargon file entry for 'gedanken'. So be warned: do not read ahead if you cannot appreciate the importance of theoretical work in physics or elsewhere.
Everyone knows the Schrodinger's cat and the Einstein's elevator experiment. By the way, if you put the Schrodinger's cat inside Einstein's elevator, would that lead to a theory of Quantum Gravity? Jokes apart, these thought experiments have also been influential:
1. The Einstein-Podolosky-Rosen or EPR Paradox: http://roxanne.roxanne.org/epr/einstein1.html
2. Maxwell's Demon
3. Object nearing a black hole
4. Feynman's QED thought experiment: what would happen when you shine light at an object passing through an interferometer, a device that can split the object into a pair of wavelets which are later recombined to produce an interference pattern. This incidentally was converted to a real experiment by an MIT team: http://www.aip.org/enews/physnews/1996/split/pnu2