Why aren't Mirrors White? Why isn't EVERYTHING a Mirror?

What's the difference between a mirror and a piece of paper? The answer requires an understanding of surface texture, but also light scattering, Huygens principle, and electrical conductivity. Optics is metal!
________________________________
VIDEO ANNOTATIONS/CARDS
The Color White Does NOT Exist:
• The Color White Does N...
You Don't Know How Mirrors Work:
• You Don't Know How Mir...
What the HECK is Energy?
• What the HECK is Energy?
Where Does Light Come From?
• Where Does Light Come ...
________________________________
RELATED KZbin VIDEOS
Vsauce on Mirrors:
• What Color Is A Mirror?
• INSIDE a Spherical Mirror
________________________________
SUPPORT THE SCIENCE ASYLUM
Patreon:
/ scienceasylum
Advanced Theoretical Physics (Paperback):
www.lulu.com/shop/nick-lucid/a...
Advanced Theoretical Physics (eBook):
gumroad.com/l/ubSc
Merchandise:
shop.spreadshirt.com/scienceas...
________________________________
HUGE THANK YOU TO THESE PATRONS
Warden of the Asylum:
YDT
Asylum Counselors:
Matthew O'Connor
Asylum Orderlies:
Daniel Bahr, William Morton, LT MarshMan
Einsteinium Crazies:
Albert B. Cannon, Wacky, Ken Davis, Ilya Yashin, Eoin O'Sullivan
Plutonium Crazies:
JKLMN Anderson, Al Davis, Kevin MacLean
Platinum Crazies:
Mr. Orn Jonasar, Rick Dinning, Eugene Boone, Fletch, Felipe Cruz, Vittorio Monaco, Stephen Blinn, Mikayla Eckel Cifrese
________________________________
OTHER SOURCES
Etymology:
www.etymonline.com/word/specular
www.etymonline.com/word/refle...
Constant Lists:
www.engineeringtoolbox.com/re...
hyperphysics.phy-astr.gsu.edu/...
hypertextbook.com/facts/2004/...
www.engineeringtoolbox.com/pe...
hyperphysics.phy-astr.gsu.edu/...
www.engineeringtoolbox.com/re...
Miscellaneous:
www.koppglass.com/blog/optical...
Optics by Hecht
Electromagnetic Waves and Radiating Systems by Jordan and Balmain
________________________________
LINKS TO COMMENTS
Prompt Questions:
• You Don't Know How Mir...
• The Color White Does N...
• The Color White Does N...
• The Color White Does N...
• The Color White Does N...
Featured Comments:
• You Don't Know How Mir...
• You Don't Know How Mir...
• You Don't Know How Mir...
• You Don't Know How Mir...
________________________________
IMAGE CREDITS
Fluorescence:
www.usgs.gov/media/images/dea...
Phosphorescence:
commons.wikimedia.org/wiki/Fi...
Silver:
www.usgs.gov/media/images/sil...
Mirror Spock:
memory-alpha.fandom.com/wiki/...)

[@WarrenGarabrandt]

In the past few months, this channel has blown away most of the things I thought I knew about how light works. And quantum mechanics. And relativity. Most valuable patreon investment I've ever made.

[@ChrisWalshZX]

Good for you 😁👍

[@swaxtastic]

Same.

[@rogerlow9107]

Thanks to people like you

[@vikranttyagiRN]

Apt to say, you got your priorities right

[@henrybarber288]

Casual flex 😂

[@disregardingsanity7005]

Since the academic year’s done, I didn’t want my grandsons to stop learning. They complained about watching science videos, until they watched yours. They love your content and how it’s presented (seriously, who doesn’t love graphic representations, clones and squirrels?). For four, seven and nine year-olds to enjoy science is a feat unto itself. Your videos are entertaining and definitely informative. Please continue making videos! Thank you.

[@dikshantraj6005]

your videos ask questions that i never knew i wanted, but soon as i see them i get sudden urge to watch the whole video!

[@blueckaym]

Yes, that's one of the unique Nick's specialties :)

[@Fish-ub3wn]

@@blueckaym Called dementation :D (not unique, rather rare)

[@blueckaym]

@@Fish-ub3wn , haha :) ok, I plead guilty of exaggerating a little bit ... but just a little ;)

[@GAURAV_RANA_]

Really? I asked my teachers these things so much they would get angry. This question i asked her and was not satisfied at all. This helped me but after 7 yrs🤣🤣🤣

[@bk-sl8ee]

@@GAURAV_RANA_ that's very true, I can relate to that.

[@buddy5335]

I'm really glad that Nick does all of the Mathematical Doodleedoo's so we don't have to.

[@TheAmbientMage]

"They're going to be the same, aren't they..." The resignation in that statement is palpable. I feel it so much. I love this channel.

[@bk-sl8ee]

Could u explain what it meant I didn't get that sentence that much.

[@Lucky10279]

It's cool how lots of stuff ends being the same thing if you look deep enough -- it means there're all things unexpected relationships just waiting to be found! That's a large part of what makes me love math and physics so much.

[@QDWhite]

These are the answers we deserve but not the ones we thought we needed right now.

[@definesigint2823]

Nicely put :)

[@mjproebstle]

these aren’t the questions you’re looking for... ob1

[@duggydo]

I’ve often speculated about reflection. This video diffused any incorrect assumptions I had.

[@rc5989]

duggydo Ha! Good one!

[@jumpieva]

Thanks for shining light on this subject

[@vomeronasal]

I saw what you did there. Nice 👌

[@MrPinknumber]

Damn, your channel is Gold :D Thank you for these great explanations.

[@markotrieste]

I'd say silver, in this case. Higher plasma frequency :-)

[@JustaReadingguy]

Need to reflect on that comment

[@rizwan4858]

I always wondered about it but now came to know conductivity and reflection are so much connected, You Surprise me every time thank you for your efforts.

[@TheReligiousAtheists]

I got a similar surprise while studying electromagnetism... the relative permeability and relative permittivity of a material have a direct relation with the refractive index of the material.

[@solapowsj25]

Yes, conduction requires there be only one electron in the outer orbital. The stable state of two electrons alternates with one electron during electron-wave passage in current flow. These materials do not allow light to penetrate deep as crystals, plastics and ceramics do. They reflect at the surface with least distortion.

[@huntermoss4587]

I love that you are very connected with the audience!!

[@tom_something]

"The mirror-like reflection in this is from the surface atoms. The color is from the layers underneath." This exhibits an interesting difference between colored metal and polished materials. Plastic, ceramic, and all kinds of other materials will have a diffuse reflection that we identify as the "color" of the material. But the mirror-like reflection is usually neutral. Shine a blue laser on a yellow ceramic plate, and you'll get a good specular reflection of the blue light but poor diffuse reflection. Repeat the same experiment with polished gold, and both the specular and diffuse reflection will be poor. The divergence between specular and diffuse behavior drives our perception of "metallic" vs. "shiny". And the material doesn't have to have a mirror-like finish to exhibit this difference. Some "brushed" gold will still have a very color-biased specular reflection compared to "brushed" yellow plastic. This comes up in 3D modeling, where you can typically set a material's diffuse and specular "colors" separately. For non-metallic items, the specular color is usually set to a neutral shade of gray. For metallic items, the specular color is the same as the color we associate that material with. Though sometimes the color is modified slightly to mimic the way our eyes and real cameras would process it. Of course, when I'm modeling something, they're just values I set without wondering how they work in the real world. As always, this video was very.... illuminating.

[@solapowsj25]

I'd understood that the metal with a single outer electron gives a specular reflection with formation of a virtual image. White porcelain with multiple electrons in it's crystalline surface reflects white with no virtual image, even though it's surface is more smooth. This video makes the point very clear. The blue laser seems too bright and too narrow a frequency range.

[@tom_something]

@@solapowsj25 polished porcelain will reflect a virtual image, but only by a minority of the light. The rest of the light penetrates deeper, where it is absorbed (if dark porcelain) or diffuse-reflected (if brighter). You can see your reflection in a well-polished piece of dark stoneware.

[@nimmen]

It's also why in PBR (physically based rendering), there are so many property maps for example for specularity and metalness. This video made me realise how that connected in the real world. I think the whole idea of PBR is amazing as it makes it possible to measure a surface property and then simulate it, creating a realistic result.

[@tom_something]

@@nimmen Another cool rendering feature I only recently learned about is taking a 360 degree HDR image in a real environment, and then use that image to set all of the lighting for a scene. There's even a polished metal sphere that filmmakers use to grab a quick environment map that will be used to light a 3D model in its place. This way, the light map can be updated with dynamic scene elements, and the ball is sometimes moved around while shooting as well.

[@josephcoon5809]

@@solapowsj25 The thing about metals with a “single outer electron” is that it is a loosely bound electron that all atoms basically share. This is called the conduction band as it requires very little electrical potential to move electrons from one atom to the next. This creates more like a “sea” of free floating electrons. This “sea” has a very high degree of freedom in the plane parallel to the metal’s surface which means any light that is absorbed will move the sea parallel to the surface of the metal far easier than moving it toward or away from the atom. This is most likely why reflected light is polarized parallel to the surface of the material. I would also imagine that this high degree of freedom is also what allows the conduction band electrons to absorb most of the incident light as opposed to insulators absorbing a small portion.

[@jakemoran7118]

Nick coming through with videos on optics as I’m studying for my waves and optics final is a true blessing

[@kateiry4719]

Nobody: Nick: *P E N E T R A T I O N*

[@chuckbucketts]

Nick, your videos often make me feel that there's even more stuff I don't know. They often answer questions I didn't even know I had. Nice work!

[@DarkMage2k]

I never imagined I'd see a dirty joke in such a science oriented channel lol good one

[@jangapardhu5300]

What

[@GMPranav]

^

[@imdawolfman2698]

heh heh he said penetration heh heh, SHUT UP BEAVUS!

[@IshaaqNewton]

Whatever, I don’t think he said a joke. But I liked your joke so much. It was not dirty.😅

[@DarkMage2k]

@@imdawolfman2698 Nah

[@Joyexer]

That was exactly what i thougth would happen, but you took it to the next level with all the details. Thats what makes this channel so special

[@paxdriver]

Everyone dabbling in 3d modelling and texturing (ie blender) should watch your channel for stuff like this! Thanks much

[@bldavis36]

Good video. 2 things though from someone "in the industry." 1), with the actual cost of material (incremental cost) because so little is used, Al and Ag are fairly irrelevant.The primary reason Al is often used instead is because of long term durability. Indeed the price to protect the Ag is more expensive (development and advertising and such) than the actual Ag! And 2, I think that green color at deep reflection may be coming from the typical soda lime glass used in second surface mirrors.

[@radek9616]

First video of yours that I have seen. Instant subscribe. Great content and one of the only youtubers who does not beat around the bush!

[@Danilego]

Wow, this was much more complex than I thought, but still you managed to explain it really well! I remember learning in school about mirrors being smooth while normal materials are rugged, but that wasn't the only part in the equation!

[@stellarfirefly]

Yay, I've been hoping for this episode for awhile now, especially after the previous one. And it was most excellently done, thank you!

[@volbla]

This is, like, everything i ever wanted when it comes to light-matter interactions. Five thumbs up.

[@karthikprabhu3173]

3:52 Seriously I didn't see that coming

[@CJ-111]

This is easily one of my favorite uploaders on KZbin. You have a way of explaining these topics so clearly

[@toanphucnguyentri2896]

As a PhD student in quantum physics, I can only say that this is a seriously good video.

[@CMDR_Analdo_Blackvoid]

I really love this channel. I know of no other place where I can have so much fun and still learn a lot :)

[@definesigint2823]

I had a vague understanding of this ahead of the video, now replaced with the "nice, thank you very much" I so often have after watching. The way you make this approachable casts some light on other things (like the ocean's total internal reflection angle) and fosters further study -- and that's pretty awesome. I hope your subscriber count keeps going in the right direction :)

[@cheeseweasel69]

Another good one Nick! Keep em coming.

[@admiralhyperspace0015]

The summary should have this point as well: 4. It has to reflect back all visible frequencies of light almost equally to not be a distinct colour.

[@ScienceAsylum]

For the reflection to match the color of the object, yes, you are correct.... but I wouldn't have any problem calling a smooth polished plate of gold "a mirror."

[@technicallittlemaster8793]

That was like my whole subtopic of mirror optics in 10 mins for my HS level. You even added some great explanation from graduation level as well Totally loved it. Thanks a lot it really helps my studies and feeds my curiosity. I just can't thank you enough.

[@ScienceAsylum]

Glad you liked it 😊

[@adityachk2002]

Underrated channel.....don't be demotivated your golden day would surely come

[@dtrimm1]

Terrific video Nick - really enjoyed it.

[@deadboy4735]

3:42 Light also goes through the front side and bounces off from the silver with the 2 layers of protective paint on the backside of the mirror.

[@Chad_Thundercock]

3:54 Oh balls, you stole the 'giggity' right out from under me. Well done, sir. Well done indeed.

[@tomaszbekas]

Your videos are amazing! Keep up the good work!

[@NathanPK]

Dude, you get better with every video. Great channel!

[@saatviksinha4881]

You answer common curiosity. Bless you!

[@GameRocker]

Probably the best channel on physics on youtube. I don't know why I found this only a few days earlier.

[@Lucky10279]

I love how you sum everything up at the end of each video. It's really helpful. ;)

[@user-sb3wh3dd4v]

One of your best episodes yet!

[@unvergebeneid]

Me before the video: "Ugh, this is gonna be really basic. I already know this one." Me a few minutes into the video: "nvm"

[@PaulPaulPaulson]

My question is in the video! I'm a question clone now! 😁

[@wolfisr]

Really good explanations about though physics☺ keep up the good work!

[@ChrisWalshZX]

Another EXCELLENT video from Nick. Thanks! 😁

[@kylebowles9820]

In computer graphics we use probability distributions to model how light interacts with different surfaces. We call them BRDFs. My white material always looked a little too glossy, like satin or something... because it doesn't account for the depth and extinction parameters you were talking about! Thanks for the deeper understanding

[@jlpsinde]

Hi, you are very kind to us all e you are the best teacher I know, I am a physics teacher and I didn't learn this things at the university. Amazing work. Perfect. It's a pleasure to help you on Patreon. Feel comfortable to take a rest when you need. We're here for you!

[@ScienceAsylum]

Thanks for the support!

[@chalecoflash]

I still haven't recovered from your previous video about how mirrors work, but thank you for this second jab to the brain :D

[@ScienceAsylum]

You're welcome 😉

[@TheBaltherion]

This guy makes video about questions I never knew I wanted the answer to.

[@kuldeep9605]

I love physics i am in 10th grade i will surly will become a theoretical physicist i am glade i understood nearly 75% of the video so love you sir😊😊

[@Joyexer]

Dont make your mind up too soon. Give all of physics a try and see where it goes. Thoretical stuff is really dry, though sometimes really exciting and mind blowing. Nowadays theoretical physics is really advanced and the experimentalists cant really keep up with all the stuff proposed. So the theorists dont get enougth imput back, as it seems to me at least. Anyways... Keep your mind open and question everything. :) I ll study physics soon as well and will by great chance be an experimentalist. Have a nice day!

[@beachcomber2008]

And don't be surly. :)

[@FriedrichHerschel]

I hope you love math as well then.

[@FreeStuffPlease]

Goodluck with ENC 1101 😄

[@MrGeoffHilton]

You're so brainy, but at the same time totally looney, I love ya!

[@jaunesmith0947]

2:15 I always get pumped when this music starts playing!

[@geoffstrickler]

Good explanation. Best I’ve seen or read on the topic.

[@mohammedal-haddad2652]

I'll never look in the mirror the same way I used to again.

[@mohammedal-haddad2652]

@eatskittensfordinner now I am in a mood for watching Airplane!

[@BCdesu]

1 question here: "Mirror mirror on the wall, who's the best physics KZbinr of them all?" . . . . . . -It's Nick, it must be Nick!

[@onradioactivewaves]

Great job on your videos!

[@danielwalker5682]

Another brilliant set of explanations. Thanks!

[@jacobostholm9030]

its like The Science Asylum reads my mind. Thank you Nick

[@gavin_oppegard]

This actually makes 3D modeling more understandable.

[@RavenLuni]

A subject I know and love (spent alot of years coding ray tracers) and you still covered more than I ever thought of. You rock :)

[@SinanAkkoyun]

I love this explanation! I would have liked to see you explaining the result of electric conductivity in regards to the fresnel effect in metals an dielectrics, but this would have been too much. Love it! Even though this is two years old, I wanted to praise you for your videos!

[@valdemarbndinghansen3109]

I’m gonna have to be that guy and ask: “WHY does higher conductivity mean a lower penetration deapth” And great video as always, made me ask myself a ton of questions, which is always a good thing🙂

[@alexanderofrhodes9622]

Higher conductivity generally means more free flow of electrons in the material, which interferes with the lights ability to penetrate -A guess

[@0x0404]

Polishing to a mirror shine is a term for a reason!

[@brianbushue2997]

dude i am so glad if found your channel. so informative, and fun. this was a great video

[@ScienceAsylum]

Glad you enjoyed it! 🤓

[@anushkapoor676]

One of the best videos on the topic, answered so many questions I had in past...

[@joelcraig9803]

3:51 "Its something we call Penetration Depth" Was that innuendo clone?

[@adam3896]

How do you always manage to get things right. Seriously, a lot of professors are stumped by a fair amount of questions you answer.

[@ScienceAsylum]

I do a lot of research and keep learning. Unfortunately, many professors stop learning after they get their degrees. (As someone with a chronic illness, I can tell you this is true of many doctors too.)

[@mpopa5673]

Another amazing video. Good job !

[@ibanix2]

This dovetailed nicely with my Optics class this semester....

[@joeycook6526]

I caught myself trying to like this video like 5 times after I'd already pressed "like."

[@HelmutPolischer]

He's got me saying "super zoom" before he says it :)

[@lexusmaxus]

So wonderful to see your latest video

[@iamjimgroth]

I love your videos. Even when something seems super simple I end up learning something. :)

[@rhythmmandal3377]

Your vids make me think "should have taken physics in university"

[@davidecarusone3333]

Me before watching the video: I know why white materials aren't mirrors, it's because of the imperfections on the surface! Also me 1 second later: .....that's not the whole story, is it?

[@jimmomusic]

Love your channel! About 15 seconds in, I was thinking "Feynman diagrams would be a cool way to give an intuitive explanation". Get your bongos out! :) haha! Also, your point about green light aligned with something I was telling my eldest about why chloroplasts reflect green light (why are plants green?) because it is the most inefficient wavelength for absorbing energy for photosynthesis...it's no coincidence that plants and recursive mirrors reflect green!

[@thegenxgamerguy6562]

Honestly, I wondered about that, too. Especially after your last mirror video. Thank you for the great explanation!

[@starkillerz6235]

I have a question. Does dissipative absorption result in the frequency of light (colour to us) of an object given off or the reflected light of a mirror? p.s this channel has really inspired me a lot so thank you.

[@ScienceAsylum]

Yes, dissipative absorption is the kind that result in the color we see on objects. The colors (frequencies) near the resonance stay absorbed and the rest are re-transmitted dissipatively.

[@Nulley0]

Meerer is what we like...

[@gabrielkouvalis8621]

I've always wondered why mixed colours reflect a colour that was previously absorbed. This video somewhat lays some ground on why this might occur but I'm still left with questions. Love the vids!

[@Roust7]

Most complete explanation. Well done

[@intotheunknown8100]

That's great informative video.. Thanks

[@kex0]

I was looking for a comprehensive explanation of why light is "bending" when crossing between 2 different mediums for years. This helped me a lot. Thank you.

[@Lucky10279]

Nick: You don't need quantum mechanics for this. Also Nick: shows light as a wave and talks about quantum energy levels. ;)

[@ScienceAsylum]

😂

[@BrianFedirko]

that is amazing, and we walk around not knowing any of this... even though it''s comprehesive. love it! ☮

[@Anoyzify]

This channel is going far, and it deserves it!

[@constpegasus]

Great as usual. These videos never disappoint.

[@nradamson]

"So why aren't all insulators transparent?" By the end, it made sense why a good mirror needs to have a specular surface (that's the one most people discuss), why it needs to be a decent conductor (shallow penetration depth that results in greater reflected light than transmitted light), and not have electron energy levels that match the frequency of incoming light (resonate absorption traps light as heat, whereas dissipative absorption allows it to be released as EM wave patterns that can build up at the angle of reflection)....but I feel like that one question thrown in there wasn't answered. Am I missing something? What causes insulators to be opaque? is that simply a result of the random way the atoms are organized inside that produces constant absorption and emission internally? Does this mean opaque insulators capture more heat as a result if the continued oscillations of these atoms and increased kinetic energy from those oscillations? If not, why doesn't this transmitted light come out the other side of opaque insulators? (Sorry I know this is a long comment but I love your channel and your videos are so enlightening - just trying to wrap my mind around that piece)

[@chiefdvm1671]

Whoa.... I didn't think being a mirror would have so many properties of its own. This video was phenomenal!!! Understood each and everything clearly...! Thank you Nick!

[@earychow839]

I am learning 3D CG and your video make me understand more about those BSDF PBR shaders I have been using. Thank you!

[@ScienceAsylum]

You're welcome! 😊 I have lots of people in the comments saying this and I'm always happy to hear when my videos help.

[@mahxylim7983]

Great video as always!

[@ScienceAsylum]

Thanks! I really like how this one turned out 😊

[@benjaminsharef6589]

Great video--expand a lot about mirrors that I didn't understand.

[@Mr-Garibaldi]

Always enjoy when the music changes into "We're getting Serious" mode 😂... this time at 2:15

[@fdavillar]

That is fantastic, one more reason to join electrical and magnetic fields! GREAT episode. I have a question: Keeping in mind the electrical conductivity, would distilled water have different reflection/refraction properties than salt solution?

[@estebanfm7940]

I have been looking for this information for WEEKS, thank you sooo much for this man, it really helps me because I'm doing an experiment which involves light interactions. For this and your silly humour, you got a new subscriber

[@ScienceAsylum]

Glad I could help! I get a lot of comments on this video from 3D artists who are trying to understand subsurface scattering. Good luck with your experiment!

[@scottmarshall1414]

Awesome! Got a video on dichroic mirrors in the hopper?

[@freespeechisdead1565]

0:08 I love how one of the questions is, "If white color reflects all the light, what a mirror does?"

[@ashsamuel5324]

How are you this good with your video production & story telling? and your a scientist! Thank you for doing this sir!

[@harthur2010]

Love the the cameo by the mirror universe Spock. Awesome!

[@sander_bouwhuis]

Oooooooooooooh, wow! Thank you! The refractive index of light going through different mediums has baffled me for decades! Up to now I only knew about the 'light takes all paths but most strongly at the refractive index' explanation.

[@udokahn3262]

Once again you out did yourself, amazing video keep it up i love it, and you