Super High Voltage - Why is the Sky Blue - Why are the Clouds White and Why are the Sunsets REd?
Пікірлер: 127
@Wanted_Tiger7 жыл бұрын
1 hour well spent
@mindscraped7 жыл бұрын
Back in the 70s i was working for a TV repair man . And as you remember television sets were analog and all had cathode ray tubes. The color TV sets used 25,000 volts created by the fly-back transformer through a tube diode into an electrode inside a rubber cap. The TV repairman held the cap in his hand while the set was on ! !. You could see lots of large electrical arcs coming out and into his hand. And he had no adverse effects.
@aln40753 жыл бұрын
As this man said:"teachers who makes physics boring are criminal"so i guess my teacher is a serial killer
@amitroy82352 жыл бұрын
I was reading the book "for the love of physics", read there about this experiment and came here to see.... its amazing....
@pratikkumar11182 жыл бұрын
Same here lol
@arc165 Жыл бұрын
Same here mate 😊!
@paneertikka40659 ай бұрын
Same here lol
@fjs1111 Жыл бұрын
Your so funny professor Lewin, love you!!
@anitapawar31363 жыл бұрын
Amazing !!!! Great physicist 👏🏻👏🏻👏🏻
@kanato61526 жыл бұрын
hi,professor. I'm from Japan. I have been wanted to know why the color of sky is blue since I was a elementary school student. you answered my questions thank you. and I love your lecture.
@lecturesbywalterlewin.they92596 жыл бұрын
:)
@pratimakaushal40784 жыл бұрын
Sir I am just amazed. I just hope I could have a friend like you. Love from India. Physics enthusiast preparing for JEE and Medical Entrances.
@sourabhtripathi09864 жыл бұрын
Both?
@Aryan-po4mw3 жыл бұрын
Best physics lecture ever watched.
@Zeyadhany Жыл бұрын
you made me in another world ,Dr walter ❤️ thanks alot
@lecturesbywalterlewin.they9259 Жыл бұрын
My pleasure!
@abhinavverma37694 жыл бұрын
It is mind-blowing , amazing to see sunset in a lecture hall.
@lecturesbywalterlewin.they92594 жыл бұрын
:)
@tanmoy77773 жыл бұрын
Wow...that's really great ❤️💞❤️💞❤️💞❤️ one of the best physicsist and also best teacher
@lecturesbywalterlewin.they92593 жыл бұрын
Wow, thank you
@navneetkumar7155 Жыл бұрын
Thank you sir
@lecturesbywalterlewin.they9259 Жыл бұрын
Welcome
@ujjainisingharoy34893 жыл бұрын
Why these videos have so scant views and likes... it should touch millions.
@ajayrajan88825 жыл бұрын
Exemplar of real scientific education.!
@dr.parichitarc67324 жыл бұрын
sir, you are the best teacher I have ever seen. Love from India
@subashkc76742 жыл бұрын
Sir you will be immotral even after 1000 of years because whoever will see in the next generation will love your lectures.I love so much your lecture sir. You are great physicist who made 100000 of people love with physics. Thank you for your all precious lectures sir. I am also lover of physics . Everywhere I see physics that you had made me.
@chaitanyakasani77188 жыл бұрын
professor, what is the significance in Rutile Titanium oxide prism. as we also find titanium oxide in other forms like ilmenite, anatase etc.. ??
@lecturesbywalterlewin.they92598 жыл бұрын
I have no idea. Try Google.
@dxdx6668 жыл бұрын
Hi professor Lewin! 26:25 Q: Are you positive that VDG could charge you all way up to 120 kV)?
@lecturesbywalterlewin.they92598 жыл бұрын
+dxdx666 I am reasonably confident.
@dxdx6668 жыл бұрын
I asked because I've done measurements in the past in such experimental setups that led me to conclusion it was quite difficult to charge human body by small VDG to potentials over 100 kV (even during dry days ). Usually the leakage of the charges from the body is to great for small VDG to compensate and voltage drops significantly when one loads the machine
@lecturesbywalterlewin.they92598 жыл бұрын
+dxdx666 I do not exclude that it was lower than 120 kV
@hseverins5 жыл бұрын
Hi Walter, Henny from Holland (Oosterhout ) again! Last week i spend one weekend in Luxemburg . And i saw something spectaculair , Well i think it is!!! I proceed in dutch! De zon was al achter de horizon verdwenen, en er vloog een vliegtuig over, met de witte strepen achter zich ! Maar vóór het vliegtuig , was er een donkerblauwe streep , die het vliegtuig léék te volgen! Ik heb dit nog nooit gezien! Zou dit de schaduwvorming van het vliegtuig kunnen zijn? Ps in de blauwe lucht , was dit een donkerblauwe streep, en ter hoogte van een witte wolk, was dit een lichtgrijze streep! Groeten uit Oosterhout !
@lecturesbywalterlewin.they92595 жыл бұрын
dat is heel waarschijnlijk de schaduw van het vliegtuig geprojecteerd op nearby thin clouds of de schaduw van een contrail.
@meikejune40092 жыл бұрын
The experiment with the two water buckets is very interesting. Seems to be mysterious. I will look, what you have done there.
@lecturesbywalterlewin.they92592 жыл бұрын
google "Kelvin Water Dropper"
@meikejune40092 жыл бұрын
@@lecturesbywalterlewin.they9259 I googled it. And now I know, what it is, that Generator you used. And I had a very peaceful day of 2. Advent. Because I'm total alone. And I thought, sad that I will never be able to go on Windsurfing at France at the Atlantic, because I'm to old for trying it. I did it at the Baltic Sea once. Walter, we must finish that exercises, too dangerous for us.
@meikejune40092 жыл бұрын
@@lecturesbywalterlewin.they9259 You are a wonderful friend, Walter Lewin and I love you.
@zolbooenkhjargal26708 жыл бұрын
Hello Professor, I am from Mongolia , Can you upload this lecture to English subtitles please. thank you.
@lecturesbywalterlewin.they92598 жыл бұрын
+Zolboo Enkhjargal Most of my lectures have subtitles but not all. I cannot hang that anymore.
@aniketnandy31246 жыл бұрын
Professor, if in Rayleigh scattering, red light is scattered the least, then I think that red light should be more abundant in our vision as it directly reaches our eyes, the sun should then, appear red, even at noon.
@lecturesbywalterlewin.they92596 жыл бұрын
The sun radiates more or less like a 5760 K black body. During midday in the direction of the sun only a few percent of the light is scattered and absorbed. But when the sun is only 2 degrees above the horizon 99.9% is scattered and absorbed in the atmosphere that's why the sun is then red.
@junkiatfighting4sab4774 жыл бұрын
What's the sound at 18:43
@feliwx40876 жыл бұрын
professor , it is an awesome lecture , but i have some doubts ..... 1. in the last experiment of yours , why does the colour of the sun change gradually , is it because , you are adding more and more sulphuric acid gradually. 2. why doesnt that light refract
@lecturesbywalterlewin.they92596 жыл бұрын
1. the closer the sun comes to the horizon the more atmosphere is between the sun and me. In my demo the precipitation of sulfur increases in time (chemistry). 2. ofcoz there is refraction but I shine the light through the liquid at near 90 degrees.
@feliwx40876 жыл бұрын
oh ok sir
@ngok90635 ай бұрын
had a debate with my friend ----- does rayleigh scattering of light depends on particles or on wavelenght of light
@lecturesbywalterlewin.they92595 ай бұрын
use google -its all there
@meikejune40092 жыл бұрын
Is ist about lightning 🌩?
@winproduction75858 ай бұрын
Professor I have the question. You said that the cloud is orange when the sun is near set or rise? Is it because the the only leftover color is orange and it scatter the particle in the atmosphere and hit cloud? If so, why the cloud is not blue when the blue scatter light hit the cloud?
@lecturesbywalterlewin.they92598 ай бұрын
Rayleigh scattering removes a major fraction of the short wavelength of the solar spectrum.
@winproduction75858 ай бұрын
I still don't understand. Could you explain more?@@lecturesbywalterlewin.they9259
@sarkarrudra2 жыл бұрын
I would like to ask Prof . Lewin why did he use the tougue?
@physicsfoundry7429 Жыл бұрын
Dear Sir , During the sunset experiment how much quantity of hypo and sulfuric acid did you use ?
@lecturesbywalterlewin.they9259 Жыл бұрын
I do not remember
@Protegit6 жыл бұрын
I dont get one thing... if sunsets are red, why arent sunrises red too? I mean... the dust is still in the atmosphere and blocks blue (and other) light, so... why is it not red?
@lecturesbywalterlewin.they92596 жыл бұрын
of course they are also red
@Protegit6 жыл бұрын
Lectures by Walter Lewin. They will make you ♥ Physics. Never seen a red one xD I will wake up early tomorrow and see for myself, I can record it you want, sir :D
@priyabratadash381 Жыл бұрын
Great demonstration of scattering of light by smokes of cigarettes but I think it would have been better if Walter would have preferred the Indian way of glowing incense sticks before the light than blowing those harmful cigarettes.
@lecturesbywalterlewin.they9259 Жыл бұрын
how do you then change the color from blue to white?
@priyabratadash381 Жыл бұрын
@@lecturesbywalterlewin.they9259 Really witty full reply from you Sir. Actually I was going through your famously written book " For the love of physics". I have enjoyed everything written in it and it aroused within me a sense of wonder, a way to see the truth through the eyes of physics. But one thing that put me in worry is the experiment of scattering of light by the smokes of cigarettes. I thought cigarette smoke would have harmed you and that too holding smoke within lungs would have caused difficulties for you. So I thought of an alternative and incense sticks came to my mind. And to turn blue light to white light artificially produced smog could have been used. But Sir truly I like your daredevil demonstrations to show the beauties of physics. All your efforts are unmatchable and extraordinary. I have great love and respect for you. Right at this time your written book is on my table. Love from India Prof. Lewin.
@meikejune40092 жыл бұрын
This Buket-Beckett is a sculpture! You are an Artist, Walter. (Meike,Third of December 2021.)
@souravchattaraj27297 жыл бұрын
sir why dispersion occur on prism and not in rectangular glass salb????
@lecturesbywalterlewin.they92597 жыл бұрын
Watch my lecture kzbin.info/www/bejne/n6PTm6qOpcZnrrc
@EurekaRecycler8 жыл бұрын
Thank you. What about the color of jet sprayed geoengineering materials for weather modification? GeoEngineeringWatch.org
@lecturesbywalterlewin.they92598 жыл бұрын
+EurekaRecycler I suggest you ask Google
@usamahasrat4 жыл бұрын
Sir I want to understand the phenomenon of "mirage" on roads in hot summer when it seems water on roads. please if you have link of your such lecture. share with me
@lecturesbywalterlewin.they92594 жыл бұрын
this is the most common mirage - See it every year many many times. Google "mirages" and it will be explained. It's due to the temperature gradient near hot roads which courses a density gradient in air.
@usamahasrat4 жыл бұрын
@@lecturesbywalterlewin.they9259 your highness my dear sir
@usamahasrat4 жыл бұрын
@@lecturesbywalterlewin.they9259sir!, I have googled it! I have understood the temperature variance as well. But I'm confused about the " topretendwater" , is it reflection of sky on roads or just reflection of water droplets in air?
@gazlanham22506 жыл бұрын
I SAW A WHITE SUNSET YSESTERDAY 14TH APRIL 2018
@mohdreyaz10377 жыл бұрын
Sir can you please tell me about scattering cross section?
@lecturesbywalterlewin.they92597 жыл бұрын
use google
@noormohammad53764 жыл бұрын
@@lecturesbywalterlewin.they9259 I love how you answer everyone
@trustinphysics54436 жыл бұрын
hi professor I want to ask that If read in your book for the love of physics that sky is dark at moon because there is not atmosphere but sky is also black on earth
@trustinphysics54436 жыл бұрын
at night
@neldungca85243 жыл бұрын
The blending of white light and dark shadows is blue
@Forever_PTE7 жыл бұрын
sir why doesn't yellow or green light scatter. Their wavelength is less than blue light, so scattering should be more.
@lecturesbywalterlewin.they92597 жыл бұрын
wavelength blue is 450 nm red 650 nm blue is the shortest
@Forever_PTE7 жыл бұрын
violet has smallest wavelength. The why only blue is scattered
@lecturesbywalterlewin.they92597 жыл бұрын
the sun has very little violet in it's septrum also our eyes are not very sensitive to violet
@maheshchandra91646 жыл бұрын
hello sir ,how u concluded Sun's spectrum consists only small portion of violet . why not sky is violet r indigo
@maheshchandra91646 жыл бұрын
am not satisfied with ur explanation
@nitukaur97975 жыл бұрын
Sir,At 5:28 by in general do you mean ohmic resistances
@lecturesbywalterlewin.they92595 жыл бұрын
I watched from 5:00-7:00 it's crystal clear ai cannot add to it.
@nitukaur97975 жыл бұрын
Ok sir thanks for your reply.you re fast
@nitukaur97975 жыл бұрын
Sir do you have any astronomy lecture playlist on your channel?
@eliteconvintagerugbyreviva20653 жыл бұрын
Sir, how is the sky still blue in photographic images?
@DavidLindes2 жыл бұрын
I guess you expect it to be otherwise? For what reason? My answer below, though I’d encourage you to think about it a bit before clicking on “see more”. In short, the same scattered light that goes into our eyes is also what goes through the lens, to expose the film or digital sensor. So, if the film or digital sensor are set up to differentiate different colors of light, and the scattered light is blue, then that’s what will turn up when we process (whether chemically or electronically) the image. Right?
@raj-ytinternational72404 жыл бұрын
Why does kelvin water dropper creates high voltages?
@lecturesbywalterlewin.they92594 жыл бұрын
I explane that in my 8.02 lectures, watch them
@checheno016 жыл бұрын
Professor, first of all I need to thank you for your video lectures. They help me a lot with my physics students. I'm very interested in the sunset experiment, honestly to include the drama I want to try to replicate it in my class but honestly I don't undestand very well the composition of the solution in the bucket. If you can give me please the composition and the concentration of both the bucket solution and the sulfuric acid I will be very grateful to you.
@lecturesbywalterlewin.they92596 жыл бұрын
contact Andy Neil at MIT. aneely@MIT.EDU
@meikejune40092 жыл бұрын
Walter I have some funny ideas with that bucket-experiment. I thought about Beckett: Waiting for Godot.. We are.all waiting. I'm lost. Should I go there or to another place.or better stay? But the experiment is nice. I want that you help me here to build that bucket Beckett experiment.
@lecturesbywalterlewin.they92592 жыл бұрын
Waiting for Godot is one of my favorite plays.
@meikejune40092 жыл бұрын
@@lecturesbywalterlewin.they9259 I saw it once in a Theater. It is a bit scary, because it isn't clear, if Estragon and Wladimir are dead or alive. I think, before Waiting for Godot we were in : Max Frisch: Biedermann und die Brandstifter. I hope you know that. Let's wait.
@meikejune40092 жыл бұрын
@@lecturesbywalterlewin.they9259 I love more this play " Mirandolina" by Carlo Goldoni. You have never heard about it, Walter Lewin, but "Mirandolina" is one of my favorite.
@aarzoosrivastava1102 Жыл бұрын
Sir, subtitles are disabled please inable sir🙏🏻🙏🏻🙏🏻🙏🏻
@lecturesbywalterlewin.they9259 Жыл бұрын
there are no subtitles - they can be added if someone sends me the cc file.
@nik56118 жыл бұрын
what if we have a very high current but a very very low voltage can it kill you??!
@lecturesbywalterlewin.they92598 жыл бұрын
+niki isufi Voltage is unimportant; what kills you is current.
@nik56118 жыл бұрын
+Lectures by Walter Lewin. They will make you ♥ Physics. Thanks Mister Lewin for the response :)
@fishingandmusic988 жыл бұрын
+Lectures by Walter Lewin. They will make you ♥ Physics. Excuse my stupid question sir, but is it false to state that the value of voltage is what allows the current to flow through human body, according to Ohm's law V=RxI? in this case, the higher value of current that can go across the body is determined by human body resistance, isn't it? therefore, lower is the voltage, lower is the current that can flow if resistance is constant. so if voltage is low, severe damages should not occur . where am I wrong?
@lecturesbywalterlewin.they92598 жыл бұрын
High Voltage, low current will not kill you. I touched the vdGraaff which was at 300,000 Volt. The curgent through me was very low. I am still alive.
@fishingandmusic988 жыл бұрын
+Lectures by Walter Lewin. They will make you ♥ Physics. this is clear to me but I believe that voltage like 12V (as it is in car batteries) even if current may be quite high, the current that flows in the body is usually low due to resistance, which may vary from point to point and which is influenced by other different elements, right?
@meikejune40092 жыл бұрын
Walter must I smoke three cigarettes parallel to repeat that experiment?
@lecturesbywalterlewin.they92592 жыл бұрын
1 cigaret will do. But I always add drama to my lectures.
@meikejune40092 жыл бұрын
@@lecturesbywalterlewin.they9259 You Are that Drama, you don't add it.
@yuktarathore6573 жыл бұрын
Who r those 6 dumb people who disliked this lecture?
@gazlanham22506 жыл бұрын
YOU DID THAT ON THE EARTH CANT NASA DO IT ON THE EARTH TOO
@madforfact2 жыл бұрын
God is teaching here and I am watching him how lucky I was ? 😱
@sirfawwadbaloch4 жыл бұрын
Sir I need your mail plz
@lecturesbywalterlewin.they92594 жыл бұрын
it's no available
@neldungca85243 жыл бұрын
But sir you are totally wrong from your observation I think the background is the black shadows why don't you try to change the background with other color rather than black shadows say red shadow you will get an interesting another conclusion try to experiment further
@rojesdai573 жыл бұрын
The lectures of physics are totally different in Nepal than yours they don't perform these experiments for us like you do.
@science-y92093 жыл бұрын
Why is he trembling..
@Rookies1032 жыл бұрын
Medical issues,
@oms85134 жыл бұрын
The audience were so dumb... Just responding in laughs... No answers to the question such a great professor... When he wanted a volunteer, after 5 mins a girl came..
@markfreedlund5 жыл бұрын
Anybody else watching this during the super blood moon and getting how it works right now?