SciShow Tangents - SciShow Tangents Enhanced Classics - Light

Episode Date: December 29, 2020

SciShow Tangents is taking a short break, but we didn't want to totally leave you hanging! You're about to listen to a rerun of the Light episode, but with a special twist: we recorded a new Ask the Science Couch and Butt Fact! Next week we'll be posting another of these Enhanced Classics, then we'll start releasing regular, full-length episodes again. Thanks for hanging with us!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Stefan: @itsmestefanchin Ceri: @ceriley Sam: @slamschultz Hank: @hankgreenIf you want to learn more about any of our main topics, check out these links:[Truth or Fail]EROShttps://www.ncbi.nlm.nih.gov/pubmed/25788334MOZEhttps://www.nature.com/articles/s41593-019-0389-0FReSHhttp://www.nature.com/nature/journal/vaop/ncurrent/full/nature10428.html[Fact Off]Eidophorhttps://www.earlytelevision.org/eidophor.htmlhttps://hackaday.com/2016/03/15/retrotechtacular-eidophor-an-unknown-widely-used-projector/http://www.film-tech.com/ubb/f1/t004319.htmlhttp://www.earlytelevision.org/yanczer_eidophor.htmlCentennial lighthttp://www.centennialbulb.org/index.htmhttps://www.mentalfloss.com/article/66009/light-bulb-has-been-burning-1901https://www.lampsplus.com/ideas-and-advice/how-an-incandescent-light-bulb-works/https://spectrum.ieee.org/tech-history/dawn-of-electronics/the-great-lightbulb-conspiracyhttps://www.npr.org/2019/03/27/707188193/the-phoebus-cartel[Ask the Science Couch]Incandescence: http://edisontechcenter.org/incandescent.htmlhttps://physlab.org/wp-content/uploads/2016/03/Planck_ref8.pdfhttps://www.fi.edu/history-resources/edisons-lightbulbLEDs:https://www.circuitbasics.com/what-is-a-diode/http://needtoknow.nas.edu/www7.nationalacademies.org/led-lighting/index-2.htmlhttps://www.lrc.rpi.edu/programs/nlpip/lightinganswers/led/color.asphttps://www.mrsec.psu.edu/content/light-emitting-diodes[Butt One More Thing]Fluorescent E.coli for colitishttps://www.embopress.org/doi/full/10.15252/msb.20167416

Hello there, listeners! We're taking a little break here at SciShow Tangents until the new year. So, what you're about to hear is an episode from our back catalog, but we're going to mix it up a little bit. See, every week we get a bunch of great listener questions, but we only answer one of those questions because we only have time for one. So in this episode, we've recorded a whole new Ask the Science Couch with a whole new listener question, and on top of that, there's a new but one more thing but fact. So you can be sure to listen all the way to the end if you want to hear that. Because of course you do. Hello and welcome to SciShow Tangents, the lightly competitive knowledge showcase starring some of the geniuses that make the YouTube series SciShow happen.

This week, as always, I'm joined by Stephan Chayden. Hello. Stephan, what's your favorite kind of hot dog? Ooh, just a normal one. You just, like, actually, well, okay. Costco. The Costco hot dog. Yes! The Costco hot dog. And! The Costco hot dogs.

And you put a little onion on there and some extra. And you bring your own cayenne pepper and just dust, do a light dusting. Yeah, we just lost a bunch of listeners. What's your tagline? What's the point of firm tofu? Sam Schultz is here too. What's up? Sam.

Yep. What's your tagline? I need a blankie. That's my tagline. You got one right behind you. Oh, shit. I do. Sari Riley's here as well.

Yep. What's your tagline? Hot dog gremlin. He eats all the hot dogs? Yeah, I guess. Or he's made of hot dogs. Or that's who you send to fetch your hot dogs. I think he's the off-brand hamburglar.

And I'm in green. My tagline is pink tomatoes. Every week we get together here on SciShow Tangents to try to one-up a maze and delight each other with science facts.

We're playing for glory, but we're also keeping score and awarding Sam bucks from week to week. We do everything we can to stay on topic, but we probably won't be great at it.

So if the rest of the team deems your tangent unworthy, we will force you to give up one of your sandbox. So tangent with care. And now, as always, we introduce this week's topic with the traditional science poem this week from Stefan. Photons hurling through space at speed, giving me life, warmth, and vitamin D. Everything that we know just couldn't be without the sparkle that the sun continuously sets free oh yeah light is the only way that darkness can be cured even if the physics can be quite absurd is it oscillating particles or waves i'm not sure i mean two slits tells us it's both at least that's what i heard but the vastness of space is no challenge to transcend at a uniform speed that's

hard to comprehend but then to a prism it concedes and must bend. A rainbow just reminds us that light is our friend. A lamp for my plants. A bright white to mesmerize. And I couldn't see France without light hitting my eyes. Helping us study microbes and those little points in the sky. Touching everything always. Light was quite a pleasant surprise.

Oh, yes. I was very surprised the first time i saw you come out i guess you open your eyes for the first time whoa it's bright what a surprise but it's a good one yeah yeah that was a good poem thank you that's all i got on that one yeah it was long you worked on it yeah we don't have any time to talk about it oh shoot You worked on it. Yeah, we don't have any time to talk about it. Oh, shoot.

Sari, what is light? I don't know. Visible light is generally defined as having wavelengths from 400 to 700 nanometers. And then there's infrared, which is longer than that. And ultraviolet, which is shorter than that, which is just outside the realm of human vision. So is it defined by what we can see or what any animal could see? It's defined by what we could see, by what humans could see. So other animals can see. So when we see outside of that range.

When we say light, we mean visible light. Yeah. Generally. Generally, yeah. The thing that we can perceive. Okay. So it is definitely, it doesn't come down to a scientific thing so much as it comes down to like human perception, which is, you know, certainly affected by science. But that range is just what we can see.

And it turns out like there's reasons why we can see that range. And largely it's because that's the sort of most of the wavelengths that are around on Earth. The rest of them get either not emitted by the sun at all or they get absorbed by one thing or another on their way to us. So that's the sort of like the window where the best range of stuff. But there's other reasons why too. And I don't know what they are. There's like biochemical reasons why these are better wavelengths to see than some other broader ones. I would just imagine that those are the ones that help you navigate the space that you're in they're more

plentiful and and there's a lot of variety so there are things within that range that absorb or emit in that range and so you get this variety that we can see and that's like better differentiate the visible plane but bees are like i don't need to see all that i just need to see flowers really good so light seems pretty simple then what the visible spectrum is is not super complicated in terms of just like this is just the window once you start getting into like the mathy stuff what is a photon why why like different frequencies different, different intensities of light. Polarization of light, refraction of light. I'm just going to say more science-y words that I don't really know how to define because that is where light gets confusing.

And we also need light for biology things. So like photosynthesis is a light-dependent reaction. Sure, of course. Putting sun on your butt. Correct. That helps with things, right? where of course sun on your butt correct yeah helps with things right what what any sun on your butt no people sun in their butt why on instagram does it helps align some stuff no it doesn't help align some stuff they say that it's like it gives you like a full day's dose of vitamin d just to put your butt up to the sun for for five minutes i feel like that has an assumption that your butt is like more absorbent of light than the rest of your body

and that we're doing a crime by hiding it in pants we are doing it a crime yeah that's the yeah that's the natural powerhouse of the body this is so transparent to me that that person was like oh i'm gonna get a bunch of people paying attention to me if I shine my butthole. Is it butt or butthole? It's butthole. Oh, well, that makes sense. Perineum. Perineum?

Anyway, why? Caribbean, Caribbean, Perineum, Perineum. Both is correct. Really? I think Perineum and Perineum are both correct, yes. Same with Caribbean. Pirates of the Perennium. I didn't want to say it, but you kept saying it over and over.

Light's etymology is kind of boring. Okay. Is it like bone? It just means the thing? Yeah, my guess is that light existed. We had to have something to describe why it was bright half the day and not so like light as a word. So it comes from the Latin lux. For light?

For light. Greek, leukos, for white. Okay. It is strange to me that we think of light as white. It's usually yellowish or transparent, sort of. Sun's white. Right? Yeah. white like it's usually yellowish or transparent sort of sun's white right yeah the sun's well the sun if you're outside of our atmosphere the sun is totally white from our view it's a little bit yellow because of because some wavelengths are getting scattered around the blue ones

that's why the sky is blue right makes the sun yellow i haven't taken a good look at the sun in a while don't don't do Okay. And now it's time for Truth or Fail, where one of our panelists has prepared three science facts for your education and enjoyment, but only one of those facts is real. The other two are lies, and the other panelists have to decide which is the truth and the lie.

And if you get it right, you get a Sambuck. I am the purveyor of today's lies. My name is Hank, and I want to tell you about optogenetics. Basically, genetically modifying cells to do specific things when exposed to light or different wavelengths of light, even. And it's a super powerful tool that's opened up a lot of doors in the last five years specifically, and it's a really exciting new thing. So which of the following is a real-life application for optogenetics that has been tested in laboratories? Fact number one, a system called EROS, which stands for erectile optogenetic stimulator, which uses light to stimulate erections in rats,

or a system called MOSE, which stands for Mouse Zone Exploration, which uses implanted fiber optic lights that scientists could use to affect a mouse's decision as it moved through a maze. Mice guided by the MOSE implants, controlled by scientists, solve the maze 30% faster than those who are not guided. Or fact number three, a system called FRESH, which stands for Fly Red Stimulated Hunger,

that uses red light to drive fruit flies away from rotting fruit that they like to eat, and weirdly had the side effect of making males apparently disinterested in sex. I feel like if it involves a boner, it's real. It's true. People are very interested in boners. People want that boner technology. Yeah. I don't think you'd want boner technology to shine light on your head, would you?

Look, whatever it takes. I didn't say that it was in your head. Interesting hint. Light on the dick. Daylight bulbs right on the inside of your pants nestled up against the perineum. That's way easier

than filming yourself in the backyard. Oh, actually, we could totally sell that. Just like LEDs in your underpants. Blue daylights. Yeah. Great new vitamin D creation. What is a sunlight carrying with it that light from a light bulb is not carrying with it that gives you cancer and stuff? UV radiation.

Okay. That just comes from the sun. And that's what I should have known that probably. And now I do. We learn here. Yeah. We do. So not helpful for your ability to tell

which one is true that's because i have no idea which one is true all of these sound like acronyms that scientists would come up with because they like fun words i do feel like the fruit fly one that one feels the fakest to me which only narrows it down a little bit because i feel like over the course of like doing these podcasts and like Beyonce I've heard about mice getting light shined into their brains to do different things but I've never heard about flies but I think the flies are just getting exposed to

light and not just their brain genetically they modify the entire fly oh my god so that they shine red light on it and it changes like how their hormones are expressing that one is realistic to me just because it's so like relatively easy to modify a fruit fly gene. But if they're not in the light, do they still want that fruit? If they're not in the light, they want the fruit again.

Yeah. So you turn the red light on and they're like, I don't want to eat, but I'm very hungry. And suddenly I also don't want sex. This one's really hard. This one's really hard. Yeah. Good job. They're all believable, I guess.

Okay. Two of them are sex. One of them is not. One of them's towards sex and one is away from sex. This one's really hard. They're all believable, I guess. Okay, two of them are sex. One of them is not. One of them's towards sex, and one is away from sex. So I'll go with the boners. Stephen's gonna go for the boners. What do you think about the mice zone one?

I'm torn between that and the fruit flies. I don't think I can go with that one. I think I'm gonna go with the mouse zone. Mouse zone for Sam? Okay, I'm gonna do mouse zone two. I think I'm going to go with the mouse zone. Mouse zone for Sam. Okay, I'm going to do mouse zone too. I'm going to trust you about the fruit flies, Sam. Oh my God. Well, don't blame it on me.

Fruit flies is fake. Okay. Mouse zone is fake. It's boners, everybody. Oh no. It's boners, everybody. Boners never let me down. I should have gone with...

You should have gone with your first instinct. Yeah. Scientists used optogenetics to create a blue light responsive control over cyclic guanosine monophosphate in the corpora cavernosa, which is the erectile tissue. That's one of the main messengers involved in erections. And when they shined blue light on the rats, so not on their brains, but like through their skin. Turn on a mood light underwear it worked yeah so one of the reasons is like yes there's a lot of money in boners but the second is that this is a really clear signal like you know when it's working oh yeah because like you

can see it's like an on-off switch you can see when the boner is happening and not happening yeah a literal on-off switch yeah we're turned when the boner is happening and not happening. Yeah, a literal on-off switch. You're turned on now. Do they have to be seeing the light? No, I think it's through the skin. Whoa. And number two, the maze thing. There is a thing where basically scientists have been able to have one mouse go through a thing while wearing that thing on its head.

And then they can program that knowledge into another mouse i don't like that so that's what this was based on but that's not a thing they couldn't like tell it to go left or right which i feel like they should they could yeah they could they just haven't done that yeah and then the red stimulated hunger thing um that was made up but there is a cool thing where male fruit flies, their brain circuits are first activated by smelling fruit before they begin to detect female pheromones. So they kind of have to like smell rotting fruit before they can get it on, which is interesting. For a fruit fly, that makes sense. And optogenetics has been used to control Drosophila courtship and sleep cycles.

So there is optogenetic research on drosophila, but not this. Is it because they've got to lay their eggs somewhere where their babies are going to have rotten fruit to eat? Maybe, yeah. They do like, yeah, that's a good point. Interesting. They just like literally can't detect female hormones until they smell rotting fruit first. That's really cool and gross. This is not how it works for us.

So I guess that means I get two points. That one was too science-y. All right. Next up, we're going to take a short break, and then it'll be time for the Fact Off. Welcome back, everybody. Sam Buck totals. Sari and Sam are tied with zero, and Stefan and I are in the lead with two. Feels good, huh?

It's going to be hard to catch us. Oh, it's great. Impossible, even. We have infinite percent more points than you. Now get ready for the Fact Off, where two panelists have brought science facts to present to the rest of us in an attempt to blow our minds. And we each have a sandbuck to award to the fact we like the most. Who's going to go first? Well, whoever is closest wins.

Deep-sea creatures live below the photic zone or sunlit zone, but it's not totally dark down there thanks to bioluminescence. About what percentage of the main taxa of deep sea animals produce light? 80. We got 80. Oh, goodness. 75. Okay, 75.

75! Oh! I helped you go high! I was going to say like 0.3%. You know, ultimately, nobody got a point for that. And you don't get to go first, which isn't so bad. That's true. Oh, well, okay.

I thought you got to pick now. Oh, yeah, you can pick. Yeah, you want to pick? Oh, I get to pick. I'll go first. During the Apollo program, there were, if you think of the image of the Apollo program, it's a bunch of people sitting in a room. It's the 60s.

They're looking up at a big screen that has a live image of the astronauts fluttering around in space projected onto it. But how the heck did they get that big picture up there? Because CRT projectors, which are the old type of projectors with the red, green, and blue lenses, couldn't project that big. Like tube TVs couldn't get that big. They were film projectors,

but they weren't like printing this live footage onto film and playing it out really big. So how did they do it? The answer is the EDA-4, which is a high quality live image projector invented in the early 40s by Fritz Fischer, who is a Swedish physicist. And like basically everything invented before things went digital, it was super complicated, super weird and used physics in wild ways to solve problems

that we just make computers do now. So how it worked was a live video feed was fed into an electron gun, which translated the image into an electron beam. And then they would shoot the beam onto a mirror that had a one micron thick coating of oil. So the electrons would hit the oil and they would deform the oil. So like, let's say it's a black and white image, each little gradient between black and white would hit and deform it a little bit differently. So the more white it was, the more it would deform the oil. Then a light was shined onto the mirror and wherever the electrons hit the oil, the light would bend it just enough to get past this barrier inside of it

between the light and the lens. Every bit of light that hit a part of the oil that was deformed bounced just barely enough that it could get between the cracks in this barrier. There were like little cracks in the barrier and everything that just bounced straight off hit the barrier. So that became like the black in the image. And while this was all happening, the mirror was rotating because once the oil got hit by the electrons, it couldn't be hit again because it was already bent up.

So there was a squeegee that it would rotate under that would smooth the oil back out so that the electron beam could shoot it. How often? I think somebody said it rotated once every 24 hours. The squeegee? The mirror would do one full rotation. Oh. So it was like really big.

So really slow? Really big and really slow. Because I guess the electrons were making really tiny dents. Electrons are tiny. They're very small. We got into one thing. So all this was happening in a climate control vacuum chamber because the oil had to be just exactly the right temperature and the electrons had to be in a vacuum too. And to do color, you'd have to have

three of these all lined up perfectly shooting at the same time. Each one costs $2 million about, and they broke if anything went wrong with the oil. You had to take the whole thing apart and re-oil it and do all kinds of stuff to it. And they weighed literally one ton, but they could do huge live projections that were like 40 by 50 feet, and they were super bright, way brighter than anything else at the time. So they were used in sports stadiums, concert venues, and theaters everywhere from the 40s until the 90s when digital projectors were invented. And there are lots of people talking about them on forums and stuff, but as far as anybody knows, there aren't any of them left that are operational.

And they're redoing right now the control room for the Apollo program, but they're not redoing those. They're just using digital projections now. So it's like a totally dead technology. How hard is it to do something one micron thick like is should i be impressed that they were able to do that in the 40s well especially that they could squeak they had like squeegee it on at one micron thick once the little divot was made did it just stay there it stayed there until it got squeegeed off okay so. So, yes. Was the squeegee wiping off the oil, or is it like a sandbox where you smooth it over? Sandbox.

Okay. So, a human hair is about 75 microns across. Whoa. Very small. Yeah. You're not cooking on this disc. No. Not enough oil for that.

All right. Probably a mineral oil would be my guess. Not a... Yeah. I think it was, like, proprietary. I couldn't figure out what it was. It's a mineral oil, would be my guess. Not a... Yeah. I think it was like proprietary. I couldn't figure out what it was. It's a special oil. I think only this dude's company

was making them, so I'm pretty sure only he knew. That's awesome. It's just from his like face. He's just wiping his face off. Yeah, he had the perfect face oil. No one else can make it. Were there other projection systems

being used, or was this like in every single sport this was the only thing that could do big projections until the 90s there were like crt projections which just had a like a tube tv inside basically from what i could tell that then shot out the three colors but they couldn't get any bigger than some certain size before the scan lines or whatever were too big. So if you saw like a big live projection before the 90s, that's probably what it was as far as I can tell. I think that they had some LED stuff that they were doing before the 90s.

Oh, okay. I'm old enough now that like when I like went to sports games when I was a kid, like if they used that stuff now still, we'd be like, what is this trash? And we were like, this is amazing. You can look at the replays up on the Jumbotron. All old TV stuff. How could you watch sports on just a regular TV? Oh my God, yeah.

So much better now. Thanks, technology. Now we can enjoy sports better. Sari, can you beat the Eta 4? The Shelby Electric Company in Shelby, Ohio, was a manufacturing company that was established in 1896 and went out of business in 1912. So they didn't last very long. But when they were still operational, they made light bulbs out of hand blown glass. And specifically, they made incandescent bulbs, which run an electric

current through a metal filament so that it glows and it produces heat and light. And then the glass keeps oxygen from reaching the wire so it doesn't oxidize and break down. And the Shelby Electric Company made a variety of bulbs, including a 60 watt model with a carbon containing filament made by a secret process. Nowadays, bulbs have tungsten filaments, which is a conductor. but this mysterious carbon filament was a semiconductor and also eight times thicker than modern light bulbs. The reason why this company is important is because there's something called the centennial light, which is a light bulb that has been basically continuously lit up since June 1901, over 118 years. It is located in Livermore,

California and maintained by the fire department and you can watch it on a live stream there's like a lake you can see it lit up it had a million hours party in 2001 because it's been lit up for so long besides like weird power outages or like one time when someone was watching the stream they were like the light bulb went out they thought it was broken but it was actually like a generator that messed up. Right. Just not getting power. Yeah. So they're not flipping that switch on and off when they leave. Okay. No.

So it's still on and it's instead of 60 watts, which is like the estimated start output of it, it's at about four watts now. So like very dim nightlight. Why is it decreasing in brightness? I have no idea. Something to do with like the decay of the universe, maybe in the metal. Businesses have like studied this to be like, why is this light bulb on for so long? Studied similar models and I couldn't understand why.

So there might be some ideas like the semiconductor material. But that's where my understanding of physics gets wibbly. And some people are just like it could be a manufacturing fluke because these light bulbs are all hand blown. Like something about the combination of the metal and the glass just made this super bulb. But also, another contributing factor is something called planned obsolescence, which is

the sort of stuff conspiracy theories are made of. Big light bulb, so companies like GE, Philips, Tokyo Electric, Germany's Osram, France's Commingles des Lamps or something. I can't. Beautiful.

Yeah, beautiful. Lamp company. Lamp company formed the Phoebus cartel and met in December 1924 to increase light bulb sales by bringing down the lifespan of light bulbs. They used to last over like twenty five hundred hours. lifespan of light bulbs. They used to last over like 2,500 hours. And then all these big light bulb people met and said, we only want our light bulbs to last a thousand hours. And they like really regulated factories so that they did that. And then they like divided up the world into market zones and set sales quotas. Yeah, that's exactly the kind of thing that is definitely illegal. It is what they disbanded in the 1930s.

But like planned obsolescence still affects light bulbs and is now like the basis for a lot of other tech speculation of like bad smartphone batteries. Like is planned obsolescence a thing to make us buy new phones? There's also the conspiracy theory that they all know how to cure cancer but won't tell us because if they cure it, there's no money to be made. Anyway, I hate it. I want like a really old light bulb in my house. I don't care if it's a dim, but I want to be like, this light bulb was passed down for generations. I'm sure it's extremely inefficient.

Yeah, probably. Does turning a light bulb on and off damage the light bulb in an appreciable way? Well, yeah, I don't know. There is some speculation about that. I couldn't find anything for certain. I think it's going to expand and contract and the glass is going to expand and contract

when it gets hot and cold. And it's probably not producing a ton of heat at this point either because it's so dim. Alright, it's time to choose, everybody. Are you ready to choose, Stefan? Yeah, I think so. One, two, three. Sam. Oh, thank you.

I can't resist a cartel. No, literally, that's what they're for. Easily pressured. And now it's time to ask the science couch where we ask listener questions to our couch of finely honed scientific minds, but this time, from the future. Yes. We're here here in 2020 older and wiser

this question is from joseph j nathan how are leds so much more efficient than incandescent bulbs uh if i want to answer this one if i just want to like yank this one out of my butt, I feel like I could do something with it. Should I try, Sari? I think you should try because I, after starting to research this question, I realized how little I knew about light bulbs. Where I was like, oh, they work. And then I started researching it and I was like, oh. The idea of an incandescent bulb is that like you can get a wire really hot and it will glow like hot things glow we know this you can watch your electric stove do it but if you get a thin enough thing of a certain

kind of material hot enough it will glow but this is about making a thing intentionally hot it has to be hot in order to glow and so you are doing doing a lot of heating, which if you've ever had a 100 watt light bulb in your life, you know that they are hot and you cannot just touch them. In fact, I almost burned my dorm room down once. An LED, like the thing it does is make light. Whereas the thing incandescent light does is heat. It is there to get hot so that it will glow. Whereas LED lights are there to glow,

and that is basically all they do. And heat is produced a little bit because of inefficiency, but if it were a perfectly efficient LED, it would produce no heat and all light. I guess I just don't understand how it can make visible light and not make any kind of heat. You could also think of it as an incandescent is like the jankiest way you can make light. Burning stuff is number one. Burning stuff is number one, but it's not far removed from that. We don't know how to make something emit photons besides getting it really super hot and choosing a metal that won't melt at that temperature. Because like some metals, when they heat, they glow red hot and then they start melting and gooping off and so it's like we're gonna find a metal that doesn't become goopy

and instead we can heat so hot that it doesn't only emit infrared light which is like heat with heat vision goggles but it also emits visible light and so we're just gonna like blast as much current through and make it really hot. So LEDs are an electronic component. Like LED stands for a light emitting diode. And a diode is something that you can include in a circuit if you want. Like it's involved in a lot of different electronics besides light bulbs. And it acts as a one-way switch. It's a semiconductor material. So a conductor is something that lets current flow through

and a resistor is something that reduces current flow and a semiconductor is like kind of in between. And semiconductors is where a lot of like the cool electronics material science seems to be. It's like semiconductors are what lets cell phones and computers work and they're part of like switches when you need electronic components to, like, turn things on and off or, like, do some things one way in some circumstances and then some things another way in other circumstances.

Semiconductor materials can be doped. That is a chemical term that chemists use when you mix a material that is mostly one substance and then you sprinkle in another to make it do something weird. And so you take a semiconductor material and you dope it with some other elements, and that creates these things called electron holes, which are basically positively charged atoms, I think, which electrons are attracted to. I think if they're charged, they got to be ions. But other than that. Yeah. Okay. That's good. If I only have one Hank correction in this whole time, I'm doing great.

And so basically when an electron drops from a higher energy level to a lower energy level, it emits a photon. It can be like infrared light, it can be ultraviolet light, or it can be in the visible spectrum that we see. When photons hit our eyes, that's like visible light. And so when electrons are passed through this diode and fall into these holes that are created, then they emit light. And that is what an LED does. It runs electric current it run like pushes electrons through it and then they fall into these holes and then they emit light and that's an led and depending on what the material this like holy semiconductor is made of that lets the electrons

drop in different amounts of energy and different discrete amounts of energy, which creates different colored photons. What? Does it run out of stuff eventually? The stuff is the electrons. So there's always more electrons. Not to worry about running out of those. And then a CFL is also just lighting stuff or heating stuff up really hot. Is that what they do?

No, CFLs are totally a different thing. They do a different thing? They are electrifying gas to create plasma, which then has electrons jumping up and down an energy level to emit the light. And I imagine like the gas in there is hot, but there's not as much gas and it is not as hot or something. I don't know, maybe it's very hot and there's's not as much gas and it is not as hot or something. I don't know. Maybe it's very hot and there's just not as much gas. I think it's not as hot as an incandescent.

I think that is. I know that it's easier to touch. Yeah. I can tell you that. When I was looking up information about this, one source said a filament has to be heated to over 850 Kelvin to emit visible light, which is like very, very hot. And I don't think you'd have to heat a gas because it's already like higher energy than a solid metal just by being gas molecules floating around. So if you could touch a filament, you would really fuck yourself up, basically. Yeah.

Because even if you touch the outside glass nearby the filament that's just heated by radiant heat, you really, like, hurt your hand. Back in the day when you could hurt your hand on a light bulb. Kids these days have it too easy. There are ways that the world's gotten better. You can turn off a light and then unscrew it immediately. This is a wild idea to me from 1998. I just never replaced my light bulbs. You don't have to anymore.

They last forever. They used to burn out every six months. This makes more sense because I was like, I've never experienced this, this like looking up, a light has gone out. I'm so old.

This isn't okay. Okay, bye. We're turning back into old us now. Ah, final Sandbox scores Sari's got one, Sam's got one and Stefan and I come out tied A very symmetrical episode Alright, before we get

to our butt fact, if you like this show and you want to help us out, it's very easy to do that You can leave us a review wherever you listen That helps us know what you like about the show Also, we look to iTunes reviews for topic ideas so if you have any, you can leave those in the reviews. Second, tweet out your favorite moment from the show. And finally, if you want to show your love for SciShow Tangents, just tell people about us.

Thank you for joining. I've been Hank Green. I've been Sari Reilly. I've been Stefan Chin. And I've been Sam Schultz. SciShow Tangents is a co-production of Complexly and the wonderful team at WNYC Studios. It's created by all of us and produced by Caitlin Hoffmeister and Sam Schultz, who also edits a lot of these episodes along with Hiroko Matsushima. Thank you. the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. In 2017, researchers at Rice University bioengineered a strain of E. coli that fluoresces green when exposed to molecules present in inflamed colons.

They fed the E. coli to mice with colitis and measured the amount of green fluorescence present in their poop using a flow cytometer, which is a lab thing, I guess. They found that the more inflamed the mouse's colon was, the greener it glowed. And so they plan to adapt this into like a food additive or something you can take if you have colitis and if you're a human being and not a mouse with colitis, and it would help you monitor your colon health. They would probably change it so it wouldn't glow, but so it would release like a dye, I think is what they were saying. Like your poop would be blue and the bluer it was, the worse shape you were in or something like that.

I love that. I have colitis and I would love to have a better idea of how I'm doing. And I think it'd be great if it glowed. I think it would be more fun if it glowed, yeah. What I want in general is to make it to the point in future

when there is just something that I spit on once a day and it tells me how I am. For the whole your whole body? Just not your butt. The whole thing. You swab both ends and then it tells you how you are. Or you just like or you swallow

a pill it goes all the way through and then when it comes out it's like beep beep beep beep and then you hold your phone over your toilet and it's like beams the information into your phone by airdrop. Do you have to get it out of there? Yeah, do you have to get it? No, you just flush it.

Just flush it. That seems expensive. It's like a beezor where you just eat it over and over again. Uh-huh, you pass down your generational health pill. Here you go, Oren. This has my health for the last 60 years you