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Most Beautiful Experiment in Physics
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.
The beauty of this experiment is not just the effect that it generates but the way it simply demonstrates a complex phenomena. By complex I mean that it demonstrates that light travels as waves, until you fire only 1 photon then you prove it travels as particles as well.
Simple, brilliant and something that the more you learn about physics the more you learn about what the experiment shows.
An Eye for an Eye will make the whole world blind - Gandhi
the most beautiful experiment is, has been, and always will be the practical aspects of
* photons gets converted to electric impulses;
* these electric impulsese are stored, usually by dielectric tunneling, into a floating gate (Flash memory)
* the information is then read back, sent through 7 (read it, it's SEVEN) layers of network stack, to a physical link
* the data is digitized into more packets of light, and sent across the atlantic from RUSSIA to the US.
* after more routing (some in light-packets, some in electrical), it climbs back up the 7-layers.
* mozilla interprets them, and through some seriously complex transistor networks, the signals cause some polymers to twist just the right amount
* and i see some pr0n.
wait a sec; that would probabbly be "the most beautiful engineering feat"... ahh fsck it.
My life in the land of the rising sun.
My comment on the Slashdot thread made it into the article!
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.
Any demonstration that makes the lesson sink in to a student's head.
Kudos to one of my physics professors, Dr. Richard Mancuso, for his toy collection. Any student that brought him a toy that clearly demonstrated a principle of physics for that wasn't already in his collection got extra credit for the semester. I clearly remember the collection filling a few display cabinets, and there was at least one toy for every lecture. I learned 10 times more in his course than I did the previous semester with another instructor because he made it interesting.
Apparently not as fast as you are to condemn them, because they mentioned the previous slashdot article in this one.
Measuring the speed of light.
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.
No wonder this one won. ( wun wun? ) It is an elegant, easy to understand set-up with REALLY weird results. Something to smack your macro-world "common sense" upside the face.
"Like, huh? It's interfering with ITSELF? Like, is it a particle, or a wave, or what, teach?"
I think some of the crazy new laser "faster than light" experiments could probably give it a run for the money, but they are a lot harder to understand. There is nothing quite like the quantum world jumping up through your apparatus and presenting itself in all it's non-Newtonian glory.
I've got a bad attitude and karma to burn. Go ahead. Mod me down.
Comparing sound doesn't really help though.. that's a totally differnet thing. Totally different kind of wave in a totally different medium.. does the same thing even apply?
They dropped photons off the roof of a building and measured their blue shift at the bottom, confirming general relativity. One description of the experiement is here.
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.
Admit it, "PhysicsGenius". You call yourself a physics genius, but you probably watched "The Mechanical Universe" a few times on TV and maybe read Hawking's _A Brief History of Time_. You know as much physics as I do, and I failed Ph 2b at Caltech.
Experiments can be beautiful (although "elegant" is the description I prefer.) An elegant experiment has a certain simplicity to it, and a certain definitiveness to it which convinces everyone. Foucault's famous pendulum, for example--there are other ways to demonstrate the rotation of the earth, but Foucault was able to do so, graphically and undeniably, with a weight and a length of wire. Beautiful.
Or take the experiment which demonstrated that nucleic acids and not proteins carried genetic information. Hershey's and Chase's method was simplicity itself: proteins contains sulfur, and nucleic acids do not; proteins contain no phosphorus (or little of it), nucleic acids abound in it. So infect cells with a virus whose protein coat is labelled with radioactive sulfur, or whose nucleic acid payload is labelled with radioactive phosphorus, and see where the radioactivity ends up when cells are infected with the labelled viruses. The phosphorus gets transferred; the sulfur does not; hence it's the nucleic acid which carries the virus's genetic information. Again, beautiful.
If your view of science is really so crudely utilitarian, I suggest either that you get out of the profession, or (far more likely) you're not really a scientist at all but you've read about it in _Skeptical Inquirer_. Get back to your Linux installation, will you?
hyacinthus.
surely if the monkey is far enough away then the time that the light indicating the start of the fall takes to reach the hunter will cause him to miss high? it would also seem that the curvature of the earth would cause the hunter to aim low. surely these two effects don't cancel each other out completely?
Shroadinger's Peacock.
Table-ized A.I.
Beautiful as it may be with a single electron, or photon, or whatever. These have almost no mass. When done with buckeyballs, the double-slit experiment acquires an amazing beautyl.
We have an educable station that plays Mechanical Universe documentary lectures from the mid eighties. You can read more about those at:
http://www.themechanicaluniverse.com/
Highly recommended. The best demonstration I ever saw on that show involved three light polarizers. The setup was three polarizers on optical stands with a lamp shining through all three. That is, all three in the same orientation so the light shines through. The third is turned through 90 degrees and of course blocks the light of the lamp from the screen. Dr. Goodstein then turns the second middle filter through 45 degrees and almost half the light makes it through the screen. The result is completely counterintuitive and is an excellent and easy macro scale demonstration of quantum principles.
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.
"She's a scientist and a lesbian. She's not going to let it slide." Orphan Black
i always though the most beautiful experiment was creating kelly lebrock in wierd science!
chips, dips, chains, whips, sex, drugs, rock and roll... your average party.
There's nothing Intelligent about Intelligent Design.
How about a poll for the most beautiful or insightful thought experiment in physics?
5 3-2.htm
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
You forgot to mention.
The cool part of the experiment is when you start sending that light 1 photon at a time, so we can demonstrate that individual particles are being sent. The diffraction pattern STILL appears... so we end up with a particle interfering with itself.
Now, as people view light as some kind of weird beast.. the experiment is even more exotic when done with an electron beam. Done with single electrons, which we REALLY think of as particles, we still get the diffraction pattern. That's where things get really weird.