How to Make Teaching Come Alive - Walter Lewin - June 24, 1997

Talk given by Prof. Lewin almost every year between 1996 and 2004 during the summer vacation for Science Teachers. This recording is from 1997. He discussed how to uncover the beauty of physics to students. He discusses the perception of seeing color and showed colors by using only black and white slides (the famous Edwin Land demo). He also covered (and demonstrated) Rayleigh Scattering which makes the sky blue and sunsets red. By holding cigaret smoke in his lungs he demonstrated why clouds are white.He uncovers the Physics of Rainbows and creates a rainbow during his lectures and he demonstrates (as he earlier arrived) that the rainbows are nearly 100% linearly polarized.

[@thesafteycrazycuber]

I found your lectures about two years ago sir Lewin and I must say I adore them so numerous and easy lectures to understand

[@lecturesbywalterlewin.they9259]

SUPER

[@arunkrsingh1328]

yes

[@automators]

Leuk om weer te zien.

[@fireballdude7368]

Professor*

[@davidbrayton1143]

If they handed out Oscars for physics lectures, he’d win another one for that lecture. Really, a phenomenal presentation in every way. He’d probably win a technical achievement award too for that magic chalk.

[@Ryzen_56X]

In high school I was a very bad student, I had to take night school to graduate, for some reason I did not find academic knowledge or school interesting or amusing at that time .... years have past for me and I found out the reason of my poor academic performance at that time, the school method of teaching lacked creativity to reach and awake my interest towards it. I discovered your videos at the beginning of this year and got hooked up immediately with them ... guess what ? I started college this fall in Aerospace engineering because I find your teachings easy to understand and learn every lecture in your videos got very clear to me and easy to understand, I've watched them all. Thank you for posting your lectures, for people like me you have helped me bring back my confidence in learning and achieving my goals. As an advice for those kids who had a bad academic performance and lack confidence in continuing studying ... DON'T GIVE UP, is never too late to restart and continue your goals.

[@lecturesbywalterlewin.they9259]

Very nice!

[@wong2b]

I couldn't agree more. It is never too late, I got my BS in Electrical Engineering at the age of 45 with a GPA of 3.85 and I barely made it through high school. I guess it took 27 years to learn how to be a student.

[@rigdigwus]

not it is because you didnt care about it as a kid but now you realise it actually is quite interesting

[@AlienRelics]

Almost all of what I know about physics and electronics, I learned on my own.

[@AkamiChannel]

Ogeid Zepol Dr. Physics A is also nice

[@nobodyyouknow9839]

This the best way to utilize your time by wacthing your lectures

[@deepclasses-socialsciencef8427]

Best way to utilize OUR time and not YOUR time!!

[@popsynthyarby5055]

I could not believe that when I moved my polarized sunglasses over the screen I saw that the smoke was really polarized! Then it occurred to me that ALL of my monitor's light was polarized. Thank you for the masterful teaching.

[@MartinVerkest]

with a rotatable polarizing filter (to camera lenses for instance - can be used on a 'naked eye' too..., ), it is possible to look 'into' the water (removing the flickering....or add...just attempt/try), standard photography knowledge.

[@youngbloodbear9662]

Mr. Lewin, I've known about your lectures and enjoyed them since I was about 10, now that I'm in highschool and have an understanding of algebra and such, I've been able to begin going through your lectures and actually appreciating the impeccable fluidity your lectures have and how clear you are able to demonstrate the topics of 8.01-8.03.... It really is amazing. I'm on track to go to MIT or similar, all honors or AP classes, but it's almost not worth it with you gone... I lament that I can't be a student of your's but you have my respect and my thanks.

[@lecturesbywalterlewin.they9259]

You NOW are my student!

[@ericlien8760]

Tim T. Like

[@99bits46]

YoungBlood Bear I am interested to know where you at right now?

[@foxvulpes8245]

"You all look at rainbows, but most of you have never seen them" I spend a lot of time trying to see...

[@Reylarian]

its a circle, not a bow.

[@knowledge.facts532]

Spray water using your thumb on wall in a sunny day ,you can see rainbow .

[@pinklady7184]

You see lots of rainbows in wet countries as here in Ireland. They emerge usually after the rain stops: loose water molecules in air create rainbows with the rays of sun emitting colours. Sometimes, you see double rainbows. Triple rainbows are extremely rare. Whenever I see rainbows, I know they always point in the exact opposite directions of the sun.

[@firstnamelastname4997]

His rainbows. It's a subjective phrase. Prepare to see his rainbows. Not other rainbows. He doesn't know about those rainbows. But them, he has a relationship with them. Not the stranger rainbows of your past. Spend more time listening. Try to listen. Be paranoid.

[@error.418]

@@firstnamelastname4997 "Be paranoid." 😂I hope you mean skeptical, inquisitive.

[@EvaTruve]

"Knowledge adds and never subtracts." At difficult times it's something that cant be taken away from you.

[@mistertornado2303]

Professor, I first found out about you when I watched a video on KZbin years ago called "Professor Beats Student". I have since watched nearly all of your lectures that have been made public and thoroughly enjoy how you engage your students and your philosophy of teaching. You are an inspiration to me, a fellow educator, and you truly make physics fun and enthralling for everyone. As a Christian, I see everything as the manifestation of the glory of God in His creation - and I'm aware that you're an atheist and do not perceive it like I do. However, the way that you convey these topics, makes me more in awe of what God has done. So thank you, Professor.

[@vjohnification]

Amazing professor! Every time I see his lectures, he thrills me.

[@TheMTBChannel]

Thanks Walter. I'm 56 and have done physics and engineering along the way and learnt a few things from this. Always a good day when you learn one thing let alone more. Thanks again.

[@AhmadHddad01]

I really wish that i was in your class someday. Ur great man professor.

[@miguelangelsimonfernandez5498]

This evening I remembered this very talk of yours with a friend who is an experienced ophtalmologist. She was exhausted after a congress that tool place this weekend in Madrid, Spain. We were talking about the neurophisiology of sight she told me that western Sahara tribesmen (today more or less extinct) only see three or four colours, white, blue and sand mainly. No greens, for example. thank you once more for these beautiful and heart, or should I say brain, comforting lectures.

[@Ferndalien]

I had to take 8.03 as a sophomore in 1973. Prof. Lewin lectured, and his lectures were filled with formulas and I could barely keep up taking notes and always at the end there was a demonstration that brought the formulas to life. Not just a great, engaging lecturer, but a brilliant lecturer.

[@lecturesbywalterlewin.they9259]

wowwww so you were one of my students at MIT. My 8.03 lectures of 2004 ar now on my KZbin channel. I can assure you that they are much much better than my 8.03 lectures in 1973.

[@AGhulam73985]

Doing post grad degree in Economics and loving physics Because of Prof. Lewin ! Inspiration for teachers

[@lecturesbywalterlewin.they9259]

Thanks, Aribah, for your kind words

[@rishavkumar9509]

When ever I found found your video in my recommendation I just start watching like a TV serial ....this is interesting. Thank you so much sir

[@sathiyamoorthydakshinamoor1736]

Prof Walter Lewin is the best to teach Physics. Any one, irrespective of the educational background, can understand his lectures. MIT is the blessed Institute to have him. Thanks to KZbin to bring his lectures to all.

[@abhilashhazarika7790]

Monday's my biology paper and IDK why I am watching this with my bio textbook opened....i guess there's something spellbound bout this man n his way of teaching....RESPECT to thee sir

[@vivek4991]

I have an exam of digital signal and processing tomorrow and here I am at midnight learning about colours.

[@pala_sh_arma]

Bro.. I have biology today and it's 4:39 am

[@SumitKumar-zx4vc]

Hey man u r kind like me

[@vijaychoudhari609]

Wonderful.....thanks to KZbin , I learn so much now sitting on the arm chair which I missed out about 55 years ago..... Thank you so much .....

[@worklion50]

Right there with ya...

[@afterthesmash]

When I play with my KZbin playback rate, the colors do change a bit for different playback speeds.

[@olalidehorn8291]

1,75 x normal speed, the spinning wheel is working!

[@MO-em6ex]

Good to follow and understand! Love Physics like this! You can see that he‘s living the stuff he‘s teaching! That’s incredible!!! Thank‘s for this Video!

[@stevelenores5637]

Paused video to confirm it goes back to black and white.

[@stevelenores5637]

@Frank Heuvelman True enough, pausing is for doubters like me. That is what makes a scientist. Confirmation not faith.

[@sanderd17]

I wondered whether the camera also picked up the effect. Apparently not. But I do see the colors in the reverse order as he tells them. Something to do with mirroring or refresh frequencies?

[@RWBHere]

@@sanderd17 That's interesting, because I saw the colours as he described them, before he described them. And I paused the video to confirm that the effect is real.

[@loupiotable]

@@RWBHere I've seen no color :(

[@electricpaisy6045]

It impressed me pretty much that this effect worked even on camera with the fps number and all that.

[@homeryura]

Your lectures are most interesting, most spectacular and easy to get at the same time!

[@lecturesbywalterlewin.they9259]

:)

[@uendimusta3215]

This is the kind of teacher every school needs

[@MrRipsaw1]

WOW!! 52 years old and I learnt lots that I thought I knew, however... Mystery 1: Why does the sun at sunset sometimes turn green just before the it vanishes behind the horizon? Mystery 2: Why is KZbin Recommendations making this video popular again in December 2019? (I'm glad it is)

[@lecturesbywalterlewin.they9259]

google "green flash"

[@happyscience8962]

Actually Great lecture. I didn't love physics before watch his lectures.Thank you so much..He is greatest..Now I love all sciences..I proud to say reason is Prof.Walter Lewin..

[@lecturesbywalterlewin.they9259]

thanks for your kind words

[@uspsrinivasaditya]

In my childhood I had a question in my mind whether rainbow is 2D or 3D! This video explained it all!

[@johnkendal8303]

How lucky those students were, i hope they all appreciated their good fortune.

[@titi08]

Thanks to you, I now have the explanation for rainbow. I'm very grateful.

[@RakibulIslam-yz3gn]

Professor Lewin, I LOVE your lectures so much! They are so interesting, informative and easy! :D

[@lecturesbywalterlewin.they9259]

thanks Rakibul for your kind words

[@bindujose2954]

The channel's name is so appropriate. Your videos do really make us fall in love with physics.

[@jonathoncarter9817]

I drink beer on Friday nights and watch Prof. Lewin's lectures. He's such an entertaining and understandable lecturer!

[@lecturesbywalterlewin.they9259]

:)

[@dirksaenen436]

Absolutely fabulous. Best way to spend the Covid-19 lockdown is to watch and rewatch the lectures !

[@dirksaenen436]

on the other hand : damn Walter, rainbows will never look the same again. ;-) Thank you

[@user-be4yc2vr5c]

I recommend all your courses; and your teachings on physics and the like that have been offered for free via youtube(even if youtube themselves suck lol) have been an invaluable resource to me in life. Thank you. Truly. If I was forced to try to participate in the slave making "education" system to get this and not the comfort of my own home with zero pressures for free I would have missed out beyond what I care to even imagine. I truly see the world differently now and my love for science, inventing, teaching, and free independent learning has exploded.

[@prabhakarrao4922]

A big hello from Auckland New Zealand. I taught physics to high school seniors way back in the 70s but your lecture presented here is really inspiring. I enjoyed those days. I too believed and practiced blending practical demonstrations whilst covering theory. It is an incredibly powerful way of reinforcing learning. Thank you very much.

[@lecturesbywalterlewin.they9259]

Wow, thank you!

[@hassanhan9124]

Humor, science and the love of sharing knowledge; that's Mr Lewine. What Professor...!

[@kid_nero61]

This dude really just smoked a cigarette to eagerly explain and demonstrate a complex concept of natural phenomenon in a lecture. Props.

[@shubhkarmansingh1641]

Really you are the best physics teacher ever i have seen. Such a knowledgable person. The way you make things clear is awsome. If i get a chance to meet you i will be really fortunate

[@pramodjha8201]

Mr. Lewis is really Godly scholar & teacher. I would love to call him Mr. Physics. He makes Physics so loving. No doubt, he must have made thousands of Physics-lovers. Me included. God bless him, Pramod Narayan Jha B. Tech. 1970 76. Retired mechanical design&project engineer , Presently a Lychee farmer & a humble science teacher to poor & needy kids absolutely F. O. Cost

[@SanjayPandit-sc9xx]

Most important lecture for me .Thank you sir .by best proffeser of the world (you).

[@lecturesbywalterlewin.they9259]

apod.nasa.gov/apod/ap240510.html

[@marceld6061]

This lecture should be MANDATORY in high school in Hawaii! The land of rainbows, blue skies and sunsets!

[@wlan246]

23:57 As a great philosopher once said, "If it ain't broke, you're not tryin'!"

[@wirsindhelden0]

He's such a legend that I'll bet he just REALLY needed a cigarette break and managed to seamlessly work 4 of them into his lecture without anyone noticing 😂 But in all seriousness - this man, is an absolute inspiration. Somehow, every video I watch is more intriguing than the last. I only wish I had found his videos sooner!

[@abhijitsingh734]

Your lectures are so much easier to understand.....some times I thought that I m a Proffesor😅😅😅.....thnxxxx

[@ianmoone2463]

I really love this wonderful lecturer on how simplified his lectures were. And I really wonder for a long time now, how did he ever made that straight dotted line in just one stroke.

[@Bunny_Aoife]

I read your comment before watching the video, and I thought I had seen quite a few professors do super straight lines, dotting at extreme speeds and the like... I thought I've seen it all, how impressive could this dotted line be... but holy shit, I wanna know how he does this... it was awesome.

[@charlesclements4350]

Go back and look carefully at the way that he is holding the chalk. Notice that the chalk is flat on the end. The chalk grabs then skips as he drags it across the board.

[@charlesclements4350]

Ian, look at the way he holds the chalk. It grabs then skips as he drags it across the board. Personally, I hate it because it set up a horrible vibration in the finger.

[@faefesd4810]

@@Bunny_Aoife there are 3 minute tutorials on yt

[@tonydawson1760]

Yeh you can only see it when viewed from a 42 degree angle or somethin 🙈😷

[@marketmail49]

I am so happy I could calculate the values of phi 😅. Thank you, Professor. You are always my "mentor".

[@lecturesbywalterlewin.they9259]

You're most welcome

[@JoinTheTechnicians]

*_* Pause the video and you see in each frame the B&W color wheel is in fact, truly B&W even while rotating!

[@varatharajaperumal7909]

Thanks God I found this channel

[@mariocesarsousa]

Awesome. The power of teaching comes from the love for doing it.

[@lecturesbywalterlewin.they9259]

Mario Cesar Sousa Indeed. Read my book "For the Love of Physics"

[@bitscorpion4687]

you are my favorite physics teacher !!!!!!!! i can understand many things i couldnt understand!

[@lecturesbywalterlewin.they9259]

GREAT!!

[@paulholzherr2993]

Great stuff! I like the way he creates the dotted lines with the chalk!

[@lecturesbywalterlewin.they9259]

kzbin.info/www/bejne/qJLYo59qqJWjoLc

[@Positive_Videos_calm]

@@lecturesbywalterlewin.they9259 I watched this video a day before yesterday. I hope you yourself enjoying too. 🤗

[@rogergr5019]

This man is from my hometown in the Netherlands. Love him

[@estellevanstaden5883]

I was once very lucky. Not only could I see the primary and secondary but a tertiary rainbow as well. On my birthday as well!

[@dariusmccormack7793]

the most amazing thing about this video was the part where he has some magic chalk that makes dotted lines and a funny sound. What sorcery was that??

[@a.j.bertenshaw4539]

Darius McCormack I think he’s just angling the chalk on a sharp angle away from the direction he’s dragging it so that it skips over the board

[@crackwitz]

@@a.j.bertenshaw4539 that's his signature move. anyone can learn it within minutes but he has a lot of practice

[@error.418]

He has a video on just that and how he does it. Someone even made a compilation of the times he has done it. Just search in KZbin for: Lewin chalk

[@zaarakhan7678]

i never saw any teacher like him ...he is a great man and great teacher...i wish i can meet him

[@lecturesbywalterlewin.they9259]

Come to Cambridge, MA USA and we can meet!

[@zaarakhan7678]

wow its so nice that you replied me:) now i will come as soon as possible

[@pala_sh_arma]

I have biology exam today ( in an engineering college). It's 4:40 am and here I am... just finished watching this.

[@yngwar8606]

The real magic for me is - how does he draw these dotted lines?

[@MCRmechanic]

He's so fast at angle calculation and expression. A true master and a pleasure to watch.

[@lecturesbywalterlewin.they9259]

:)

[@coffeecuppepsi]

14:28 he begins by spinning clockwise, so if you focus on the inner ring, (red) you'd see the long black rest, then stripes, then the uninterrupted white. when he spins it counter clockwise it's the outer ring that follows this pattern.

[@timhallas4275]

He's right. When you know how rainbows form and why, they have a new kind of beauty,. ..and what makes that special is the simple fact that you know where to stand and where to look. ..makes you look like a wizard to your friends.

[@lecturesbywalterlewin.they9259]

Knowledge always adds, it never subtracts. Knowledge of rainbows is the "hidden" beauty, "hidden" from those who do not know.

[@timhallas4275]

Lectures by Walter Lewin. They will make you ♥ Physics. Watching Walter in these videos makes me sorry that I didn't get to MIT when I was a young knowledge seeker. No doubt, these science teachers will be better at their jobs after this experience. I know it helps me tremendously.

[@lecturesbywalterlewin.they9259]

Thank you for your kind words. All science teachers were given a DVD of my lecture for many years. I gave this lecture (or something very similar) every summer for at least 5 years (probably more).

[@timhallas4275]

Lectures by Walter Lewin. They will make you ♥ Physics. Your very welcome. These lectures have helped me gain a more complete understanding of the nuts and bolts of physics, as well as an greater appreciation for the mathematics involved in this amazing field. Thank YOU my friend.

[@Holobrine]

High school physics student here. I understood most of the concepts but I haven't yet learned Snell's law.

[@13Gangland]

Easy, brain makes world pretty colors.

[@titusnelson9499]

Absolutely Fantastic. Just fantastic

[@SG-dw8jh]

what a privilege it is to be ur student.

[@gurugnorm]

At 45 minutes you show an ad of a Rainbow Maker that my husband Norman Hughes created. The ad is an awful copy. The plastic rainbow maker does indeed create a DOUBLE RAINBOW that shines on a wall when the sun shines through the plastic. We sold them via mail order for about 10 years. They were slowly injection molded using only one brand of plastic that would be completely clear with no distortion. Norman was an Academy Award winning mechanical design engineer. Camera design, CO2 lasers, robotics, infrared spectrometry were some of his specialties. He passed away in 2012

[@lecturesbywalterlewin.they9259]

Thank you very much! :)

[@johankotze42]

Many years ago there was a julius Sumner Miller. (1970s?) He had a similar approach!

[@thomasweaver4791]

the ultimate showman and teacher. Stay healthy and happy,

[@lexsmith8689]

well I was born in czech republic and eversince I started to go to kinder garden , my teacher told me, when nI asked her how the rainbow comes into existence, she told me that when it rains but there are little of no clouds, the sun is shining on the water drops and the light then bounces of the drop´s surface and divides into different colours and she told me that this effect is called light refraction and the colours are called colour spectrum.. I remember it very clearly cuz my mother (also a teacher in the same kinder garden ) had to teach me and explain about 50 more things when we came home.. I wanted to know.. I was 5 years old.. so this is no suprise to me well apart from the value of all those angles

[@pepineric]

definitely one of the best, all my respect Mr Lewin

[@lecturesbywalterlewin.they9259]

Thank you

[@willgates32]

It is worth noting that logs to any base represent exponential growth. (The base 'e' simply relates to the property that d/dx (e^x) = e^x.)

[@kanalmatematika8498]

Prof Lewin, you're really Great. I'm very interested in your lectures.

[@lecturesbywalterlewin.they9259]

Glad to hear that

[@jonnnymoose]

Just found this......superb. I now have a new view on hitchhikers guide to the galaxy.

[@therealzilch]

Wonderfully informative and entertaining. Science teaching at its best.

[@jcinaz]

Fantastic! Science has never been so interesting to me. I learned a lot.

[@vedantjoshi1487]

Hello, Prof. Lewin. I am a graduate student from India and I LOVE teaching (especially physics) to kids who are in school. I want some suggestions from you about how to teach physics in school with minimum resources to perform experiments during lectures like you do. I am finding new ways to teach kids in Indian schools so that learning becomes fun and not boring! (I know that the question is very "not short answer" type, but I would love to read your suggestions.) and how can I forget, YOU ARE THE BEST teacher in the world! Thank You, sir.

[@GardenGrow]

Professor, I am a botanists. Still I am your audience. I have made my own rainbow by sprayer only after this lecture.

[@CosmopolitanXMan]

Interesting to see in 48:45 that in the *primary rainbow* the red bow is in the outside and the blue bow is in the inside, but in the *secondary rainbow* blue is in the outside and red is in the inside. This is like what Walter explained earlier in 41:40

[@stargazer7644]

It is exactly what he describes. He doesn’t mention the secondary bow at 41:40.

[@skeltek7487]

The spinning disk is pretty much trivial imho. Red usualy needs multiple photons to build up stimulus in the photoreceptors. So once you see the sequence black->grey->white, it corresponds to a multi-particle low-energy-per-photon situation. Blue usualy has a higher energy per photon, which stimulates the receptors immediately to a maximum with a slow fading of the stimulus afterwards. The later corresponds to the sequence black->white->grey on the spinning disk.It is probably a mechanism of the brain to better distinguish colors in low lighting.

[@shiinondogewalker2809]

if you're right, why would the red circle then appear red? if black-grey-white give enough time for our photoreceptors to detect red light, wouldn't there then also be enough time for detection of all other colors, and result in grey/white color?

[@nashgujjalu104]

What a wonderful lecture! Thank you professor.

[@lecturesbywalterlewin.they9259]

Glad you enjoyed it!

[@HowBigistheMap]

Some people tell me that I sound just like this man when I'm talking English. I'm Dutch too.

[@lecturesbywalterlewin.they9259]

:)

[@GreasyTrout]

The dutch accent is indeed very recognizable, but atleast he's not like Van Gaal.

[@sage7309]

In my fifth grade class we made small versions of the disk at 14:05 as a class project, I forgot about it until I saw this video in my recommends.

[@Trashloot]

I dont see anything D:

[@error.418]

@@Trashloot It doesn't work as well in video. Framerate plays a big role here. It's much better with continuous time (i.e. in real life). You buy buy such disks or make your own and spin them like a top. It's called: Benham's Disk, or: Benham's Top. Search for those terms and you will find instructions to make various versions of your own, or places to buy them for cheap. It's well worth it, it's a wonderful illusion.

[@marcinzadora5503]

im not bright,but this guy got this what albert E was talking about,if you cannot explain something to a 6 years old child,you don't understand it.great teacher(things are boiling in my garden shed)

[@Bunny_Aoife]

So the Ultimate Question of Life, the Universe, and Everything might be, "At what angle relative to the sun do you have to direct your gaze to experience a proper rainbow?"... Quite satisfying, at least to me.

[@rigatonijacobs]

16:06 "If you want to explain that, you don't want to be in physics because that's outside our domain" This to me seems to suggest the opportunity to express the reason philosophically and even metaphysically. Humble man

[@danadane9786]

I love learning from you!

[@lecturesbywalterlewin.they9259]

I'm so glad!

[@wt_heck]

as a photographer this is amazing to know!

[@felixcihonski7103]

If you are miopic and you take your glasses of, the colors of the spinning wheel will disapear, they are visible only with a clear and focused sight. The better you focus the brighter the colors become.

[@betascire2607]

I really love his teaching style.

[@sujitmohanty1]

What a lecturer!

[@XxSwiftDemisexX]

For anyone interested in an extension of the first black and white to color experiment, google Wendy Carlos Color Experiments. She was able to achieve the same effect by splicing a black and white photo with a red shifted copy instead of overlaying them. Great demonstration of resolution averaging working in the brain. Zoom in on the pictures after looking at them.

[@dogscats8141]

My favorite teacher

[@junaidkhan6329]

I love you sir...i love your wat to teach physics..you give feel on physics.

[@lecturesbywalterlewin.they9259]

Glad to hear that

[@junaidkhan6329]

@@lecturesbywalterlewin.they9259 sir iam also glad on your reply.. because you are the Best teacher...so please sir upload more and more videos of your lectures because iam a hunger to study physics with concept as well as with feel.....thank you sir....god bless you....

[@alex92569]

The colors visible on the rotating disk could be explained by the different exposure/relaxation time curve of the blue, green and red color receptors in the eye retina (exponential in time with different time constant for different receptor types).

[@alexesskew2631]

Alex Petrov, when he did the fist one, I couldn't see the colors, but when it went in the other direction, I saw the colors

[@joshuataylor71]

I loved this lecture!

[@The98303]

God of teaching. 🙏

[@worklion50]

For all those "amazed" with the chalk dotted line "sorcery", either you are new to physics, or; this might not be a hobby well suited to your present skill set. Jus' sayin'. Great teacher, DOES make learning fun.

[@keithharperink3363]

did anyone else the outer and inner circle colors are the opposite of what he said either way

[@DownhillAllTheWay]

At 57:45, "Once the light bounces off the screen, it is no longer polarised" And yet - 3D movies use polarising glasses - 45 degrees on one eye and 335 degrees on the other (where 0 degrees is vertical). Light is polarised at two projector lenses, and is apparently still polarised after it bounces off the screen. Maybe it's a screen surface that is optimised for the purpose. Actually, I think the more modern ones use left and right circular polarisation - but the same principle applies.

[@hans-joachimbierwirth4727]

AFAIK they use a special coating for that.

[@MxAvA]

At about 13 minutes I was supposed to see colors, but I only saw red, black, and white. Well, I guess I'll have to watch more to see if that was just me or what.

[@jayluck8047]

I saw the colours on the spinning wheel in reverse. On the inside at first, outside when he reversed the motor.

[@barani0045]

even I too feel the same think you seen in circle....