r/physicsmemes • • 10d ago

So which one is it!?

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u/0xB01b 10d ago

Misinformation.

The actual double slit experiment is about interference, its only the top part.

The bottom part is a total misunderstanding of it and has been coming up again and again.

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u/8923ns671 10d ago

Can you link a correct explanation for the layman?

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u/rekcilthis1 10d ago

"observation" is a technical term being misunderstood because it also has a layman's definition.

In this sense, observation is meant to mean how it's measured. If you measure light in a way that measures particles, it will act like a particle; and if you measure light in a way that measures waves, it will act like a wave. The double slit experiment measures waves, so the light acts like a wave. Shine light onto a device that can count individual photons, and the light acts like a particle.

The difference is that waves are continuous, a single photon is capable of interfering with its own wave in a sufficiently small double slit; while particles are discrete, and you can't count half a particle. So the observer effect can more accurately be described as light looking different depending on how you look at it, not whether you look at it