The Speed of Light in Glass

[Phillzilla6]

@unknownXV it doesn't slow down, it just runs in to things along the way, making a longer trip, its going to same speed but not taking the fastest route, and it's called wave particle duality, look up his video for it, it explains it well

[HappyGuyxlii]

This guy should work with the guy who does XKCD.

[UnknownXV]

Honestly, I confess myself confused. I've heard countless times that light speed is a constant, and it can't be changed. Yet, as you say, light slows down in matter. So how is it a constant if it does actually slow down? Seems like an obvious contradiction.

Also, how can light be a wave AND a particle..? That doesn't make sense either.

[TimThomason]

[CLASSIFIED]

[SlayerKill7]

am i the only one who noticed that his president is white?....racist ahahaha

[InsaneMentalist]

@SlayerKill7 Or lazy artist.

[Zephire14]

i feel all scientific just LISTENING To you talk! :D Of course i have NO idea what you are saying.

[blooboy4747]

i came here for pink floyd

[toxicflyFisher]

thumbs up for mr president. :)

[villerend]

That was a great analogy

[chuyton]

you probably just taught me a weeks worth of reading and sitting in a class worth of stuff in less than 2 mins

[thachthewandererable]

now you need to do a video explaining about presidential speed.

[xXH3ll5xB3llXx]

Now he needs a video on Particle-Wave Duality

[Zerepzerreitug]

"going at full presidential speed" should be made into a car sticker

[wazscience]

i really enjoy this guy's drawing, always so entertaining

[samsledje]

1:11 "Door force one" literally fell down laughing

[tony5w]

i was wondering, how does the light that leaving a moving object know to go the same speed with the light that leaving a stationary object when turn on at the same time ? i had been searching that but found no answer.

[am101171]

@tony5w I see it this way,there is limit to how small intervals of space and time can be divided into, lets say that t1-t0 is the smallest piece of time one can have, and x1-x0 is the smallest piece of space that one can be displaced on. then C = (x1-x0)/(t1-t0) , one simply can not travel a distance shorter than x1-x0 in a time t1-t0, because there is no such distance. the same goes for time, one can not travel a shorter time than t1-t0, thus C is the highest speed possible.

[tabaks]

@am101171 Tony, there are no words in your rant...that a sane person would use in the same order you did.

[am101171]

@tony5w I got this explanation from a physics paper, I just soart of adopted it because it makes sense to me. Hawkings talks about a minimum time period in at least one of his books if not all of them. In simple worlds the speed of light is the only allowable speed for something without mass, because of space and time constraints, it does not have anything to do with the stationary or non stationary frames.But I would not try to convince you that I am sane. Just trying to help. regards

[tony5w]

@am101171 light dont have mass then how does it bend in space, what about the black hole when its gravity pull it in?

im imagining space and time is something like 3d grid allready laid out in the universe so these light stuff travel alone these grids like electricity through wire, i can see how that works, so does that sound about right i appreciate you trying to help , thanks.

[am101171]

@tony5w "light dont have mass then how does it bend in space, what about the black hole when its gravity pull it in?" photons that form light have no rest mass ( this is given in the physicists community), it is all related to the formula E=MC^2. but im not gonna show you more equations. I will say what the physicists say, that a gravitational field curves the space-time continue, so light just follows its normal path, but since it is curved it falls into the black hole in your example.

[am101171]

@am101171 It is no sin not to accept that view or not understanding it, but it is what the physicists community stands by. Hope it helps. If u have your own model and you can produce accurate previsions of the real world, go ahead.

[tony5w]

@am101171 i think i get it light illuminate space which it travel on for some reason that tell me matter is like space too but compacted. no the equations wont help me much, wish i did know those but my memory is too bad for that. i do have a burning desired to know how it all works cause i think once they figured out all that they will know the answer to afterlife. thanks for helping.

[musicismylife816]

We're learning this in conceptual physics XD

[musicismylife816]

Why couldn't the teacher explain it like this?!

[robinz62]

At 0:30 you say that the light oscillates the same number of times per second(frequency), and that it stays the same color, but doesn't frequency always stay the same? Also, if the wavelength changes, doesn't that change the color?

[colbyrh1]

@robinz62 no and... no

[robinz62]

@colbyrh1 ok got it, thanks :)

[thelightningsword178]

@XxDazedandConfusedx1 Minus green. There is no pink.

[JayMark2049]

A cheeseburger isn't made up of only B-zero mesons, therefore, cats are omnivorous.

[bandboy104]

time to get in the thinking chair

[gamer5122]

well i just learned more in 5 videos then i did in 1 semester of class ..who needs school

[Hammerfall3141]

You are really good at explaining things

[waterproofcat1]

you mean resume his direction because his pace never changed.

[Evoshun]

Best artwork in the world.

[FredericBayer]

What piece of music is played here at the end? I've heard it so many times before yet never found out its name...

[TheSmackerlacker]

@FredericBayer I believe that is "Stars and Stripes Forever".

[dekoduck]

u sound like Jesse Eisenberg !

[barrettfullerton]

I have zero knowledge on the matter, however this must mean that light is not travelling at its full speed through air due to it still hitting the smaller particles it connects with, correct? Meaning the speed of light will always be calculated differently (Slightly) depending where you are and what is in the "air"? I'm probably wrong but to me the logic seems plausible :D

[MadCat360]

Gamma rays emitted in the center of the sun take about 100,000 years to reach the surface because of exactly this mechanic.

[911peter2]

PICTURES MAKE EVERYTHING MORE UNDERSTANDABLE :)

[WillBlocher]

Am I crazy? I thought energy was inversely proportional to WAVELENGTH.

[cen0322]

Presidential speed... I like it.

[caseye11is]

that one made sense!

[0xan4xan0]

Ron Paul

[TheQuestion8]

i seriously have homework to do

okay okay one more video

[MegaLalablahblah]

Wait, why would we think of light as a particle? Isn't it massless? Why can't it just take the quick way? I'm really confused.

[JoonasWTF]

@MegaLalablahblah What are you confused about, exactly? Light can behave like a wave and like a particle (wave-particle duality). To explain this particular situation, the particle form of light is needed. Photons have a rest mass of 0. It can't take the quick way, because a photon is the quantum of electromagnetic radiation and thus interacts with charged particles, mainly the electrons orbiting the atoms.

[SystemofaJake1]

32 people never heard of Dark Side of the Moon.

[voodo133]

32 People failed to travel at full Presidential speed

[1pnoe]

0:37 Penis out of ass?

[BillyBobJimJoeJeffJr]

this is educational and hilarious at the same time lol

[truelieswow]

@wormguts he didn't create it, but it's a brilliant analogy all the same

[CoolCat123450]

Presidential speed is light speed.

[Sheriichi]

i still don't get it- is light a wave now or does it behave like particles?

[deesharkz]

@Sheriichi both, light is described having a wave-particle duality.

[MorphinMan33]

@Sheriichi It's a particle directed by a wave, if I am not mistaken.

[JohnSmith88823]

But the room has air, and air causes some resistance. Does that mean that light, without any resistance, can travel infinitely fast?

[farfarawayfromyou]

@JohnSmith88823 no, when light travel in vaccum ("without any resistance "), then it travels at 300 000 000 m/s

[opaldragon75]

this is wrong and so many level... mostly cause it is so close yet just doesn't hit it. If I hadn't seen sixtysymbols's video (youtu.be/Omr0JNyDBI0) I would have not seen the error.

your demo shows a scattering effect on photon paths which would make polish glass a light diffuser.

Every time a photon interact with a atom it gets delayed even if it fails to be adsorbed properly, denser the atoms more the delays per inch.

Why Light bends in glass, not a clue.

[Spazticrhino]

@opaldragon75 Your grammar greatly reduces the efficacy of your argument.

[opaldragon75]

@Spazticrhino Wow a Grammar Nazis! Ya I goofed but Youtube doesn't let me edit my comment after I post it. If youtube had an edit option I would have used it!

But if you wanna judge my validity based on my grammar then you be lumping a lot of other scientist and researcher with me cause a lot of them make mistakes too.

[TakesTwoToTango]

If you like this video, check out information on metamaterials!

Light going through a metamaterial is distorted completely different. It is possible to create true invisibility cloaks with them. Which has already been acheived, but not for the visible spectrum.

Also, just to give a prickling example, if a fish would swim in a pond with a negative refractive index (a metamaterial), then to an observer outside the pond it would appear to swim above the pond.

[GodofReapers]

c is the speed of light IN A VACUUM. This is very important. The speed of light in a vacuum is constant in all reference frames, but in other mediums the speed of light changes.

[TheDarkluster69]

Pink Floyd!!

[Mageorama]

0:04 dark side of the moon?

[cuzco07]

Just like Brian Cox used Margaret Thatcher, years ago, on Ted talks.

[mrtoastystudio]

THUMBS UP IF YOU HEARD THE MUSIC AT 1:07

[higuitacrack]

@wormguts best thing ive ever seen

[CakesnakeFilms]

for the wave model of light he literally said that the reason light slows down in glass is because light slows down in glass

[lk3hjduio]

The explanation in this video is completely wrong.

[emikochan13]

@lk3hjduio please extrapolate.

[theskatmaaan]

@lk3hjduio then explain it to us, don't just put it down

[Krethas]

You make these concepts seem so simple... Why couldn't you have been my physics professor?

[MrJollyvolly]

i think iwe heard that music at the end of the movie in fallout before...

[papagalop]

aahh..mindfuck

[HammerNHook]

So, is light traveling slower through glass as a result of refraction, possibly?

[adaman103]

officially after this video i understand how life and light and everything works!

[coolfelix999]

Great! Now I understand the constant speed of light in every reference frame, even with the effect of refraction! Thanks a lot =)

[thegfguys]

I can understand everything now

[Waluigi71]

Lol I play that President theme song in Band except it has Christmas melodies thrown into it. It's called, "Santa Meets Sousa."

[ceyel6]

i cklicked the video cause i thought it was pink floyd :(

[shiznak55]

great president analogy! lol

[deadturtleproduction]

the president should legaly be required to wear that hat at all times

[TomalvaTech]

Ahh I love minutephysics. Do you guys agree?

[deanman007]

careful Mr president thats a suicide bomber

[callumAS]

This was kind of misleading since light doesn't travel at C in air. Still I loved the president analogy.

[Lulzalutioners]

@callumAS Yeb, they are often over simplified for time purposes. It's a bother.

[samsledje]

I literally fell over laughing when I saw "Door Force One." But I assumed the presidential anology he was going to make was about how light can't be white...

[XxDazedandConfusedx1]

in other words, Pink floyd

[DondeEstaVee]

@XxDazedandConfusedx1 You mean "minus-green" floyd :)

[lu1scantu]

@XxDazedandConfusedx1 no, minus-green floyd

[Yoshiman6464]

@XxDazedandConfusedx1 That's exactly what I was thinking when I saw the Thumbnail. You gotta love the Dark Side of the Moon.

[RioluStefan]

@XxDazedandConfusedx1 wrong! minus green floid

[MrIndieguitar]

-▲=

[akfforever1]

I finally figured out and understood 1 of these videos! Yay

[mhmyup1]

2 months, 6 days, 22 minutes… no sign of a way out these fantastic videos, my homework must miss me.

[Frostbiyt]

Door force one lol

[iGoBarDown9]

Physics test tomorrow ! :O

[ifeelrelaxed]

So what you're saying is I could have skipped physics today and just watched all of these videos and gotten an A-?

[y890x]

now youtube ads are being designed specifically for youtube... i fucking hate ads.

[silicium555]

till 1:05 americans watching this were like: "Whaaaat i have nooooo clueee what the hell this shit is aboooouuut." But THEN Everything was clear :)

[ulkord]

how can light be a wave and particle at the same time

[finalawesome]

im more of a "light is a particle" man myself

[ThePetarski]

"Full presidential speed."

I lol'd.

[RoySchl]

isn't it more like swimming through jello? if it would bump around and scatter it would 1. still be at the normal speed of light, only the way it took got longer and 2. it would not come out straight but in a random direction (each photon) so a more or less straight light beam would come out as a scattered cone

[zoaiquwyetr]

@RoySchl good observation, because this analogy is indeed wrong; it seems that ppl also very often forget that refractive index isnt necessarily greater than one (i.e. light travels in the medium faster than the normal speed of light?), in fact the actual speed of light is the same in either medium, and everything else is lies... or smth like that...

[Dream1nColour]

favouriting for "door force one"

[alan26930]

Lemme say something stupid that most part of the people will understand.

PINK FLOYD

[fatpersononabicyle]

--▲<

minute physics in a nutshell

[GaryMofOak4President]

I learn more from him in 2 minutes than in an entire day in physics class!

[alecazam3567]

Door Force One

[KingQuag]

I watch these videos because the pictures entertain me :3

[cataplunina]

"Good to meet you!" "How are the kids?" "[CLASSIFIED]"

[snipeLAX]

Is it the same for sound waves through water???

[chemicallingo]

@snipeLAX no, because sound waves aren't radiation

[pg6661]

@snipeLAX Not exactly... Sound waves through water are mechanic waves. This means that they need a substance in order to "move" (in this case, the substance is water). On the other hand, light is essentially an electromagnectic wave (an oscilliation of magnetic and electric field...) and such a wave dosen't need a substance in order to move. Light can move across space, water, glass, etc. Sound waves (mechanic waves) cannot move through space (in space (void) there is no 'substance' .

[dimentiosbigfan]

You learn more from this guy in one minute then you do for weeks in school :/

[AtomicPengWIN]

@onemark. I KNOW RIGHT!??!

[seumulhana21]

I feel so smart already LOL!!

[Onemark]

HOLY SHIT IT MAKES SO MUCH SENSE!!! <3

[mooningducky]

Can anyone tell me what grade this so for?

[OhNoApples]

@mooningducky Grade 10 and up Physics (Study of Light)

[GN77340]

Full Speed Mr President

=l:)  <---Tophat and all

[uratoko]

1:05 Fallout 3

[icdalight12345]

haha door force one.

[michiganhoc]

0:44 Look Nyan cat!!!

[25Mexx]

dind not understood anything until 0:55

[ChrisOBrienAcappella]

reminds of Jessie Eisenberg in the social network

[NoHeartNoLove11]

Teehee silly hat

[AnonymousTheHippo]

wait...... im in seventh grade..... y am i watchin this again?????

[skatefdp]

i want to be like you when i grow up



[PSYCHOTICsweed]

i learned in chemistry that light travels through diamond at 33 meters per/s

[GiptoCryptio]

how many black markers have you gone through?

[Raaaaaaaandy7]

I like your references so it dumbs it down for simple people

[comeinwehavecookies]

@Raaaaaaaandy7 like me

[keyblademasterzeke]

28 people didnt get to talk to the president :(

[ReginOlasen]

this guy is a genius !

[MrSonia88]

all about physic :)

[Gh0stBustaz11]

I GET THIS ONE! YES!

[cudionelove]

full presidential speed lololol

[JughedGreenz]

Pres on BOAT "FULL SPEED AHEAD" FTW! 

[iWinFail]

Will you teach me everything now?

[cheasify]

HAHA i GOT IT

[scooterboy012345]

what do you do with all the paper you write on?

[XxDazedandConfusedx1]

pink floyd :D

[ComedianWithTheHat]

Baa?



[mustang6172]

Can light accelerate beyond it's own speed if it crosses the event horizon of a black hole?

[TheRinzl3r]

@mustang6172 Exactly how does that work?

[mustang6172]

@TheRinzl3r As gravity in front of the light would be stronger than energy behind the light, it would not require additional energy to accelerate.

[thesteveoknows]

@mustang6172 Gravity? Seriously? That is so utterly wrong, even though this video doesn't get it quite right, either (with the bouncing between atoms analogy).

[thesteveoknows]

@mustang6172 No, it can't, but if it crosses the event horizon (kind of a fallacy, time stops at the event horizon but black holes grow as they accumulate matter and "swallow" whatever is there anyhow) it can only go towards the center of the black hole and not away from it. The math behind that is really complex, but we did have to prove it once in grad school.

[TheXLAXLimpLungs]

I used to walk at full presidential speed. Then i took an arrow to the knee...

[TheXLAXLimpLungs]

@TheXLAXLimpLungs I used to make arrow to the knee jokes too, but then I got Fus Roh Dah'd

[SimonFanProductions]

Hence, the duality of light. Photons and magnetic fields perpendicular to each other oscillating as a wave through matter :)

[ctech42851]

that was a horiable explanation!

[KevinR242]

Im just a bit confused. but it was cold night. And I have an analogy to boot. It was so cold last night that I froze my balls off. But nature took over and they shrunk up and hid inside me like a woman. Now that the sun is up and things start to warm up my balls have relaxed outside and I am, a man again able to resume my prior abilities like the light wave when it was free of the glass.

[mcnugett]

doesnt make sense, particles have mass. mass cannot travel at the speed of light...

[MrGreekba]

that presedent is white

[DaffyDaffyDaffy33322]

The reason people acually watch these videos is because their more fun than science books :D

[TitoBuzzLoves]

awesome sauce! :D

[disloyalhellboy]

this is gunna help me for my exam, THANKS! :)

[karoscgot]

Precidential speed (y)