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The Most Beautiful Experiments in Physics
TheMatt writes "In this month's 'Physics World', Robert P. Crease asks the question: what is
the most beautiful experiment in physics?
Some criteria quoted are that it must change what people thought, must not be too complicated or expensive, and, most importantly, be within the reach of students (which leaves out Stern-Gerlach or Michelson-Morley). He also has a page at BNL reprinting the article, with a
place for suggestions from the community on their opinion." I'll nominate a simple one: Foucault's Pendulum. :)
I like the idea of exploring colored lasers.. especially synched up to Pink Floyd music ;)
Moderation: Put your hand inside the puppet head!
The two slit experiments are the most beautiful. With a simple apparatus it can be shown that light is a wave. With the same apparatus, it can be shown tha light is a particle. And that's not all folks...
The experiment reveals that there's something very very weird happening with very small particles. It could be another universe, or maybe an infinite number of universes. Or maybe just one really weird one. Time itself doesn't seem to have any meaning - things happen for no reason at all, uncaused.
These experiments even seem to reveal something about ourselves. Philosophers and cranks are attracted to the results like moths, offering their own explanations for what is happening, ranging from the hand of god to the basis of intelligence.
The strangeness revealed by the two slit experiment could also form the basis of future computers, where all calculations happen at the same time, but you can't look at the result without destroying the entire computer.
If that whole mess isn't beautiful, I don't know what is.
If tits were wings it'd be flying around.
In this experiment, tiny drops of oil are suspended in mid-air between two charged plates by the interaction of a discrete electric charge on the oil drop.
You use a microscope to measure the speed of the drop with no charge on the plates, then adjust the charge on the plates to hold the drop in place. In other words, the force of gravity is cancelled by the electrostatic force.
If the drops are small enough, you can notice discrete steps in the data when you plot the variables. The beauty is in its simplicity: Using some oil, two pieces of metal and microscope, you can determing the charge of a single electron.
It doesn't get much prettier than that.
Muerte
The Pitch Drop Experiment.
If you check the site out, you will even find a live RealVideo stream of the pitch.
Pitch (a derivative of tar once used for waterproofing boats) feels solid at room temperature, and it can easily be shattered with a blow from a hammer. However, at room temperature it is actually fluid.
Quoting from the website:
"In 1927 Professor Parnell heated a sample of pitch and poured it into glass funnel with a sealed stem. Three years were allowed for the pitch to settle, and in 1930 the sealed stem was cut. From that date on the pitch has slowly dripped out of the funnel - so slowly that now, 72 years later, the eighth drop is only just about to fall."
What were the skies like when you were young?
The best experiment is really a pair of them: Young's double slit experiment, and the photoelectric effect. Young's double slit experiment showed that light acted as a wave. The photo-electric effect showed that light acted as a particle. Together they showed that light acts completely unlike anything we experience in the classical world.
Both are simple, easily doable in the laboratory for undergraduates, and after doing (and comprehending) both you'll never again think the same way about light.
Eratosthenes accurately estimated the diameter and circumference of the earth with a stick. That's beauty.
Actually, this exact question was asked at an Olympics of the Mind competition back in 1990 or so. Teams had to submit as many creative answers as they could.
Answers were fantastic, far more creative than this one, included, but not limited to:
Accellerate the building towards c until it appears the same size as the baromoeter, and use the resulting speed to calculate the original size.
Drop it off, and observe the impact damage it makes to the ground. calculate the forces needed to do this.
Run far away from the building and hold the barometer at arm's lentgh until it appears the same size as the building. DO some trig.
Drop the barometer, and listen for the delay betwen it hitting the ground and the sound reaching you. Calculate height based on speed of sound.
ANd I really wish I could remember some of hte other 50-odd answers that one team came up with... it was fantastic.
And I think the thing about Bohr is an urban legend.
How about superfuidity?
Seriously, that is one of the coolest and creepiest things at the same time, watching liquid helium crawl UP and spill out of a container. Granted liquid helium is rather expensive it is something which should really get the little buggers thinking and doing some research.
--Won't that be grand? Computers and the programs will start thinking and the people will stop. - Dr. Walter Gibbs