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Young's double-slit experiment applied to the interference of single electrons

Neither Newton nor Young was quite right about the nature of light. Though it is not simply made of particles, neither can it be described purely as a wave. In the first five years of the 20th century, Max Planck and then Albert Einstein showed, respectively, that light is emitted and absorbed in packets -- called photons. But other experiments continued to verify that light is also wavelike.

It took quantum theory, developed over the next few decades, to reconcile how both ideas could be true: photons and other subatomic particles -- electrons, protons, and so forth -- exhibit two complementary qualities; they are, as one physicist put it, ''wavicles.''

To explain the idea, to others and themselves, physicists often used a thought experiment, in which Young's double-slit demonstration is repeated with a beam of electrons instead of light. Obeying the laws of quantum mechanics, the stream of particles would split in two, and the smaller streams would interfere with each other, leaving the same kind of light- and dark-striped pattern as was cast by light. Particles would act like waves.

According to an accompanying article in Physics Today, by the magazine's editor, Peter Rodgers, it wasn't until 1961 that someone (Claus Jönsson of Tübingen) carried out the experiment in the real world.

By that time no one was really surprised by the outcome, and the report, like most, was absorbed anonymously into science. (Ranking: 1,)

Whether they are blasting apart subatomic particles in accelerators, sequencing the genome or analyzing the wobble of a distant star, the experiments that grab the world's attention often cost millions of dollars to execute and produce torrents of data to be processed over months by supercomputers. Some research groups have grown to the size of small companies.

But ultimately science comes down to the individual mind grappling with something mysterious. When Robert P. Crease, a member of the philosophy department at the State University of New York at Stony Brook and the historian at Brookhaven National Laboratory, recently asked physicists to nominate the most beautiful experiment of all time, the 10 winners were largely solo performances, involving at most a few assistants. Most of the experiments -- which are listed in this month's Physics World -- took place on tabletops and none required more computational power than that of a slide rule or calculator.

What they have in common is that they epitomize the elusive quality scientists call beauty. This is beauty in the classical sense: the logical simplicity of the apparatus, like the logical simplicity of the analysis, seems as inevitable and pure as the lines of a Greek monument. Confusion and ambiguity are momentarily swept aside, and something new about nature becomes clear.

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The topic that you gave us about the eleven most beautiful experiments in the world was so interesting, that it compelled me to try even harder to find out more about some of the experiments that I had come across. Talking about experiments, i came across this quote by Albert Einstein which I would like to share:"A theory is something nobody believes, except the person who made it. An experiment is something everybody believes, except the person who made it."

What is a beautiful experiment? In the eye of a scientist, beauty lies in the simplicity and ingenuity of the design, and the unambiguous result that opens a new world of understanding. This topic was quite intriguing and doing a project on the 11 most beautiful experiments was certainly a wonderful experience .

So True Amatullah. I completely agree with what you have written.

this project of making a video on 11 most beautiful experimnents was an amazing idea.
i really enjopyed making it.

I totally agree with both of you!!
It was truly a enjoyable experience.

Yep! The best part was doing the research. We came across such beautiful experiments while doing the research!

I know, I didn't even know about the gummy bear and potassium chlorate experiment. Just saw it on youtube, its fantastic

Yeah! Afterall it was my recommendation! And yeah I heard that principal behind the gummy bear experiment is the one used in fireworks!

I have prepared a documentry on Galileo's experiment of the inclined planes. I gained a lot of information about the theory of time and speed during the research and have also improved my IT, skimming and scanning and my writing skills. It was an amazing opportunity and we all have taken good benefit from it. Thank you ma'am. "All truths are easy to understand once they are discovered; the point is to discover them." Galileo Galilei.

While researching I also came across this interesting experiment by Ernest Rutherford when he discovered the nucleus in an atom. Long ago atoms were generally believed to consist of large mushy blobs of positive electrical charge with electrons embedded inside them. So to find out more about an atom, Rutherford and his assistants fired tiny alpha particles(positively charged particles), at a thin foil of gold, and were surprised that a tiny percentage of them came bouncing back. Rutherford came to a conclusion that the core of an atom was made out of positive particles named protons and neutral particles named neutrons found inside a nucleus, which was the reason why some of the alpha particles bounced back. I think this experiment is definitely worth a look.

Galileo staring down gravity, Newton breaking apart light, and Pavlov studying his now famous dogs..........I'm reliving those good old school/university days, when I used to be pouring down those gigantic books in the library, digesting the work of these great scientists.

Have you heard about Demetrius, a greek philosopher and up on him and put in your comments.

I loved the idea about reseraching on the most beautiful experiment it was mesmerizing and after looking through a lot of experiments i came onto the experiment performed by Sir Isaac Newton, "What a colour is?" where he disperses light into a spectrum of seven vibrant colours and in my opinion it is the most beautiful experiment.



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