Intro to Polarization Filters! or...why are those sunglasses so expensive? | Doc Physics
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- Опубликовано: 19 фев 2013
- We figure out why light waves that are shaking a certain direction can make it through polarization filters while others can't. We also hint at the Law of Malus and more beautiful Polaroid filter combinations.
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FINALLY SOME ONE WHO CAN ACTUALLY EXPLAIN PHYSICS WITHOUT MAKING IT BORING! Physics is probably the most interesting subject - yet every where I look people have managed to make it such an unfriendly topic! Thank you so much :D
You are quite welcome. I love physics, too!
Well done brother.I am Physics student and i had a project in polarization weeks ago and you refreshed my knowledge there.
Hands down the best demonstration I've seen on this topic. Thank you :)
I'm dodgy because I'm not an expert. You'll want an engineer for that question, since I believe it is a standard analysis technique for stress and strain in materials. I'd love to hear what you learn! Thanks for watching!
Mariam - I am sorry to confuse you! I elected to only draw and discuss the electric field. But you are correct. The magnetic field is destroyed simultaneously when the electric field is. The light as a whole is absorbed.
There was a day when polarized lenses were GREAT, and then came the era of LCD screens. I got real tired of twisting my neck this way or that to be able to see what was on an LCD screen. My scrip is so ugly that it takes much effort, these days, to actually find a place that can make me sunglasses without that polarizing stuff being included.
THANK YOU... I have another question. What if we replace that polarising filter with a metal ( like iron ) grill, then will the metal grill get itself magnitised by the effect of the electric field or will the WHOLE light gets kinda absorbed and dies eventually and so does the magnetic field? ... where does the magnetic field go? I watched the "Polarisation video" like more than once , it makes perfect sense to talk about the electric, but then why doesn't the magnetic field show any effect in this case ?
I'll have to defer to someone who knows more about polarization of light. That's an interesting question.
+Live Free The electric field energy excites the electrons of the material you are using. The electrons then de-excite and give out light in a plane perpendicular to the plane of polarization
but, don't the two fields give rise to each other? if the magnetic field is gone, how is there an electric field?
Those experiments were AMAZING!!! Funny how we could see through!!
Doc you are the boss !!! All teachers/lecturers should be like you to make this world a better place. With lecturers like you around everybody could easily become a quantum physicist. In short ,we desperately need to clone you !!!
Alternation is a very common mistake. I also thought they alternated once, but they don't. There is an oscillation, so at any given time, the wave is either E and M (normal to each other) or NOTHING AT ALL. The same argument applies for various locations in space for a continuous traveling wave. So you can only block both or none. There is no try.
Those are great ideas. I'll put them on my short list! Thanks for your interest.
This is hilarious and so helpful. Thanks a million :D
doc you are so close to answering my lab question for me
Honestly you made this so much easier to understand! Thanks so much!
Absolutely amazing!
Keep up the good work!
Thank you. I have been reading and watching many videos on this, and finally YOURS explains it! :)
I really love the way you explained it.You sir are a great teacher.
Your enthusiasm is infectious. XD Thanks for the video.
By the way. The light waves has a hight, right? What scale are we talking? And does it vary?
Thanks.
That's consistent with what wrobert3 writes, but is it simply absorption and isotropic re-emission of the light or is it turning into heat. I'm no chemist.
your excitement is so passionate I love it
I got a crystal clear idea of polarization of light. Thank you so much ^_^
Doc you r awsm buddy. Best physics instructor
Yes! So there is some sort of "molecular friction" along the molecule's long axis that converts the oscillating E field to heat? Thank you - I was hoping to understand that!
I usually model this in class with the slats on a baby crib. Thanks for enriching me.
You are so quick, very nice doc master physics
Omg. that was the first time I ever said "That was AWESOME" and smiled while learning smtg about physics. you sir, gave me all the motivation I need to do well on my exams. Thank you.
THANK YOU!
Fun question! Since E =cB always for light, when E decreases, B also does proportionally. Targeting one or the other would be impossible, as far as I can tell! Short-sighted physicists are always getting in trouble by saying things are impossible, but I'll risk it.
Yes! Thank you.
just an enormous thank you!! really helpful!
Great video ..Awesome explanation. Thanks!!!!!!
Surprising, to say the least. It naturally falls out of the vector decomposition, but it makes you think about stuff differently. Did they tell you that you can sail into the wind, also? Think about your question as you begin to study quantum physics, too. The middle filter can be seen as an "observer."
Wow! A very cool video! I have an exam on polarization tomorrow, this video really helped, thanks!
P.s loveee your enthusiasem
Excellent videos. Keep up the good work!
See, I used to feel that way, also. But can we view them as transforming INTO each other if they both reach maxima at the same time and location, then both reach zero together at a later time, etc? Both oscillating, to be sure. Transforming? I am no longer sure.
Thanks. Lucid explanation.
I think so. Or put it like this: The only E field that can make it through a polarization filter is the component of the original field that is parallel to the axis of the filter. If a subsequent filter is pi/2 from the first one, it will not allow ANY light from the original filter to pass. Cool. However, since light from, e.g., an incandescent is unpolarized, when it reaches through a p-filter, exactly half makes it through. Ready for the lab?
its really a great way to make that stuff easy..........thanks a lot.
Actually, magnetic fields pass through each other completely undeflected. May I recommend my videos on wave interference?
Sir that was an awesome video u made.............thnkx
awesome explanation! Thanks :)
This is the best video on this very topic I like it more than any one
I'm not a physics guy but the way I see it... the middle filter picks up light at a certain angle from the bottom one, which makes the one on top see it at this new angle that the middle one is outputting at. Like standing 10 feet away from your bedroom door in the hall where you cannot see inside your bedroom. The someone holds a mirror in front of the open door pointing it between the room and you down the hall. Now you can see inside the bedroom. Turn mirror slightly and you see less in there
Hi, Thanks great video! Just a note. The molecules in the filter are parallel to the E-field when the light gets absorbed and perpendicular when they are transmitted. The parallel electric field can do work and move the electrons along the long molecules transferring energy (resulting in absorption). The transmission axis is at 90 degrees to the long axis of the molecules.
Finally! I don't get why all these darn "physicists" don't just explain things clearly like in this video. Thank you!
Helpful. Thanks!
brilliant vid!
Ooh, good thought. Light requires the relationship E = cB, so Maxwell's equations will guarantee that B is decreased proportionally to E. I can't quite motivate why though...anyone else know a good reason?
really good video!!! would you please help by making a video on polarisation of sun glasses
Schuster thnks and keep uploading videos like that
thanks Doc
man u r tooo good pls upload some more videos!
i have a question why light has magnetic field and if it has the light should travel more towards magnet right?
Great video!
That was Terrific
Loved it Doc
Newton's cool tho😂😂
Thank you so much!
thank you, very helpful
You are completely amazing
i love you man! you remind me of Dory in finding nemo!
great video, thank you!
This video is great. I know i can always count on him.
Shoot. Now you're convincing me that both could be equivalently argued to being blocked. Changing H field will exert force on the electrons in those long organic molecules in just the same way as the E field (but at a right angle). So, I think the key is to see light as a necessary simultaneous combination of oscillating E and H fields. They BOTH interact with the nonconservative forces in the organic molecules.
SQUURRRR
I love this guy
Wow. Just wow.
Off the wall inquiry, is there a way to view wifi or wave lengths through some form of Polarized optic?
thank you very much :)
Hi Doc! Can u please help me understanding process of polarization by reflection, scattering and refraction? please!
Our teachers decided not too teach us anything on this even though it's a large part of my as levels, thanks for explaining it.
Nice tutors😁
Thank you very much ! You make my life easier. :))))
Ooh!! It's a nice teach Mr doc phys 😘
Alright! Get 'em!
omg, thank you very much you saved my life because I have a test tomorrow thank you.
This will help my photography :-)
can be used CPL filter like not so good but some protection camera vs lasers ? :)
cool stuff...is it possible to isolate or amplify only the magnetic wave
No: E = cB is necessary for light to exist, and it comes from Maxwell's wave equations.
Hi,
In the video, you said a polarization filter works through molecules lined up that blocks the electric or magnetic field or both depending on its angle. However, how does this block out light? Would't diffraction occur even if the spacing between the organic molecules of the polarization filter were really small?
Thank you in advance for all who take the time to answer my question.
GREAT VIDEO .....such an inspiration !! I wish you were my tutor in the other side of the world !
I only find myself confused about the diagram you drew of the electric field WITHOUT the magnetic field ...In EM Waves video , you have mentioned that electric fields cannot exist without a magnetic field ...so why did you just cancel it it it were to exist and have an effect ?
Perfect
Isnt the plastic slowing down the electromagnetic wave, and thereby the frequency ?
so does this mean that to block out all light, the magnetic and electric fields must be at right angles to two different filters?
good job
Sir, you are Awesome!
Thanks, Rham! I think you're great, too!
Doc Schuster lmao coolest teacher ever :)
Tqsm sir
First off, this is an amazing video, congrats on making it! Secondly, I wish you would have been a tad more blatantly explicit when explaining how putting certain materials between two polarizers creates the colors. What determines the colors you see in the material?
you're just so great
The best!
HEY THANK YOU...... I ENJOYED THE VIDEO
GOOD......
The light coming from first polarizer sheet is polarized and the change in intensity of transmitted light through 2 polarizer is the proof .
Unpolarized light will never show change in intensity when passed through the polarizer sheet , the electric filed randomly changes direction at all instants so the polarizer sheet is working at all angles .
I heard him saying light coming from 1 polariser sheet is unpolarized !
Correct me if I am wrong here .
6:04 wowooowowowoow "That's some beautiful physics"
Nice
why can i see the object when it was placed between the the filters??can someone explain please??
After the introduction of the 1st polarizer what happens to the magnetic field? Does it get absorbed or it passes through with the electric field.
+Adhish Rele We know that E = cB for light, so as E is absorbed, so is B.
I can't understant why if we have two polarized filter at a right angle and we put another one between the two at an angle of, let say 45 degres, we will see light back ?
ya offcourse!thanks.
Out of curiousity, how to tell that it is the E field got blocked and not the H field got blocked ? thx
How does plastics reverse the effect of polarization?
oh, i think I misunderstood you. True, their intensity ratio is constant.
I think of transformations because their changes generate each other.
thx
well, you mean maximum energy? If so, there would be no energy conservation I guess (E*H must be const). They need to replace each other when moving.
hi, love the video but id like to suggest a small correction but please correct me if I'm wrong. in the beginning you mentioned the hydro carbon molecules in the filters and drew them in the same direction, parallel, to the axis of polarization. It is my understanding that the organic strains are stretched perpendicular to the axis of polarization and while this isn't ideal for visual representation it contradicts the science behind why the molecules are filtering only certain electric waves. The easiest path for electrons to travel in these filters is along the strains which is how the waves are being absorbed, or maybe dampened would be a better term, and therefore the waves perpendicular to the long strains of organic molecules are the ones that actually make it through. I am researching polarization for a college presentation so any correction in my thinking would be appreciated if i am wrong.
I lv ur physics
I found an interesting property of polarizing filters, Infrared light can pass through them, At least from what I've seen,