The lens on my welding helmet was gold. It reflected and absorbed enough of the light to prevent eye damage, but allowed just enough light through to see my work without striking an arc. It was especially good for looking at the sun during an eclipse.
How can Action Lab be so consistently fascinating for so long? I love this guy. It's amazing that I get astonished every time I watch a video here, and this, once again, blew my mind so hard. Thank you so much for sharing these superb insights from nature itself. Please continue for good, humanity needs heroes like this.
I know many people are scared of physics classes because of the math. However, if we could get people just take a year of high school physics, you'd be surprised how the world opens up to you. It's not just about learning "how things work," it's also about learning to ask questions and then looking for the answers. I can look at anything in my office right now and find an interesting physics question about it that applies to the real world. I like science fiction, but the real world has so many crazy dynamics to it. Some of the demonstrations he does are classic physics examples, but he does a great job explaining it. And he comes up with demonstrations I've never seen before.
I never seen anyone shine light through gold leaf before! Quite an extra treat to see for sure in addition to the weird properties of germanium in the long-wave infrared!
@@thaphreak not everyone is curious enough to stumble onto things like this. It's a shame and one of the consequences of a standardized education where exploration isn't encouraged over regurgitation of just the info you're given and nothing more.
@@brfisher1123 it may not have been a demonstration. Sometimes kids just hold something up to see how it acts with the light. None of my science classes ever involved gold leaf, but I found this property elsewhere in metallic films, like the ones signs are made from and some parts of toys with metalized clear plastic.
One of the neat things about gold is that it's particularly good at reflecting IR radiation, so for EVA suits and the helmets used in the moon landings, their visors are coated with a very thin layer of gold to more effectively protect them from the unabated IR radiation of direct sunlight without an atmosphere.
@@GeoffryGifari I mean, the reflectivity of all metals differs on the frequencies involved. Gold just on its own is good at reflecting infrared light, which is why the James Webb Space Telecope uses a gold coating for its focusing mirrors since other materials would absorb a higher portion of the deep infrared-shifted light they designed it to observe.
Many metallic films are mildly transparent. That includes mirrors, which are usually painted on the back for both durability and opaqueness. I used to make signs, and most of our gold or silver-colored adhesive films would let enough light through that you could read a newspaper through them, or use as a rudimentary one-way mirror when the other side was well-lit. (Not requiring a flashlight that rivals the sun...) That includes the "metal-flake" style films, as well as the flat/mirror. I believe most of them were also considerably cheaper than gold leaf.
Hi, I really like your channel. However, this time there is a mistake. Germanium is not a metal. It is a semiconductor meaning that its electrons are bound and cannot move freely. Only when the light photon energy exceeds the binding energy (also called the band gap), the electrons become free. The band gap of germanium is in the near-infrared range. Therefore, the visible light gets absorbed/reflected and the thermal mid-infrared light passes through. Although germanium looks like a metal, its mechanical properties are similar to insulators - it is brittle and cannot be forged like metals. The glass in turn is mirror-like in infrared since its ions oscillate in the light field and act similar to free electrons in metals. Germanium and silicon are non-polar - they don't have positive and negative ions. So they are transparent in the whole infrared range. This is a great advantage and the most of infrared optics is made out of germanium or silicon.
@alexejpashkin3562 Once he showed the IR light shining through, I knew he had a semiconductor. However, I don't think *"The glass in turn is mirror-like in infrared since its ions oscillate in the light field and act similar to free electrons in metals."* is a correct explanation. One, glass doesn't act like a mirror in the infrared anymore than visible light does. Glass actually absorbs infrared light. And I could be wrong, but I always assumed this absorption was mediated via phonon modes, not ion oscillations. But now I need to look it up and get back on that.
(0:50) *Now, just so you don't think this is normal, to be able to see through something with infrared light* I'm glad you pointed that out. Movies and TV dramas tend to have unrealistic portrayals of using infrared cameras to see through walls or ceilings.
I'm trying to do the math on how much gold is in a golden apple vs how much he consumed. a golden apple has 17 metric tonnes and one gold leaf is about 18 mg. let's assume he consumed 1/8th of an apple. if he consumed one eighth of a golden apple in minecraft he'd get about 0.63 seconds of regen and 15 seconds of absorption if the effects translated to real life 18 milligrams of gold would give.... idk a couple nanoseconds probably. I tried to do the math but failed.
This is why germanium is used for the lenses of thermal optics. Thermal optics operate in the far IR spectrum and glass blocks it, so germanium has to be used. It's one of the reasons thermal optics are expensive. Glass will, however allow near IR through, so it's suitable as lenses on night vision optics that operate in that spectrum (i.e. digital IR night vision). Thermal is passive and does not require an active light source (far IR is "heat"). Near IR devices require active emitters (IR lights) to "see" in total darkness.
I like to see your thought process. You first made a video about laser metal cutting, and then you wondered if red hot metals can reflect light or not, and now you are working on light penetration in metals. You are personally educating yourself and also make all of these processes available for us, viewers. Keep up with good work. And for the next video, i would like to see if electrical current or static charges would effect the reflection properties or not (because you mentioned that those properties are strongly related to free electrons and their specs).
@@jeanrenaudsagswing I always thought that was because the tiny holes which carry the information. But the metal could also be see through I learned today ;-)
the gold "filter" looking greenish makes it look perfect as an in-camera nightvision effect! I imagine this would be a cool filter to use in photography or hobby filmmaking
@@DonariaRegia You are thinking of Neutrinos Cosmic Rays are atomic nuclei that move at a high %C and are mostly stopped by the upper atmosphere. They are working on using this decay to take deep scans of things using the produced Muons.
Wouldn't higher frequency light be more inclined to be absorbed, because they have energy for the electrons to be excited? Or is there some new effect at high frequencies?
It's often referencing the emission source of the high energy photon: from a nuclear transition (gamma) or an atomic one. There are actually some nuclear energy transitions in Thorium that result in a 149.7nm gamma ray photon out. Relatively low energy.
Thanks again for a most informative and educational video! It's interesting how materials can be be invisible to certain wavelengths of electromagnetic energy. Your video from about two years ago on making transparent metals was interesting too. And for those who didn't know, astronaut helmets have a gold layer as well which is used to block the sun's intense unfiltered light while in space.
In the entire Elements table, is there this one and only one metal that does this? Is it maybe the very only (in solid state) element that does this? Blocking visible light, but letting through infrared. What an odd characteristic. First time I ever hear about this. As always, great video! And thanks much for sharing these fascinating oddities!
I know many people are scared of physics classes because of the math. However, if we could get people just take a year of high school physics, you'd be surprised how the world opens up to you. It's not just about learning "how things work," it's also about learning to ask questions and then looking for the answers. I can look at anything in my office right now and find an interesting physics question about it that applies to the real world. I like science fiction, but the real world has so many crazy dynamics to it. Some of the demonstrations he does are classic physics examples, but he does a great job explaining it. And he comes up with demonstrations I've never seen before.
The problem is the formal education side requires the math… I was interested in meteorology as a kid, but struggled with advanced math equations so I gave up on that dream. As an adult, I’ve watched many physics based educational videos on all aspects of weather, and physics. Lectures as well. To the point now where I have a solid intuitive understanding of the processes, but couldn’t tell you anything about the equations involved.
2:17 “the light does not have enough energy to knock the electrons lose” So what he is saying is that every time light hits metal the electrons in the metal change. I do not think this is true. And i still do not understand why infrared light goes through germanium.
You don't actually need gold to experiment light across metal. Many candy wrappers are made with glittered PET, it is s thin layer of aluminium on PET. It has the same effect and changes the colours of light.
Free electrons was first discovered by JJ Thompson, in a cathode Ray tube filled with vacuum. Electrons was deemed to be the carrier of electric charge (across vacuum). Electric charge induced on a glass sphere stay at the contact point, not so on a metal sphere. On metal sphere the charge spread evenly across a uniform sphere. So charge spread across a conductor naturally without the need of a carrier I.e. “electrons”. Electrons is however required to move charge across space, the vacuum and not conductor. Charge distribute through electrolyte requires electrons.
Another cool thing about germanium is its temperature dependent leakage in transistors and it’s use in the original fuzz (distortion) guitar pedals that Hendrix made famous.
Nothing gold is save to eat it doesn’t matter if you eat 100 gold leaf nothing will happen and gold also can’t get absorb by your body unlike lead so it’s save, the only down side is the poop will be glittery
Loved the explanation for how reflection works, you and 3blue1brown are the only ones I have seen that have explained it in that way, even though its one of the most accurate ways. If you want to see more stuff on light I highly recommend 3blue1browns optics series, its really good. Just realized this looks like a bot comment, I swear its not I just really like 3blue1brown.
Everybody who likes proper explanations even if they hurt their brain a bit and appreciates good educational presentation animations loves 3blue1brown. 😁
@@hunterwyeth a pop tart wrapper is vapor thin, I think I have seen light through that before. Real aluminum foil? No way, even the thinnest cheapest stuff won't have light getting through. That's someone confusing food wrappers for actual aluminum foil.
Get some scrap silicon wafers . Most are IR-transparent, depending on the doping. But silicon, like germanium, is a non-metal (no mallebility, no electron-sea, and insulating when cold.)
My mind is now absolutely blown by how IR transparent germanium is. I now want to see if it's possible to use a germanium prism in conjunction with solar cells. Heat/IR is the bane of solar cells so if that is filtered out then maybe a concentrator could allow more of the good stuff onto a given area without cooking the cells.
Very cool. I would like to have seen a demonstration that gold is not transparent to IR. This is why space probes near the sun are covered with gold foil.
This is exactly why we use germanium to make filters for JWST! Especially the mid infrared instrument MIRI, which measures wave links from 5 µm to about 28 µm
A compact disc has a thin coating of aluminum (and top coating of plastic). You can easily see a bright light source through it (If it's shiny on the top side and doesn't have a print covering it). So you do not need leaf gold to demonstrate this.
What people dont realize is, that for many lights colors even pass through our thickest stone walls. visible light is about 10THz-800THz and the color is the frequency. if you could see lower than red you would see electromagnetic waves pass walls below 1GHz (Wlan) and lower (Radio) its the same thing as light, but another frequency.
I want to first echo all the "Oooo, cool!" comments. But not using a tip when handling the gold leaf made me a bit crazy. A tip is a fine hair brush roughly the width of a piece of gold leaf. Lightly brushed over your skin it picks up oils, and then, touched to the edge of the leaf, can pick the leaf up. Even a wide sable paint brush would have done a better job than your fingers--particularly when the gold sticks to your fingerprints. Though the tooth thing was amusing😊
Are you Dr. Nicholas of Plexicorp by any chance? Did you have a discussion with Professor Scott of Edinburgh recently, about building a 1" thick whale tank?
Wow! Really cool and thanks for sharing. Question 🙋♀️ regarding a particular repeating experience: what allows light to pass through a human body, so that it becomes transparent and similar looking to a hologram, while walking barefoot in shallow moving water moving across a rock bed, at the base and near a short waterfall, of which doesn’t create a visible mist, in what I call living waters flowing, when taking pictures, with not only cell phones, but also a Nikon 42x optical zoom camera? Also on one occasion of this transparency blurry cloudy type effect, that was occurring in pictures of me, but not concerning others doing the same thing, so it appeared as unique to me, which was the last time experiencing this anomaly at that location (I have not been back because they put up fencing to keep people from entering the water ruining the experience and beauty of being there 😢), while walking back towards the bank to come out of the water; I bent down to pick up some stones I had left in the water to charge them and upon standing up: I got hit with an electric shock that moved from my feet and up through my body and out my head, of which I felt doing so. My body went completely tense at the moment, which was caught in pictures, and I looked solid in form, also the hair stood up on my arms for hours afterwards. Once I came out of the water, a weee bit shocked in a what the heck just happened sense; as my Dad helped me out of the water, as I was explaining what happened, he tried taking pictures of me to document the effect on my body and the camera being used to photograph me wouldn’t function to take any more pictures, at that moment. My Dad was taking the pictures and I’m not sure who had a more shocked 😳 expression, as he wasn’t sure what he just witnessed either. Back at this time is was not unusual for me to be blurry transparent looking in different photos of me at times, I seemed to effect the cameras functionality somehow. Side-note: I am a O Rh Negative blood type. If anyone can maybe explain the science behind my unique water baptism I’d appreciate it. Thank you. God’s Blessings 🙏🏼🕊️ PS The eating the golden apple reminded me of this statement: “Our persecutors imagine they see golden fruit in the dis-tance, but when plucked and tasted, they will find it to be Dead Sea fruit-apples of Sodom.” Knights Templar Ohio 1884
Very interesting and well prepared topic. What kind of filter would you produce if you vaporised glass with germanium? Could you sputter with germanium? Greetings from Bavaria
No germanium is a metal and hence conductive to electricity. If you try and establish an electric field it would 'short out' this field causing a current to flow. If yo establish a field near a conductive metal then this field can not penitrate themetal - this effect is commonly known as the Faraday cage effect.
@@michaelharrison1093 Germanium is a semimetal/metalloid and is not a great conductor of electricity. In a matter of fact copper conduct electricity more than 100 million times better than pure germanium.
Ok here is the guy who suggested the orange peel vs balloon. Got one for you that I have only seen with my own eye. For giggles after weighting something I seen a locking cap on the table so I spun it while spinning it was 4 grams and when it stopped it was 3 grams. I’m assuming because of centrifugal force since it’s exerting force outward it is also creating force on an angle to at point of contact. This making itself heavier. Just would love to see your take and wonder if this works with larger objects say weight plates. If so is there a formula for this. Btw the transparent gold was awesome.
So if you make a mirror with germanium instead of the regular metal layer, you obtain a perfectly normal-looking mirror but you can spy through it with a thermal camera 🤔
@7:59 "This is because shorter wave lengths of light, like blue and violet gets absorbed more" - this is clearly wrong as with this explanation the light getting through the gold foil should be favoring reddish light. Further I think the video should have mention that germanium is usually considered a metalloid or semimetal, not a metal. E.g. germanium was the material of choice as a semiconductor for the first transistors. Also all metals conduct electricity well, but pure germanium does not, however introducing specific impurities into germanium can make it conduct electricity mush better. Apart from these two issues I find the video is great and I enjoyed watching it.
Well, that pretty much has already been done as that's exactly what the lenses of thermal imaging cameras such as the one used in this video are made out of! :)
And most aliens are depicted with big black eyes without internal structures like eyballs or pupils - they might appear black because they only let infrared through. :-)
Cool fact: Axis thermal cameras have their lenses made out of Germanium (I assume most if not all thermal cameras do as well, but I know Axis does). Glass blocks IR so you can't have a glass lens on thermal cameras.
The lens on my welding helmet was gold. It reflected and absorbed enough of the light to prevent eye damage, but allowed just enough light through to see my work without striking an arc. It was especially good for looking at the sun during an eclipse.
My gold welding lens has been to three solar eclipses!
I read that first as "wedding helmet" and the thoughts I had were glorious.
Yeah, it's interesting that gold blocks all but green light, but when put on green welding glass you see a more colour accurate weld pool.
Just how expensive is that helmet?
@@EarthPlusPlastic Google will tell you faster than OP.
How can Action Lab be so consistently fascinating for so long? I love this guy. It's amazing that I get astonished every time I watch a video here, and this, once again, blew my mind so hard. Thank you so much for sharing these superb insights from nature itself. Please continue for good, humanity needs heroes like this.
I know many people are scared of physics classes because of the math. However, if we could get people just take a year of high school physics, you'd be surprised how the world opens up to you. It's not just about learning "how things work," it's also about learning to ask questions and then looking for the answers. I can look at anything in my office right now and find an interesting physics question about it that applies to the real world. I like science fiction, but the real world has so many crazy dynamics to it. Some of the demonstrations he does are classic physics examples, but he does a great job explaining it. And he comes up with demonstrations I've never seen before.
Next weeks video will be about 💩 gold bricks 🧱 . LoL 😂
It's cause he has an actual degree and legitimately understands how these things work.
yep, that's my boy
@@mhughes1160 you beat me to it "how to turn sh*t into gold - literally"
I never seen anyone shine light through gold leaf before! Quite an extra treat to see for sure in addition to the weird properties of germanium in the long-wave infrared!
literally the first time I had gold leaf in jr high science we discovered this.. like 30 years ago.
@@thaphreak Unfortunately, none of the science classes I had in school demonstrated that phenomenon, thus I was completely unaware of it.
You mean SOLID gold
@@thaphreak not everyone is curious enough to stumble onto things like this. It's a shame and one of the consequences of a standardized education where exploration isn't encouraged over regurgitation of just the info you're given and nothing more.
@@brfisher1123 it may not have been a demonstration. Sometimes kids just hold something up to see how it acts with the light. None of my science classes ever involved gold leaf, but I found this property elsewhere in metallic films, like the ones signs are made from and some parts of toys with metalized clear plastic.
One of the neat things about gold is that it's particularly good at reflecting IR radiation, so for EVA suits and the helmets used in the moon landings, their visors are coated with a very thin layer of gold to more effectively protect them from the unabated IR radiation of direct sunlight without an atmosphere.
So the reflectivity of very thin gold also depends on frequency, and not just brightness?
@@GeoffryGifari I mean, the reflectivity of all metals differs on the frequencies involved. Gold just on its own is good at reflecting infrared light, which is why the James Webb Space Telecope uses a gold coating for its focusing mirrors since other materials would absorb a higher portion of the deep infrared-shifted light they designed it to observe.
Many metallic films are mildly transparent. That includes mirrors, which are usually painted on the back for both durability and opaqueness. I used to make signs, and most of our gold or silver-colored adhesive films would let enough light through that you could read a newspaper through them, or use as a rudimentary one-way mirror when the other side was well-lit. (Not requiring a flashlight that rivals the sun...) That includes the "metal-flake" style films, as well as the flat/mirror. I believe most of them were also considerably cheaper than gold leaf.
Gold is the classic because it is so damn malleable (in the technical sense of the word meaning it can be hammered very flat)
Hi, I really like your channel. However, this time there is a mistake. Germanium is not a metal. It is a semiconductor meaning that its electrons are bound and cannot move freely. Only when the light photon energy exceeds the binding energy (also called the band gap), the electrons become free. The band gap of germanium is in the near-infrared range. Therefore, the visible light gets absorbed/reflected and the thermal mid-infrared light passes through.
Although germanium looks like a metal, its mechanical properties are similar to insulators - it is brittle and cannot be forged like metals.
The glass in turn is mirror-like in infrared since its ions oscillate in the light field and act similar to free electrons in metals. Germanium and silicon are non-polar - they don't have positive and negative ions. So they are transparent in the whole infrared range. This is a great advantage and the most of infrared optics is made out of germanium or silicon.
whoa
All elements are classified as a metal except Hydrogen and Helium.
@@Vincent67337that is only an astronomy thing. Chemists and physicists do not call germanium metal...
I thought being a semiconductor played a part...
@alexejpashkin3562 Once he showed the IR light shining through, I knew he had a semiconductor. However, I don't think *"The glass in turn is mirror-like in infrared since its ions oscillate in the light field and act similar to free electrons in metals."* is a correct explanation. One, glass doesn't act like a mirror in the infrared anymore than visible light does. Glass actually absorbs infrared light. And I could be wrong, but I always assumed this absorption was mediated via phonon modes, not ion oscillations. But now I need to look it up and get back on that.
(0:50) *Now, just so you don't think this is normal, to be able to see through something with infrared light* I'm glad you pointed that out. Movies and TV dramas tend to have unrealistic portrayals of using infrared cameras to see through walls or ceilings.
6:43 he's gonna get regeneration from that
I'm trying to do the math on how much gold is in a golden apple vs how much he consumed. a golden apple has 17 metric tonnes and one gold leaf is about 18 mg. let's assume he consumed 1/8th of an apple. if he consumed one eighth of a golden apple in minecraft he'd get about 0.63 seconds of regen and 15 seconds of absorption if the effects translated to real life 18 milligrams of gold would give.... idk a couple nanoseconds probably. I tried to do the math but failed.
This is why germanium is used for the lenses of thermal optics. Thermal optics operate in the far IR spectrum and glass blocks it, so germanium has to be used. It's one of the reasons thermal optics are expensive. Glass will, however allow near IR through, so it's suitable as lenses on night vision optics that operate in that spectrum (i.e. digital IR night vision). Thermal is passive and does not require an active light source (far IR is "heat"). Near IR devices require active emitters (IR lights) to "see" in total darkness.
I've always wondered what IR windows were made of and now you've clarified my doubts. Thanks for the video!
I like to see your thought process. You first made a video about laser metal cutting, and then you wondered if red hot metals can reflect light or not, and now you are working on light penetration in metals. You are personally educating yourself and also make all of these processes available for us, viewers. Keep up with good work.
And for the next video, i would like to see if electrical current or static charges would effect the reflection properties or not (because you mentioned that those properties are strongly related to free electrons and their specs).
Plasmachannel made a nice video on electrostatic materials.
" i would like to see if electrical current or static charges would effect the reflection properties or not"
well it does though not on metal but LCD
You know those transparent umbrellas you sometimes see in Japan? They are freakily good camouflage against thermal cameras/ sights.
and that's why astronauts have gold visors =)
CDs without any printing can also let light pass through. The metallized layer inside is quite thin.
@@jeanrenaudsagswing I always thought that was because the tiny holes which carry the information. But the metal could also be see through I learned today ;-)
I thought it was because they were trying to look like pimps. Damn it dad! Yet another lie!
@@DonariaRegia lol
THANK YOU FOR DOING GOLD! This is something I've been wondering about for years!!!
the gold "filter" looking greenish makes it look perfect as an in-camera nightvision effect! I imagine this would be a cool filter to use in photography or hobby filmmaking
Gamma rays: am I a joke to you
Gamma is just X-rays, just light with a higher energy...
@@DonariaRegia You are thinking of Neutrinos Cosmic Rays are atomic nuclei that move at a high %C and are mostly stopped by the upper atmosphere. They are working on using this decay to take deep scans of things using the produced Muons.
Wouldn't higher frequency light be more inclined to be absorbed, because they have energy for the electrons to be excited? Or is there some new effect at high frequencies?
@@DonariaRegia 😹
It's often referencing the emission source of the high energy photon: from a nuclear transition (gamma) or an atomic one. There are actually some nuclear energy transitions in Thorium that result in a 149.7nm gamma ray photon out. Relatively low energy.
6:53 NileRed made himself gold grillz to “avoid crippling embarrassment” (and posted a video) 😂
Germanium also has an extremely high refractive index. Its used for lenses in thermal imagers and for focusing CO2 lasers. ❤
Thanks again for a most informative and educational video! It's interesting how materials can be be invisible to certain wavelengths of electromagnetic energy.
Your video from about two years ago on making transparent metals was interesting too.
And for those who didn't know, astronaut helmets have a gold layer as well which is used to block the sun's intense unfiltered light while in space.
Love your videos, I wish I had had a science teacher like you when I was in school.
Now we have to worry about spy cams with metal lenses. Gee thanks 😂
A spy cam seeing in infrared? Army-related then
@Julzaa I'm more thinking about the gold leaf
@@Autistic_Artist there are already see-through mirrors, the gold leaf as a lens is just a gimmick
all of a sudden mk-ultra is muy kool Ultra real and true
You think ultra sonic cameras need lenses? They already have them.
In the entire Elements table, is there this one and only one metal that does this? Is it maybe the very only (in solid state) element that does this? Blocking visible light, but letting through infrared. What an odd characteristic. First time I ever hear about this. As always, great video! And thanks much for sharing these fascinating oddities!
I love how the letters printed on the Ge sample weren’t see thru but the rest of the sample was!!! 😮
So, can we use germanium glasses to correct a snake's prescription if they suffer from visual distortions?
When I was little I remember playing with aluminium foil and I liked how u could see trought it if u placed near your eyes
The infrared camera shots of germanium are absolutely insane. I just cannot reconcile that with my previous knowledge of physics.
That was a pretty cool video. You should make a follow up short about the James Webb telescope, and why they use gold and beryllium on the mirrors.🧐🙂
Some infrared-vision aliens gotta have extremely strong fish tanks
I know many people are scared of physics classes because of the math. However, if we could get people just take a year of high school physics, you'd be surprised how the world opens up to you. It's not just about learning "how things work," it's also about learning to ask questions and then looking for the answers. I can look at anything in my office right now and find an interesting physics question about it that applies to the real world. I like science fiction, but the real world has so many crazy dynamics to it. Some of the demonstrations he does are classic physics examples, but he does a great job explaining it. And he comes up with demonstrations I've never seen before.
The problem is the formal education side requires the math… I was interested in meteorology as a kid, but struggled with advanced math equations so I gave up on that dream.
As an adult, I’ve watched many physics based educational videos on all aspects of weather, and physics. Lectures as well. To the point now where I have a solid intuitive understanding of the processes, but couldn’t tell you anything about the equations involved.
I really needed this! Just thinking about how I would get a signal into a faraday cage. Looks like laser + thin metal is the way to go.
2:17 “the light does not have enough energy to knock the electrons lose” So what he is saying is that every time light hits metal the electrons in the metal change. I do not think this is true. And i still do not understand why infrared light goes through germanium.
Love this channel. Nothing but learning disguised as fun.
Did you recover the gold in your toilet 😂 ?
For $1 of gold?
Fun fact: Thermal camera lenses are made of solid germanium to block all the "normal" light and only let infrared light go to the sensor
You don't actually need gold to experiment light across metal. Many candy wrappers are made with glittered PET, it is s thin layer of aluminium on PET. It has the same effect and changes the colours of light.
Free electrons was first discovered by JJ Thompson, in a cathode Ray tube filled with vacuum. Electrons was deemed to be the carrier of electric charge (across vacuum).
Electric charge induced on a glass sphere stay at the contact point, not so on a metal sphere. On metal sphere the charge spread evenly across a uniform sphere. So charge spread across a conductor naturally without the need of a carrier I.e. “electrons”. Electrons is however required to move charge across space, the vacuum and not conductor.
Charge distribute through electrolyte requires electrons.
That's why I subscribed him early, he never let my interest down.👍👍👍
Love the color cast when you put the gold up to the camera.
Another cool thing about germanium is its temperature dependent leakage in transistors and it’s use in the original fuzz (distortion) guitar pedals that Hendrix made famous.
6:26 how much gold could someone eat before it wasn't safe? What would happen if they just kept eating more and more?
Nothing gold is save to eat it doesn’t matter if you eat 100 gold leaf nothing will happen and gold also can’t get absorb by your body unlike lead so it’s save, the only down side is the poop will be glittery
'Look at this light shining through metal'
Next shot: shows a disc of the semi conductor metalloid Germaniun 😅
Like your videos a lot James.
6:53 I never thought I would ever hear you say that.
He probably thought the same😁
The utter flex in this line
To do physics experiments like this everyday would be a dream job for some, like me.
So cool! Very constant color going through the gold!
I loved Germainium for making fun guitar pedals already. Even better now 🔥❤👀
Loved the explanation for how reflection works, you and 3blue1brown are the only ones I have seen that have explained it in that way, even though its one of the most accurate ways. If you want to see more stuff on light I highly recommend 3blue1browns optics series, its really good.
Just realized this looks like a bot comment, I swear its not I just really like 3blue1brown.
Everybody who likes proper explanations even if they hurt their brain a bit and appreciates good educational presentation animations loves 3blue1brown. 😁
00:04 "today im going to show you how to shine a light through solid metal" processeds to drop a nuke
real
Lmaoo guess it worked
It worked a bit TOO well
My brain cant compute this knowledge lol
Love your videos, thanks for showing us cool stuff! :)
yeah i agree
Also the lens in that thermal camera you use is made of germanium. Glass (which is used in visible-light cameras) blocks infrared.
Nice video, Transparent Aluminum has similar properties, that too can be covered in future videos.
If you had a bar of gold, could you have a bright enough light to eventually shine through it?
Thanks, great explanations!
Would light pass through an iron sheet with the same thickness?
You should try to make lenses for a telescope or magnifying glass with Germanium.
You can also see through aluminum foil with a bright light
Depends on the quality.
I’ve read about cases where people have made whiteout glasses out of thin foil wrappers like you’d find around a pop tart
@@hunterwyeth a pop tart wrapper is vapor thin, I think I have seen light through that before.
Real aluminum foil? No way, even the thinnest cheapest stuff won't have light getting through.
That's someone confusing food wrappers for actual aluminum foil.
7:47 But this is normal. Most Metal are as thin translucent
I think that's the point. They're explaining why this is the case then demonstrating it.
How did I not know this?
Ikrr
did you know you can also do this with mylar
Education system in shambles
coz you can't see infrared
Get some scrap silicon wafers
. Most are IR-transparent, depending on the doping. But silicon, like germanium, is a non-metal (no mallebility, no electron-sea, and insulating when cold.)
It's crazy how important of a role Light plays within our Universe.. 💡 As well as the interconnected Magnetic Fields.. 🧲 and Electricity 🔌 ⚡ 🔋
Aren't "one side" mirrors using the same effect, but with silver coating of the glass?
Thanks!
Thanks-Awesome!
My mind is now absolutely blown by how IR transparent germanium is. I now want to see if it's possible to use a germanium prism in conjunction with solar cells. Heat/IR is the bane of solar cells so if that is filtered out then maybe a concentrator could allow more of the good stuff onto a given area without cooking the cells.
excellent..fascinating demonstration and clear explanation
Very cool. I would like to have seen a demonstration that gold is not transparent to IR. This is why space probes near the sun are covered with gold foil.
Excellent, never ceases to amaze
Your videos are always so cool!
This is exactly why we use germanium to make filters for JWST! Especially the mid infrared instrument MIRI, which measures wave links from 5 µm to about 28 µm
Could germanium be formed into a lens to focus infrared light?
A compact disc has a thin coating of aluminum (and top coating of plastic). You can easily see a bright light source through it (If it's shiny on the top side and doesn't have a print covering it). So you do not need leaf gold to demonstrate this.
What people dont realize is, that for many lights colors even pass through our thickest stone walls. visible light is about 10THz-800THz and the color is the frequency. if you could see lower than red you would see electromagnetic waves pass walls below 1GHz (Wlan) and lower (Radio) its the same thing as light, but another frequency.
I want to first echo all the "Oooo, cool!" comments. But not using a tip when handling the gold leaf made me a bit crazy. A tip is a fine hair brush roughly the width of a piece of gold leaf. Lightly brushed over your skin it picks up oils, and then, touched to the edge of the leaf, can pick the leaf up. Even a wide sable paint brush would have done a better job than your fingers--particularly when the gold sticks to your fingerprints. Though the tooth thing was amusing😊
Are you Dr. Nicholas of Plexicorp by any chance? Did you have a discussion with Professor Scott of Edinburgh recently, about building a 1" thick whale tank?
I laughed so hard about the gold grills bit. Clever! But I wonder how gold affects mouth bacteria; is it beneficial? Asking for a friend.
Gotta love things that exhibit characteristics of both a wave and a ray.
Pretty similar to space suit helmets. Except it’s applied differently. That or Mylar.
All your videos are amazing, keep it up! 😁
anything is transparent if you make it thin enough
your content is so unique and fascinating. thank you!
Wow! Really cool and thanks for sharing. Question 🙋♀️ regarding a particular repeating experience: what allows light to pass through a human body, so that it becomes transparent and similar looking to a hologram, while walking barefoot in shallow moving water moving across a rock bed, at the base and near a short waterfall, of which doesn’t create a visible mist, in what I call living waters flowing, when taking pictures, with not only cell phones, but also a Nikon 42x optical zoom camera? Also on one occasion of this transparency blurry cloudy type effect, that was occurring in pictures of me, but not concerning others doing the same thing, so it appeared as unique to me, which was the last time experiencing this anomaly at that location (I have not been back because they put up fencing to keep people from entering the water ruining the experience and beauty of being there 😢), while walking back towards the bank to come out of the water; I bent down to pick up some stones I had left in the water to charge them and upon standing up: I got hit with an electric shock that moved from my feet and up through my body and out my head, of which I felt doing so. My body went completely tense at the moment, which was caught in pictures, and I looked solid in form, also the hair stood up on my arms for hours afterwards. Once I came out of the water, a weee bit shocked in a what the heck just happened sense; as my Dad helped me out of the water, as I was explaining what happened, he tried taking pictures of me to document the effect on my body and the camera being used to photograph me wouldn’t function to take any more pictures, at that moment. My Dad was taking the pictures and I’m not sure who had a more shocked 😳 expression, as he wasn’t sure what he just witnessed either. Back at this time is was not unusual for me to be blurry transparent looking in different photos of me at times, I seemed to effect the cameras functionality somehow. Side-note: I am a O Rh Negative blood type. If anyone can maybe explain the science behind my unique water baptism I’d appreciate it. Thank you. God’s Blessings 🙏🏼🕊️ PS The eating the golden apple reminded me of this statement: “Our persecutors imagine they see golden fruit in the dis-tance, but when plucked and tasted, they will find it to be Dead Sea fruit-apples of Sodom.” Knights Templar Ohio 1884
Very interesting and well prepared topic. What kind of filter would you produce if you vaporised glass with germanium? Could you sputter with germanium? Greetings from Bavaria
So... Its possible to make a infrared telescope with germanium lens?
So if the gold shines through the gold leaf, then light penetrates into the metal, not just the surface
Interesting and you can even buy germanium lenses.
Why didnt he got regeneration after eating the golden apple?
Edit:Mom, i am famous
Or absorption...
Gold apple just grants full health
Didn't he get**
😂😂😂
or get "kicked out"
Transparent Aluminium?
I waited for it, too.
7:23 Mostly green light is coming through the gold. I wonder if this is related to the red colour when gold is mixed in glass.
Presumably the opacity of the Germanium window can be varied with an electric field?
On spot
No germanium is a metal and hence conductive to electricity. If you try and establish an electric field it would 'short out' this field causing a current to flow. If yo establish a field near a conductive metal then this field can not penitrate themetal - this effect is commonly known as the Faraday cage effect.
@@michaelharrison1093 Germanium is a semimetal/metalloid and is not a great conductor of electricity. In a matter of fact copper conduct electricity more than 100 million times better than pure germanium.
Ok here is the guy who suggested the orange peel vs balloon. Got one for you that I have only seen with my own eye. For giggles after weighting something I seen a locking cap on the table so I spun it while spinning it was 4 grams and when it stopped it was 3 grams. I’m assuming because of centrifugal force since it’s exerting force outward it is also creating force on an angle to at point of contact. This making itself heavier. Just would love to see your take and wonder if this works with larger objects say weight plates. If so is there a formula for this. Btw the transparent gold was awesome.
Silicium is also very intersting because it is both used to make visible detectors and IR lenses
So if you make a mirror with germanium instead of the regular metal layer, you obtain a perfectly normal-looking mirror but you can spy through it with a thermal camera 🤔
That's why it's possible to make partially silvered mirrors like the ones in gas tube lasers or in interrogation rooms.
@7:59 "This is because shorter wave lengths of light, like blue and violet gets absorbed more" - this is clearly wrong as with this explanation the light getting through the gold foil should be favoring reddish light. Further I think the video should have mention that germanium is usually considered a metalloid or semimetal, not a metal. E.g. germanium was the material of choice as a semiconductor for the first transistors. Also all metals conduct electricity well, but pure germanium does not, however introducing specific impurities into germanium can make it conduct electricity mush better. Apart from these two issues I find the video is great and I enjoyed watching it.
So can we shape Germanium discs into a lens shape and make an IR focusing lens?
Can you make an infrared lens out of germanium then?
Well, that pretty much has already been done as that's exactly what the lenses of thermal imaging cameras such as the one used in this video are made out of! :)
The Action Lab: "Woah, I am literally seeing through solid gold!!!!"
Airline pilot: (Yawns) "Tuesday"
But can you build a focusing lens out of it?
I can shine visible light through the element two above germanium. It just has to be formed under extreme heat and pressure.
Perhaps this is why UAPs never seem to have windows; their eyes might see infrared, so the windows are out of Germanium and appear opaque to us. :-)
And most aliens are depicted with big black eyes without internal structures like eyballs or pupils - they might appear black because they only let infrared through. :-)
@@NuntiusLegis Or it is just fashion on their planet...
So fascinating! Thanks for sharing this!
An interesting point is that gold (chloride) is used to make red colored glass.
Cool fact: Axis thermal cameras have their lenses made out of Germanium (I assume most if not all thermal cameras do as well, but I know Axis does). Glass blocks IR so you can't have a glass lens on thermal cameras.