Why do these polarizers polarizers pass light through when stacked, even though each one individually blocks it? (photos.aesistril.com)

submitted 3 weeks ago* (last edited 3 weeks ago) by yogurtwrong@lemmy.world to c/askscience@lemmy.world

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[-] NoSpotOfGround@lemmy.world 1 points 3 weeks ago* (last edited 3 weeks ago)

Apparently it's due to the wave nature of light, and proves that photons are not "just" particles. You have three polarizers there: two in your hand and one in the screen.

This link explains it: https://alienryderflex.com/polarizer/

In brief, light oscillates transversally to its motion and a polarizer lets through the component of the oscillation that projects onto the polarizer's allowed direction. If you have two filters at 90° you get 0% transmission, but if you have an intermediate step, 90° to 45° is 70% transmission, and 45° to 0° is now 50% final transmission. Because light is sometimes analog.

[-] Blue_Morpho@lemmy.world 0 points 3 weeks ago* (last edited 3 weeks ago)

and proves that photons are not "just" particles.

Not really. Treating photons as waves is a mathematical shortcut for calculating some problems.

The more accurate way is to treat photons as particles with a probability amplitude.

"I want to emphasize that light comes in this form-particles. It is very important to know that light behaves like particles, especially for those of you who have gone to school, where you were probably told something about light behaving like waves. I'm telling you the way it does behave- like particles."

Feynman QED.

[-] NoSpotOfGround@lemmy.world 0 points 3 weeks ago

“If I say they behave like particles I give the wrong impression; also if I say they behave like waves. They behave in their own inimitable way, which technically could be called a quantum mechanical way. They behave in a way that is like nothing that you have seen before. Your experience with things that you have seen before is incomplete. The behavior of things on a very tiny scale is simply different. An atom does not behave like a weight hanging on a spring and oscillating. Nor does it behave like a miniature representation of the solar system with little planets going around in orbits. Nor does it appear to be somewhat like a cloud or fog of some sort surrounding the nucleus. It behaves like nothing you have seen before.”

Also Richard P Feynman.

[-] Blue_Morpho@lemmy.world 1 points 3 weeks ago* (last edited 3 weeks ago)

The difference is that quote is from 20 years before he wrote the book QED. The book QED explains Quantum Electrodynamics from the standpoint of particles. Quantum Electro Dynamics, which Feynman was fond of reminding everyone was the most thoroughly test theory ever (QED theory matches experiments more so than even General Relativity), is based on treating light as a particle with a probability amplitude.

Whereas there is no way to explain experiments if you assume a photon is a wave because there is no continuous reduction in detection. Observations are ALWAYS discrete.

So on the one hand you can have a theory that treats photons as particles with a probability amplitude, and it explains every observation. On the other hand, you can treat a photon as a wave and then have to handwave away observation by claiming the photon is a wave until observed at which point it instantly transforms into a particle through an unobservable process.

The math works either way, but Occam's Razor is a good principle where when you have two theories and one has extra unobservable processes, the simpler theory is more likely to be the correct theory.

[-] roofuskit@lemmy.world 0 points 3 weeks ago* (last edited 3 weeks ago)

Polarizers don't block light, they polarize it.

https://en.wikipedia.org/wiki/Polarization_(waves)

Read under Applications and Examples.

They block it when they are not aligned the same way, they pass or through when aligned.

[-] altphoto@lemmy.today 1 points 3 weeks ago

Totally agree with your new science. Polarizers don't block light, they polarize it. That's why when you shoot a high power laser with unpolarized light the filter gets hot. Obviously what is happening is little tiny monkeys glued to the surface of the optics, they catch the waves that are coming in the wrong direction and they manhandle those rays to their will so that all the light that passes is only in one direction or in the cyclical direction.

Simple. And monkeys sweat so that's why the glass gets hot. Some times if you shoot too much energy you'll make the monkeys melt the glass in sweat.

this post was submitted on 03 May 2026

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