As a blind person, I truly appreciate when they explain what they are doing in the video, whether it's through the use of their hands or by describing how they are blowing air over a piece of paper. Unfortunately, very few people are aware that blind individuals listen to TH-cam videos, and they often fail to provide sufficient explanations, which can result in me missing out on valuable information. So, thank you again for taking the time to describe your actions and being inclusive.
If you have something or someone to read back to you have you tried to look into elon musk and neura link? Supposed to fix issues I'm not sure about blind but possible actually
I can't get enough of this show. Not only is Neil brilliant but his passion an ability to reach people and explain such complicated topics. Professors need to learn from him.
I wanna thank my high school Physical Science teacher, Mr. Hiott, for this memory: We were learning about basic optics, and he covered reflection and absorption, but I was feeling snarky and said "well what about clear stuff then, huh" He got quiet, looked right at me and said "It *transmits* it" and my jaw dropped lol
@@ModestNeophyte I am sure it said "Physical teacher" and you corrected it. Haha But I don't see the "(edited)" thing your post so may be my late night brain didn't read it correctly. Lol
I loved the talk, but honestly, I was hoping for more insight into the property of transparency itself in terms of the mechanism on a more fundamental level.
I believe that it has to do with the energy of the photons [wavelength] and the energy level of the electrons around the atoms of the material in question. If the photon does not have the right energy level to match the energy needed to bump an electron into a higher energy state, it cannot be absorbed, and it passes through...transparent. If the photon does match an energy level and gets absorbed, not transparent. That electron will then quickly drop back to its previous energy level, emitting a photon at the same energy level, but in a random direction...hence...the colours of objects. Cheers
Well, visual properties of things are based on their surface chemistry. For something to NOT be transparent, means that it absorbs incoming photons, which excite the surface atoms, which then re-emit that light. Based on the amount of energy that photon has when it is re-emitted, that determines what 'colour' we see that object as being. For something to be transparent, it would have to fail to absorb photons. Or at least, it would have to fail to absorb a majority of photons. That's as far as my certainty goes. Beyond that, if you would want to know why 'x' doesn't absorb photons, while 'y' does, it would just be conjecture on my part. My guess would be that the electron structure of the atoms/ molecules/ compounds would have a lot to do with it, with complete orbitals (s/ p/ d/ etc) trending towards transparency, while incomplete orbitals tend to opacity. For example, water has 2 hydrogen atoms with complete (covalent) "S" orbitals and oxygen with a complete "P" orbital. But again, that's just a supposition.
That is why centers of education exist. No need to wait for anyone to explain it. And you'll get much more inclusive information to boot. By its design and function, youtube is unable to provide the entire picture. Get a rough, working idea here, then hit the university for the complete knowledge.
Ta da! :) th-cam.com/video/Omr0JNyDBI0/w-d-xo.html and there's a few other ones in the suggested links and I think veritasium did one too. There's a few bad explanations that are even taught in school but that video sets it straight :)
I'd love to see a part 2 of this that goes into the molecular physics of why some materials (like glass, water, diamonds and some plastics) are transparent to visible light, but almost nothing else.
In Switzerland, you learn all this stuff at the age of five to six in kindergarten. I'm 42 now and clearly remember this. My niece is 9 and my nephew is 7 years old and both know this for years. It is unbelievable to me that a full grown men could not know this basic stuff. All you need to know is the full spectrum of light and what part you can see of it. I was so blessed to grow up in this Country.
Love the show and the topic! 2 basic types of safety glass in the automotive world. Tempered safety glass which breaks into tiny cubes vs sharp shrouds. Typically side and back glasses. Laminated safety glass has a plastic film between 2 sheets of glass. The glass sheets can be tempered or traditional types of glass. Traditional glass + a plastic film is used for windshields. Windshields need to be as clear as possible after a fracture.
I love explaining transparency to people, because they don't realize that the windows in our houses are only transparent to visible light, but then your walls are totally transparent to infrared😂 imagine if we saw the world like that instead, our infrastructure would be very different
@@jewulo Well, as Mr. Tyson has said, a thin glass pane in not transparent to infrared, effectively blocking it... but why would the walls be? Here's a little "scientific" test: try setting one of those heat lamps with hot wires in one room, and get in the adjacent room behind the wall. Do infrared rays still hit and warm you up? Probably not. Or look up, say, pictures of thermal imaging of buildings, used to evaluate thermal insulation efficiency and locate leaks. Doesn't look like "your walls are totally transparent to infrared". No big brain science, really.
11:40 yes, that's why cars are damn hot inside when left in the sun, visible light gets into, warm the interior, the interior radiates infrared but can't escape the same way and get trapped.
If you take what Neil says about glass you can understand how greenhouses work. The glass in a greenhouse is opaque to IR and UV lights, they act like an insulator. But they let visible light in. This visible light has has a lot of energy and can heat up what it hits. This is why cats love lying in sunlight, it’s nice and warm. Well whe something heats up is emits IR light. That reflects off of the glass and back to any surface inside the green house. That is how a greenhouse traps heat in the winter without the need of a heater. Greenhouses let light in but trap the IR from getting back out.
I had a Photography class in Universality. We had a practice where we got to take a series of photos outdoors twice, once with the UV filter and the second without (on analogue reflex camera). After developing the pictures we could compare the 2 shots, the ones without the filter frequently had streaks of light. That was how I learned first hand about UV rays.
14:45 Just as with a mirror! When you place an object under a napkin and press it against the surface, you can see it from the side. The light is curving around it? Or??
Love your work. Tiny mistake though. The windshield in a car is laminated with plastic so that it doesn't break at all. It's the side windows and back windows in cars that are the safety glass that shatters into tiny pieces. 😅
15:19 The James Bond movie in question was Pierce Brosnan's fourth and final 007 movie, Die Another Day (2002). However, the car technically did not "bend" the light around itself. It was a system which had the *effect* of bending the light around the vehicle. As Q (John Cleese) explained it: "Aston Martin call it 'the Vanquish'; we call it 'the Vanish'....Adaptive camouflage. Tiny cameras on all sides project the image *they* see onto a light-emitting polymer skin on the *opposite* side. You see? To the casual eye, it's as good as invisible."
Listening to Neil explain physics is like eating a chocolate covered ice cream cone --- There's always this top layer of knowledge that I can ingest that always delivers yet another layer of enrichment of wisdom. Thank you Neil!!!
Ive tried to find comedy that makes me laugh but cant much that makes me laugh. I need a good laugh with the stress around atm. I decided to click your video as im interested in science. I did not expect to laugh so much and learn at the same time. Loved it.
You should have mentioned the transition from sand to glass and how that process transforms the opacity. ..and other chemical propogations that make other transparent materials. That could be an episode all it's own with a special guest.
Silica is transparent, to begin with. It's impurities, small particle scale, and refraction that make a handful of it seem opaque, along with other materials mixed in the sand, most of which would be filtered (sifted, burned, slagged) out in quality glass making. If you look at silica sand under a microscope, its transparency becomes...clear. Yes, that pun was unavoidable. I would definitely welcome a Star Talk expanding on this and getting into the molecular qualities that make particular materials transparent to particular wavelengths.
@@VoltisArt yeah, maybe recent discoveries (concerning frequency and wavelength in regards to transparencies) will propagate a more informative episode.
I thought you would be talking about transparent animals like Glassfrog, Glasswing butterfly, Barton Springs salamander, and other transparent insects, fish, and crustaceans.
Transparency in physics is a fascinating phenomenon that involves the interaction of light with materials. At the atomic level, transparency occurs when a material’s atomic structure does not absorb or scatter light in the visible spectrum, allowing light to pass through without obstruction. This property is crucial for applications ranging from optics to materials science. Understanding the physics behind transparency could lead to advancements in developing new transparent materials with unique properties. How might our understanding of transparency at the quantum level lead to breakthroughs in fields like photonics or metamaterials?
Some of the most enjoyable bits of Startalk since the beginning of the series, is when Chuck and Neil go off on a tangent inspired by popular films. 😆 Question: in Predator 2 we actually see the predator switching vision modes in his visor and I assume he is actually switching between different wavelengths of light/electromagnetic radiation, until he can detect the humans?
That's exactly what the visor is doing. It was uncommon tech at the time, but now people can buy cameras (including some smart phones) that can switch into other wavelengths for things like night vision. Normal digital cameras can see some infrared, and you can test this by "shooting" a TV remote control at a smartphone's camera. (Press any button, it lights up on screen.) One interesting thing I've seen online (edit: Searched and thought at first glance that it was Reddit, but the site in my search turned out to be flagged as malicious.) is a rainbow shown in three photos, from the same vantage point, in IR, visible light and UV. The surroundings shift a little in highlights but otherwise stay the same. Meanwhile, the band shown is a different size in each photo because rainbows - being made from complete light from the sun - contain the full spectrum including all the light we can't see. Larger wavelengths including infrared, microwave, and radio refract more and make the outside portion of the rainbow. Smaller wavelengths including ultraviolet, x-rays, and gamma refract less and make the inside of the rainbow.
Great talk (as always) : side note 😃 typically windscreen is laminated glass (two layers of glass with a plastic layer in the middle) designed to stay together when broken unlike modern car side windows 'safety glass' which is designed to fragment into thousands of tiny blocks as opposed to jagged shards 😎
Windshield glass will not shatter. The side windows, as well shower glass and sliding glass doors, is tempered and does break into pea size pieces that are generally not sharp enough to cut the skin.
5:19 That's a great point! The way light changes through a medium effects its transparency. FLIR (forward looking infrared) cameras detect changes in temperature compared to the ambient temperature and use a gray scale to show that information (when it's high contrast, it can be set to be white hot or white cold. That means anything that is warmer than the ambient temperature, while in white hot mode, will look white compared to the background and things colder will appear black. So, with FLIR, you body heat will be whitish grey and any metal touching your body, will take your body heat and will appear whiter. So, a police helicopter with FLIR can see if you have a gun tucked under your shirt. Your clothing isn't as warm as the mental or your body, so it's transparent to the camera). When FLIR is aimed at a house, however.... next time you see police helicopter footage, look at the homes. you can't see through the glass. You can see the heat (if someone is home or not) but the glass (im presuming here) seems to change the direction of the IR beam and doesn't appear to let it return to the source. The reason your car gets so hot in the sun....the light gets through the glass but it can't easily escape and sort of bounces around...this appears to be similar with IR, making some materials that are transparent to our eyes, opaque to IR. 🤔
Based on the optical gap of glass, it is supposed to be transparent to IR, but OH radical present in glass network blocks IR. Since visible light can pass through the glass’s optical gap, lower energy IR should be able to pass through it. There are glasses which transmit IR (which are used a windows for IR sensor), but care is taken to remove OH radicals from those glass compositions or we can use quartz windows instead for that purpose. Quartz is pure SiO2, while glass contain network modifiers of SiO2 (such as sodium and calcium compounds), which reduce melting point of SiO2 (which makes glass making process cheaper).
I was hoping he’d explain what makes compounds transparent from a chemical standpoint. WHY is molten sand transparent to light, but a rock isn’t? I assume it has to do with the molecular structure and how the wavelength of the EMR makes it through the structure.
I responded with something that might help you a few minutes ago. It all has to do with the purity of the molten sand used for the glass, and how fast it cools. If it cools quickly it is more transparent, and less dense. It allows the wavelength of visible light to pass through, while denser molecular structures do not allow it to pass through. it is a simple concept, but a vast subject. SIO2 is a tetrahedral molecule and allows more gaps in its structure when solid. I will elaborate, if you ask.
@@Richard-bq3ni Well that would be a third reason I guess. Yes, I imagine some of the visible light will also be absorbed by your skin. As for the main reasons, I believe the following two cover most of it. First, when people say that glass blocks UV light or Infrared (IR), they're missing that these are a range of wavelengths that are not all absorbed equally, if at all. Visible light spans *0.4 - 0.7 microns* while IR goes from *0.8 - 50 microns* or so (I don't know the exact cutoff). There's a refractive index info website that gives you the transmission/absorption spectrum for different materials. If you look up most types of glass, it only blocks the majority of IR from about *2.5+ microns.* Wavelengths below that can travel through the glass still. Water, on the other hand, blocks the majority of IR from *1.4+ microns,* if I recall correctly. So there's a whole range of wavelengths from *1.4 to 2.5 microns* that glass misses but water doesn't. And we are mostly made of water, so I think it's reasonable to think that our skin would also absorb those wavelengths. The second major reason is something called *optical saturation.* When light is absorbed by molecules (or a lattice I guess), it puts them in an excited state. Once in this excited state, the molecules them need to transfer this energy to neighboring molecules to fall to the ground state and absorb more light. For most light intensities, this isn't an issue. However, the sun is *extremely* bright, and bombards glass with very many photons per second. And remember that glass is usually *less than a centimeter thick.* This means you have a huge amount of photons coming through that need to be absorbed by a relatively small number of glass molecules (or lattice). The excited states in the glass I imagine could be easily overwhelmed and saturated so that the rest of the sunlight shines through unimpeded. In fact, I have observed this several times. I have a thermal (IR) camera, and when it is pointed at an object behind glass, you cannot see the object at all because the glass is opaque. However, when I point the IR camera at the sun through a window (and I don't like doing this), the sun shines through the window so brightly that it occasionally leaves a streak in the thermal image! I've also filmed the sun's thermal image through a water bottle, which is several centimeters thick! That surprised me because I wasn't expecting to observe optical saturation even at that level. And note that this IR camera's operational range is 8 to 14 microns, all of which would be ordinarily completely blocked by glass, water, and the vast majority of other solid objects.
It's the fact that glass is opaque to infrared which explains greenhouses. I used to think it was the infrared light passing through the glass that warmed a greenhouse. But it's light passing through glass that warms everything in the greenhouse, and that internal infrared light can't pass back through the glass.
When you get to gels used in stage production and theater lighting, the are opaque to all wavelengths of light except a specific small range, such as a green gel will only permit green light while it is opaque to red and blue.
My question would be: does the silicate (SiO2) itself deflect UV and IR? It appears that a coating must be employed onto the glass to have those properties. Anyone knows some details?
I gave an in depth response to this, but the simple answer is, different wavelengths of light pass easier through or around or are blocked by various mediums because of their wave length. SIO2 is a molecule that is a 3D triangle and depending on how fast or how slowly it is cooled has various densities. Impurities can and will also cause filtering effects. Ask more, and i will go deeper into it, if you like.
As a generalist species (adaptive for different environments) the fact we see visible light might be great. BC light is everywhere. It would either give us to much information or go through solid objects and we to know what we can go through or not. Example is birds with glass doors. Lol
This was a really good explanation of transparency. I would appreciate a video along similar lines that explains reflection. Specifically, we know that certain substances reflect portions of the EM spectrum, but as I understand it, we know no substance that can reflect gamma radiation. What is different about gamma radiation? Other than the fact it gives comic book characters superpowers of course.
1:33 I saw an amazing Imax movie about the oceans as a kid. They showed huge kelp forests swaying in the ocean current.....and from that moment on, that's the only way I can see trees: Swaying in a sea of air. I admit, it makes me claustrophobic at times, especially when it's fire season (this year, the air in my city was the worst on the planet for a few days due to the smoke...and I have asthma, so it was like being in a unclean fishbowl).
Essentially the mesh screen on the microwave oven door is like a 2 way mirror where you the human with visible light can see inside but the microwaves if they were sentient would just see more or less another wall to bounce off of.
The side windows in a car will break into many tiny pieces which are mostly not sharp-for safety. The windshield will not separate into many tiny pieces-again for safety. The windshield has a layer of plastic in it to hold all the pieces together.
Fun fact: the makers of Predator actually had a hard time creating the infrared footage because the very jungles of Mexico (where the filming was done) were so hot that all they got from it was a confusing image of everything glowing. This is closer to the vision revealed the Predator had without his mask on. The jungle had to be artificially cooled around the actors to get the 'thermal image' movie goers became more familiar with.
Safety glass also has a layer of plastic in the center that keeps the shards for the most part in place so the glass dies shatter into small pieces but they also generally stay in place
8:08 "the wavelength of microwaves is like a few mm up to maybe a couple of cm" correct me if I'm wrong but how does the size of the mesh prevents those wavelengths to go through it? Doesn't the size of the mesh have to be smaller than the waves' amplitude rather than its wavelength?
I wonder if this can also make an invisible cloak. The cloak will convert visible light to radio wave when the visible light pass travel from front side to back side and then convert radio wave to visible light when it travel in the from the back side to the front side. So when light from behind you pass thru the cloak it will become radio wave which can travel thru your body and then that radio wave will be convert back to visible light making the other seeing object in your back.
11:34 windows prevents the transmission of heat only if it is a double/triple glazed with vacuum between the 2 layers. And it would still allow the radiant part of the heat to go through it.
Safety glass comes in a few varieties: Laminated (glass,glue film,glass), wire (wire mesh inside glass), heat strengthened/ tempered (the stuff that breaks into millions of pieces).
is it possible that black holes huge objects that have become transparent due to light or other rays bending as it passes them. if so does this mean there are many objects we can't see ?
So how does JWST work... I understand there are mirrors that focus the light, but is there any lenses in use to focus the IR light and if so do they use a glass or material that let's IR through? Also I have an IR filter on my green light laser so I don't fry my eyes by accident and not know it... but would any glass block that laser if it was thick enough?
It would probably depend on impurities in the glass itself. As far as JWST, it uses beryllium flattened down to an insane level then coated in several nanometer layers of gold as far as I know
Mirrors reflect radiation. They are not designed for transparency. They use various detectors in the JWST, once the radiation is in focus. Look up amateur astronomy and get into it, you will learn way more than you are asking about.
@@leeguidry9850 I wasn't good at math until I had a teacher who approached it with more logic and had a better way of explaining it, and all of a sudden it clicked and it all made perfect sense: My grade shot up from a D to an A! Go figure. Of course when I studied electrical engineering it didn't help that I could do the math because I couldn't remember formulas well, and especially all those freaking Greek letters!🤪
this got me thinking about why aliens die at the end of war of the worlds. when the aliens get out of the robot things they all die because of the atmosphere of the earth. i think the reason why this is has nothing to do with how they breathe but its a metaphore for how mysterious dangerous and scary aliens are but when they are exposed to the air which is transparency it all falls flat and nothing really happens.
Bond film is 'tomorrow never dies' ... Seriously though Glass is not all transparent... Mind-blowing stuff... Thanks Dr. Tyson and Chuck nice... Be a glass in your relationship... Nice advice
As a blind person, I truly appreciate when they explain what they are doing in the video, whether it's through the use of their hands or by describing how they are blowing air over a piece of paper. Unfortunately, very few people are aware that blind individuals listen to TH-cam videos, and they often fail to provide sufficient explanations, which can result in me missing out on valuable information. So, thank you again for taking the time to describe your actions and being inclusive.
I hope your reading this....are daredevil powers real?
If you have something or someone to read back to you have you tried to look into elon musk and neura link? Supposed to fix issues I'm not sure about blind but possible actually
Can you please explain as a blind person how you perceive sight and stuff like that? Id find that very interesting, thanks
Hello blind person. 👋✌🍭
Ps: you mis-spelled "either"
I can't get enough of this show. Not only is Neil brilliant but his passion an ability to reach people and explain such complicated topics. Professors need to learn from him.
I wanna thank my high school Physical Science teacher, Mr. Hiott, for this memory: We were learning about basic optics, and he covered reflection and absorption, but I was feeling snarky and said "well what about clear stuff then, huh" He got quiet, looked right at me and said "It *transmits* it" and my jaw dropped lol
Physical teacher?
@@sureshkrjsl ?
@@sureshkrjsl "Physical Sciences" are the studies of inorganic matter. Anything that is not alive.
@@ModestNeophyte I am sure it said "Physical teacher" and you corrected it. Haha
But I don't see the "(edited)" thing your post so may be my late night brain didn't read it correctly. Lol
I loved the talk, but honestly, I was hoping for more insight into the property of transparency itself in terms of the mechanism on a more fundamental level.
Didn't get a chance with Chuck's jokes and tangents taking up 80% of the video! 😅
I believe that it has to do with the energy of the photons [wavelength] and the energy level of the electrons around the atoms of the material in question. If the photon does not have the right energy level to match the energy needed to bump an electron into a higher energy state, it cannot be absorbed, and it passes through...transparent. If the photon does match an energy level and gets absorbed, not transparent. That electron will then quickly drop back to its previous energy level, emitting a photon at the same energy level, but in a random direction...hence...the colours of objects. Cheers
Well, visual properties of things are based on their surface chemistry. For something to NOT be transparent, means that it absorbs incoming photons, which excite the surface atoms, which then re-emit that light. Based on the amount of energy that photon has when it is re-emitted, that determines what 'colour' we see that object as being.
For something to be transparent, it would have to fail to absorb photons. Or at least, it would have to fail to absorb a majority of photons.
That's as far as my certainty goes. Beyond that, if you would want to know why 'x' doesn't absorb photons, while 'y' does, it would just be conjecture on my part. My guess would be that the electron structure of the atoms/ molecules/ compounds would have a lot to do with it, with complete orbitals (s/ p/ d/ etc) trending towards transparency, while incomplete orbitals tend to opacity. For example, water has 2 hydrogen atoms with complete (covalent) "S" orbitals and oxygen with a complete "P" orbital. But again, that's just a supposition.
That is why centers of education exist. No need to wait for anyone to explain it. And you'll get much more inclusive information to boot.
By its design and function, youtube is unable to provide the entire picture. Get a rough, working idea here, then hit the university for the complete knowledge.
Ta da! :) th-cam.com/video/Omr0JNyDBI0/w-d-xo.html and there's a few other ones in the suggested links and I think veritasium did one too. There's a few bad explanations that are even taught in school but that video sets it straight :)
I'd love to see a part 2 of this that goes into the molecular physics of why some materials (like glass, water, diamonds and some plastics) are transparent to visible light, but almost nothing else.
Right?? Why can we manufacture transparent plastic bottles etc but not transparent metal?
@@markthomas6045 transparent aluminum exists
That's why I watched the video... disappointed again. Gotta stop watching these vids!
Please do this!
@@laxnkid22on star trek
In Switzerland, you learn all this stuff at the age of five to six in kindergarten. I'm 42 now and clearly remember this.
My niece is 9 and my nephew is 7 years old and both know this for years.
It is unbelievable to me that a full grown men could not know this basic stuff. All you need to know is the full spectrum of light and what part you can see of it.
I was so blessed to grow up in this Country.
You rock Chuck and Neil !! I haven't missed a show in over a year now. Thanks Guys
As it should be. ;-P
I love Chuck's tangents which turn a 5 minute video into 20 minutes.
I will never miss an episode of StarTalk!
As it should be. ;-P
Expecially with chuck to know how to carefully lie through your teeth
PREACH! (Nice username, B.T.W).
@@nerd9347. Thanks!
@@Life_42 No prob! We’re you referring to the book, or the movie adaptation?
😂😂😂 I could watch Neil and Chuck all day!!
Love the show and the topic! 2 basic types of safety glass in the automotive world. Tempered safety glass which breaks into tiny cubes vs sharp shrouds. Typically side and back glasses. Laminated safety glass has a plastic film between 2 sheets of glass. The glass sheets can be tempered or traditional types of glass. Traditional glass + a plastic film is used for windshields. Windshields need to be as clear as possible after a fracture.
It's our favorite personal astrophysicist ❤
You guys are great, love listening to you and Chuck.Thank you.
I love explaining transparency to people, because they don't realize that the windows in our houses are only transparent to visible light, but then your walls are totally transparent to infrared😂 imagine if we saw the world like that instead, our infrastructure would be very different
They are not
🤯
@@bloodgulchpatrick Could you please explain for us non-technically and non-scientifically gifted.
@@jewulo Well, as Mr. Tyson has said, a thin glass pane in not transparent to infrared, effectively blocking it... but why would the walls be?
Here's a little "scientific" test: try setting one of those heat lamps with hot wires in one room, and get in the adjacent room behind the wall. Do infrared rays still hit and warm you up? Probably not. Or look up, say, pictures of thermal imaging of buildings, used to evaluate thermal insulation efficiency and locate leaks. Doesn't look like "your walls are totally transparent to infrared".
No big brain science, really.
Walls are transparent to radio waves, not infrared. In fact, they are completely opaque to infrared.
The mixture of Chucks comedy and Neils explaing is always so delightful 🖤🙏
I couldn't agree more. Chuck's hilarious!
Ah, but " that same guy" was gold! 🤣🤣🤣🤣🤣
I'll say it before and I've said it again:
Neil to reason, but do so with a Chuckle 👍
Chuck is the GOAT
This is one of the best of the best ones ever. Keep it up, guys.
11:40 yes, that's why cars are damn hot inside when left in the sun, visible light gets into, warm the interior, the interior radiates infrared but can't escape the same way and get trapped.
If you take what Neil says about glass you can understand how greenhouses work. The glass in a greenhouse is opaque to IR and UV lights, they act like an insulator. But they let visible light in. This visible light has has a lot of energy and can heat up what it hits. This is why cats love lying in sunlight, it’s nice and warm. Well whe something heats up is emits IR light. That reflects off of the glass and back to any surface inside the green house. That is how a greenhouse traps heat in the winter without the need of a heater. Greenhouses let light in but trap the IR from getting back out.
Neil 'Smoke deGrasse' Tyson is an absolute legend! Wish I had him teaching me at school.
I had a Photography class in Universality. We had a practice where we got to take a series of photos outdoors twice, once with the UV filter and the second without (on analogue reflex camera). After developing the pictures we could compare the 2 shots, the ones without the filter frequently had streaks of light. That was how I learned first hand about UV rays.
14:45 Just as with a mirror! When you place an object under a napkin and press it against the surface, you can see it from the side. The light is curving around it? Or??
I love you two! So funny, entertaining and informative. This channel has it all ❤
Love your work. Tiny mistake though. The windshield in a car is laminated with plastic so that it doesn't break at all. It's the side windows and back windows in cars that are the safety glass that shatters into tiny pieces. 😅
Neil, Chuck and Gerald (Chuck's personal timekeeper).
I love these... It's educational, funny, and built on straight facts. Thanks for being authentic
I love Explainers, wasn't expecting to hear about the Predator, that was hilarious! Mr Nice and Dr Tyson are a wonderful team
15:19 The James Bond movie in question was Pierce Brosnan's fourth and final 007 movie, Die Another Day (2002). However, the car technically did not "bend" the light around itself. It was a system which had the *effect* of bending the light around the vehicle. As Q (John Cleese) explained it:
"Aston Martin call it 'the Vanquish'; we call it 'the Vanish'....Adaptive camouflage. Tiny cameras on all sides project the image *they* see onto a light-emitting polymer skin on the *opposite* side. You see? To the casual eye, it's as good as invisible."
Listening to Neil explain physics is like eating a chocolate covered ice cream cone ---
There's always this top layer of knowledge that I can ingest that always delivers yet another layer of enrichment of wisdom.
Thank you Neil!!!
Ive tried to find comedy that makes me laugh but cant much that makes me laugh. I need a good laugh with the stress around atm.
I decided to click your video as im interested in science. I did not expect to laugh so much and learn at the same time. Loved it.
You should have mentioned the transition from sand to glass and how that process transforms the opacity.
..and other chemical propogations that make other transparent materials.
That could be an episode all it's own with a special guest.
Silica is transparent, to begin with. It's impurities, small particle scale, and refraction that make a handful of it seem opaque, along with other materials mixed in the sand, most of which would be filtered (sifted, burned, slagged) out in quality glass making. If you look at silica sand under a microscope, its transparency becomes...clear. Yes, that pun was unavoidable.
I would definitely welcome a Star Talk expanding on this and getting into the molecular qualities that make particular materials transparent to particular wavelengths.
@@VoltisArt yeah, maybe recent discoveries (concerning frequency and wavelength in regards to transparencies) will propagate a more informative episode.
I thought you would be talking about transparent animals like Glassfrog, Glasswing butterfly, Barton Springs salamander, and other transparent insects, fish, and crustaceans.
Transparency in physics is a fascinating phenomenon that involves the interaction of light with materials. At the atomic level, transparency occurs when a material’s atomic structure does not absorb or scatter light in the visible spectrum, allowing light to pass through without obstruction. This property is crucial for applications ranging from optics to materials science. Understanding the physics behind transparency could lead to advancements in developing new transparent materials with unique properties. How might our understanding of transparency at the quantum level lead to breakthroughs in fields like photonics or metamaterials?
I'm a glassblower.
It's always fascinating hearing more science about this amazing material. Thanks for the prez!
Chuck you are 'OUR' personal comedian. And between both Mr Degrass Tyson and yourself , you are educating us.
Thanks Chuck for the Predator spoilers...😂
Pretty sure AM goes out in tunnels, whereas FM stays
Yep, he got that backwards.
Heck, AM fades under bridges.
Entertainment and knowledge, this is a win win.
Ohhhh exciting. A new one
Some of the most enjoyable bits of Startalk since the beginning of the series, is when Chuck and Neil go off on a tangent inspired by popular films. 😆
Question: in Predator 2 we actually see the predator switching vision modes in his visor and I assume he is actually switching between different wavelengths of light/electromagnetic radiation, until he can detect the humans?
That's exactly what the visor is doing. It was uncommon tech at the time, but now people can buy cameras (including some smart phones) that can switch into other wavelengths for things like night vision. Normal digital cameras can see some infrared, and you can test this by "shooting" a TV remote control at a smartphone's camera. (Press any button, it lights up on screen.)
One interesting thing I've seen online (edit: Searched and thought at first glance that it was Reddit, but the site in my search turned out to be flagged as malicious.) is a rainbow shown in three photos, from the same vantage point, in IR, visible light and UV. The surroundings shift a little in highlights but otherwise stay the same. Meanwhile, the band shown is a different size in each photo because rainbows - being made from complete light from the sun - contain the full spectrum including all the light we can't see.
Larger wavelengths including infrared, microwave, and radio refract more and make the outside portion of the rainbow. Smaller wavelengths including ultraviolet, x-rays, and gamma refract less and make the inside of the rainbow.
Very interesting
Neil & chuck follow up with polarization please!
Wonderful explanation. Now. any idea as to the "why" certain materials are "transparent".... such as glass is to visible light?
Great talk (as always) : side note 😃 typically windscreen is laminated glass (two layers of glass with a plastic layer in the middle) designed to stay together when broken unlike modern car side windows 'safety glass' which is designed to fragment into thousands of tiny blocks as opposed to jagged shards 😎
Thank you! That matches my understanding and recollection. Now I don’t have to spend another 1/2 hour or 5 re-researching that!
Windshield glass will not shatter. The side windows, as well shower glass and sliding glass doors, is tempered and does break into pea size pieces that are generally not sharp enough to cut the skin.
came for the science, but left with sage marital advice. Thank you Chuck!
Can’t believe how many “Wow, really?!” moments are packed in this episode. Thanks guys!
Thank you so much
5:19 That's a great point! The way light changes through a medium effects its transparency. FLIR (forward looking infrared) cameras detect changes in temperature compared to the ambient temperature and use a gray scale to show that information (when it's high contrast, it can be set to be white hot or white cold. That means anything that is warmer than the ambient temperature, while in white hot mode, will look white compared to the background and things colder will appear black. So, with FLIR, you body heat will be whitish grey and any metal touching your body, will take your body heat and will appear whiter. So, a police helicopter with FLIR can see if you have a gun tucked under your shirt. Your clothing isn't as warm as the mental or your body, so it's transparent to the camera).
When FLIR is aimed at a house, however.... next time you see police helicopter footage, look at the homes. you can't see through the glass. You can see the heat (if someone is home or not) but the glass (im presuming here) seems to change the direction of the IR beam and doesn't appear to let it return to the source.
The reason your car gets so hot in the sun....the light gets through the glass but it can't easily escape and sort of bounces around...this appears to be similar with IR, making some materials that are transparent to our eyes, opaque to IR. 🤔
11:05 Hey! ....I actually *knew* something! Wow....this is a first for me!
I wish my teachers had been as good as you. Excellent, always.
Based on the optical gap of glass, it is supposed to be transparent to IR, but OH radical present in glass network blocks IR. Since visible light can pass through the glass’s optical gap, lower energy IR should be able to pass through it. There are glasses which transmit IR (which are used a windows for IR sensor), but care is taken to remove OH radicals from those glass compositions or we can use quartz windows instead for that purpose. Quartz is pure SiO2, while glass contain network modifiers of SiO2 (such as sodium and calcium compounds), which reduce melting point of SiO2 (which makes glass making process cheaper).
One of the funniest star talks i have seen
I love watching these videos. Funny and informative.
I was hoping he’d explain what makes compounds transparent from a chemical standpoint. WHY is molten sand transparent to light, but a rock isn’t? I assume it has to do with the molecular structure and how the wavelength of the EMR makes it through the structure.
I responded with something that might help you a few minutes ago. It all has to do with the purity of the molten sand used for the glass, and how fast it cools. If it cools quickly it is more transparent, and less dense. It allows the wavelength of visible light to pass through, while denser molecular structures do not allow it to pass through. it is a simple concept, but a vast subject. SIO2 is a tetrahedral molecule and allows more gaps in its structure when solid. I will elaborate, if you ask.
Now we need an explainer as to why glass blocks infra-red but doesn't block "heat" at all.
@Paul McMaster What do you mean?
@@DANGJOS You can feel the heat of the sun if you're behind a window, perhaps that is what he means.
@@Richard-bq3ni I had a feeling that's what he meant, but I wanted to confirm. I have a possible explanation for that phenomenon. Well, two really.
@@DANGJOS Please, I would like to hear. Guess some of it is visible light that also converts to heat, correct?
@@Richard-bq3ni Well that would be a third reason I guess. Yes, I imagine some of the visible light will also be absorbed by your skin. As for the main reasons, I believe the following two cover most of it. First, when people say that glass blocks UV light or Infrared (IR), they're missing that these are a range of wavelengths that are not all absorbed equally, if at all. Visible light spans *0.4 - 0.7 microns* while IR goes from *0.8 - 50 microns* or so (I don't know the exact cutoff). There's a refractive index info website that gives you the transmission/absorption spectrum for different materials. If you look up most types of glass, it only blocks the majority of IR from about *2.5+ microns.* Wavelengths below that can travel through the glass still. Water, on the other hand, blocks the majority of IR from *1.4+ microns,* if I recall correctly. So there's a whole range of wavelengths from *1.4 to 2.5 microns* that glass misses but water doesn't. And we are mostly made of water, so I think it's reasonable to think that our skin would also absorb those wavelengths.
The second major reason is something called *optical saturation.* When light is absorbed by molecules (or a lattice I guess), it puts them in an excited state. Once in this excited state, the molecules them need to transfer this energy to neighboring molecules to fall to the ground state and absorb more light. For most light intensities, this isn't an issue. However, the sun is *extremely* bright, and bombards glass with very many photons per second. And remember that glass is usually *less than a centimeter thick.* This means you have a huge amount of photons coming through that need to be absorbed by a relatively small number of glass molecules (or lattice). The excited states in the glass I imagine could be easily overwhelmed and saturated so that the rest of the sunlight shines through unimpeded.
In fact, I have observed this several times. I have a thermal (IR) camera, and when it is pointed at an object behind glass, you cannot see the object at all because the glass is opaque. However, when I point the IR camera at the sun through a window (and I don't like doing this), the sun shines through the window so brightly that it occasionally leaves a streak in the thermal image! I've also filmed the sun's thermal image through a water bottle, which is several centimeters thick! That surprised me because I wasn't expecting to observe optical saturation even at that level. And note that this IR camera's operational range is 8 to 14 microns, all of which would be ordinarily completely blocked by glass, water, and the vast majority of other solid objects.
It's the fact that glass is opaque to infrared which explains greenhouses. I used to think it was the infrared light passing through the glass that warmed a greenhouse. But it's light passing through glass that warms everything in the greenhouse, and that internal infrared light can't pass back through the glass.
👍
Thanks for explaining transparency... I would like to be able to explain things this clear (pun intended)
When you get to gels used in stage production and theater lighting, the are opaque to all wavelengths of light except a specific small range, such as a green gel will only permit green light while it is opaque to red and blue.
I've witnessed a green rim on Barbados sunsets viewed from the sea. Stunning.
My question would be: does the silicate (SiO2) itself deflect UV and IR? It appears that a coating must be employed onto the glass to have those properties. Anyone knows some details?
I gave an in depth response to this, but the simple answer is, different wavelengths of light pass easier through or around or are blocked by various mediums because of their wave length. SIO2 is a molecule that is a 3D triangle and depending on how fast or how slowly it is cooled has various densities. Impurities can and will also cause filtering effects. Ask more, and i will go deeper into it, if you like.
@@jamiboothe yes please elaborate!
3:36 As someone who made a stink about Cameron's night sky, you'd think NDT would make sure his editor knows to have Earth flipped the correct way. 😅💛
0:03 When Neil said -
"Chuck I got another one for you okay,
okay it's transparency."
Best answer could've been. 'I didn't see that coming'
As a generalist species (adaptive for different environments) the fact we see visible light might be great. BC light is everywhere. It would either give us to much information or go through solid objects and we to know what we can go through or not. Example is birds with glass doors. Lol
What about the humans and glass doors?
This was a really good explanation of transparency. I would appreciate a video along similar lines that explains reflection. Specifically, we know that certain substances reflect portions of the EM spectrum, but as I understand it, we know no substance that can reflect gamma radiation. What is different about gamma radiation? Other than the fact it gives comic book characters superpowers of course.
16:05 Right on, Lord Nice. Right on.
Cool, super interesting. But how does sand, quartz, silica which is opaque become transparent as its heated?
Save Dr. Neil at all cost. He is the only one we all need❤.
1:33 I saw an amazing Imax movie about the oceans as a kid. They showed huge kelp forests swaying in the ocean current.....and from that moment on, that's the only way I can see trees: Swaying in a sea of air. I admit, it makes me claustrophobic at times, especially when it's fire season (this year, the air in my city was the worst on the planet for a few days due to the smoke...and I have asthma, so it was like being in a unclean fishbowl).
1:54. Chuck's face when listening about transparency of air. Fml, I was crying laughing.
I'm a glass artist... it's almost as sketchy as water. I love the stuff!
Such a great episode! Had a great laugh at the preditor tangent.
Wow, just wow...this was really interesting!
Thenx mr DNT for shering the way you thinging.
What an interesting subject. Talking about transparency. How can people see ghosts if they're ghost ?
Super interesting content today... 👍🏼
Essentially the mesh screen on the microwave oven door is like a 2 way mirror where you the human with visible light can see inside but the microwaves if they were sentient would just see more or less another wall to bounce off of.
I'm surprised they didn't mention that the predator also has a transparent tech suit.
Fun trick with this video: try moving the thumbnail back and forth up and down, this plays with our perception of motion and technology
It's compressed learning,
The side windows in a car will break into many tiny pieces which are mostly not sharp-for safety. The windshield will not separate into many tiny pieces-again for safety. The windshield has a layer of plastic in it to hold all the pieces together.
Fun fact: the makers of Predator actually had a hard time creating the infrared footage because the very jungles of Mexico (where the filming was done) were so hot that all they got from it was a confusing image of everything glowing. This is closer to the vision revealed the Predator had without his mask on.
The jungle had to be artificially cooled around the actors to get the 'thermal image' movie goers became more familiar with.
Safety glass also has a layer of plastic in the center that keeps the shards for the most part in place so the glass dies shatter into small pieces but they also generally stay in place
These guys are so precious ❤️
8:08 "the wavelength of microwaves is like a few mm up to maybe a couple of cm" correct me if I'm wrong but how does the size of the mesh prevents those wavelengths to go through it? Doesn't the size of the mesh have to be smaller than the waves' amplitude rather than its wavelength?
I wonder if this can also make an invisible cloak. The cloak will convert visible light to radio wave when the visible light pass travel from front side to back side and then convert radio wave to visible light when it travel in the from the back side to the front side. So when light from behind you pass thru the cloak it will become radio wave which can travel thru your body and then that radio wave will be convert back to visible light making the other seeing object in your back.
11:34 windows prevents the transmission of heat only if it is a double/triple glazed with vacuum between the 2 layers. And it would still allow the radiant part of the heat to go through it.
Thank u guys!
Safety glass comes in a few varieties:
Laminated (glass,glue film,glass), wire (wire mesh inside glass), heat strengthened/ tempered (the stuff that breaks into millions of pieces).
is it possible that black holes huge objects that have become transparent due to light or other rays bending as it passes them. if so does this mean there are many objects we can't see ?
Great edits!
good subject, thx guys
So how does JWST work... I understand there are mirrors that focus the light, but is there any lenses in use to focus the IR light and if so do they use a glass or material that let's IR through? Also I have an IR filter on my green light laser so I don't fry my eyes by accident and not know it... but would any glass block that laser if it was thick enough?
It would probably depend on impurities in the glass itself. As far as JWST, it uses beryllium flattened down to an insane level then coated in several nanometer layers of gold as far as I know
Mirrors reflect radiation. They are not designed for transparency. They use various detectors in the JWST, once the radiation is in focus. Look up amateur astronomy and get into it, you will learn way more than you are asking about.
Loving your podcast. Could you do a segment on quantum foam?
I wish you mentioned X-rays as well
Cathode and anode with a grill between can determine electron flow and may be a way to bend light? What materials are opaque? Obsidian?
I love you guys!! The banter is the best….. laughing every time !! AAAAAND of course the information is fantastic and I alway learn sooo much !! ❤😂
These guys are both really funny and smart. Bravo.
I'm glad you introduced yourself as," my personal
Astrophysicist"😊
You have no idea how long I've been looking. 🤔👍
Why or how transparent things are transparent?
the distance between the molecules, and the wavelength of the radiation. There is little more to it than that.
If y’all would have taught me physics in high school I would have been a theoretical physicist. You two make it enjoyable
Til they got to all the math problems...
I got really lucky with that for a few years at least, and had a teacher so animated and engaging I could have had physics classes all day, every day!
@@Bob-of-Zoid physics is the only class I ever got a F for a semester bc my teacher was horrible
@@leeguidry9850 I wasn't good at math until I had a teacher who approached it with more logic and had a better way of explaining it, and all of a sudden it clicked and it all made perfect sense: My grade shot up from a D to an A! Go figure. Of course when I studied electrical engineering it didn't help that I could do the math because I couldn't remember formulas well, and especially all those freaking Greek letters!🤪
this got me thinking about why aliens die at the end of war of the worlds. when the aliens get out of the robot things they all die because of the atmosphere of the earth. i think the reason why this is has nothing to do with how they breathe but its a metaphore for how mysterious dangerous and scary aliens are but when they are exposed to the air which is transparency it all falls flat and nothing really happens.
Chuck had some great points
Bond film is 'tomorrow never dies' ... Seriously though Glass is not all transparent... Mind-blowing stuff... Thanks Dr. Tyson and Chuck nice... Be a glass in your relationship... Nice advice