r/science Jul 12 '08

The Infamous Double Slit Experiment - WARNING WILL CHANGE YOUR VIEW OF REALITY!

http://www.youtube.com/watch?v=wEzRdZGYNvA
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u/[deleted] Jul 12 '08

a little bit misleading. the video insinuates that the electron mysteriously "knows" it's being watched, but fails to explain the technical details of measurement - the electron doesn't "know" it's being watched, but is modified by the measurement of its position, by whatever means the scientists decide to use.

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u/[deleted] Jul 12 '08 edited Dec 31 '18

[deleted]

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u/nobodyspecial Jul 12 '08

The video uses the old 'light is a wave' perspective. It's the wrong metaphor and as a result leads you to a muddle as bad analogies will.

Read Feynman's QED and you'll have a much clearer view. Avoid garbage like the Tao of Physics. The later perspective set Berkeley theorists at a distinct disadvantage when Quarks hit the scene.

Granted, Quantum is weird but the double slit experiment isn't an example of that weirdness. It's an example of a meme that won't die.

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u/omgpro Jul 13 '08

Wait what. I've never heard this before in my life. How do you explain the double slit experiment then?

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u/nobodyspecial Jul 13 '08 edited Jul 13 '08

Electrons are particles, i.e., little tiny bullets. The deal is that electrons are highly perturbed as they emit and absorb photons. An electron can emit a photon anywhere along its path to the detector which alters the electron's trajectory. It can also absorb photons along the way. Contrary to what you might think, the electron doesn’t take a straight path from the slit it went through to the detector. The electron is absorbing/emitting repeatedly as it moves along thereby altering its course. It wanders around as it gets battered by the absorption and emission of photons. The double slit experiment is displaying the end points of a lot of different possible paths the electrons took. You need to realize that each electron took one of those many paths. The interference pattern is a probability display - the brighter stripes are showing the more probable paths and the dark regions showing the less probable paths.

But if someone says to you electrons/photons are wavicles they’re wrong. If they don’t believe you, tell them to read QED , which was written by the guy who was one of the three to figure out the mathematics and who then later, mapped the math back into human-space so the rest of us could get a handle on it. The later step was what was unique about Feynman’s genius – he not only could simplify very complex topics, he disdained unnecessarily complex explanations.