WEBVTT - The Future of Artificial Light 0:00:00.160 --> 0:00:07.080 Brought to you by Toyota. Let's go places. Welcome to 0:00:07.280 --> 0:00:14.200 Forward Thinking. Hey there, and welcome to Forward Thinking, the 0:00:14.240 --> 0:00:16.639 podcast that looks at the future and says, I get 0:00:16.680 --> 0:00:19.800 shattered like a lightbulb in an October moon. And I'm 0:00:19.880 --> 0:00:25.240 Jonathan Strickland and I'm Joe McCormick. So today we decided 0:00:25.280 --> 0:00:28.600 we would talk about something that's very important to us 0:00:29.200 --> 0:00:34.040 and really to most people on Earth. Yeah, and that's light. Yeah, 0:00:34.440 --> 0:00:37.959 we actually had a brilliant idea. Oh, light bulb went 0:00:37.960 --> 0:00:41.360 off overhead, and we decided, let's talk about the future 0:00:41.400 --> 0:00:44.440 of light and light bulbs. Kind of a focus on 0:00:44.520 --> 0:00:46.720 light bulbs, but well, we have to get to light bulbs. 0:00:46.800 --> 0:00:48.919 But well we can talk about the future. Really, what 0:00:48.960 --> 0:00:52.800 we mean is focusing on artificial light. Yeah, not just 0:00:53.240 --> 0:00:55.440 light that we can get by waiting around till the 0:00:55.480 --> 0:01:00.000 sun comes up, right, because artificial light is far more 0:01:00.040 --> 0:01:04.240 important and revolutionary to our lives then we often give 0:01:04.280 --> 0:01:07.080 it credit for. I mean, think about all of the 0:01:07.120 --> 0:01:09.880 ways your life would be different if we didn't have 0:01:10.120 --> 0:01:13.679 artificial light. You could only see what was going on 0:01:13.959 --> 0:01:16.039 in the daytime. I would have to make wake up 0:01:16.200 --> 0:01:19.399 much earlier in the morning. Yeah, I would. I would 0:01:19.400 --> 0:01:23.760 have stubbed all of my toes off by now, as 0:01:23.800 --> 0:01:27.520 I just wandered blindly through my house. Yeah, I do 0:01:27.640 --> 0:01:31.600 that with lights, so I just wouldn't have toes anymore. Well, 0:01:31.640 --> 0:01:34.360 I'm of the opinion that the story of artificial light 0:01:34.480 --> 0:01:37.039 is actually one of the most interesting questions we have 0:01:37.240 --> 0:01:42.320 in how humans have co evolved with our technology. Just 0:01:42.360 --> 0:01:46.240 think about the way artificial lighting has changed the way 0:01:46.520 --> 0:01:50.400 humans live and sleep. I mean, number one, it allows 0:01:50.520 --> 0:01:53.200 us to live in places that don't have a lot 0:01:53.240 --> 0:01:55.520 of natural lights, so we can adapt to a much 0:01:55.520 --> 0:02:00.480 more indoor lifestyle. Another thing is that, I know some 0:02:00.520 --> 0:02:04.440 scientists think that humans used to have different sleep patterns 0:02:04.560 --> 0:02:07.560 and we largely have now that back back in the 0:02:07.640 --> 0:02:12.000 days before artificial lighting, bi phasic sleep was very common, 0:02:12.040 --> 0:02:15.280 where you would sleep twice a day in shorter little 0:02:15.320 --> 0:02:18.280 blocks instead of one long sleep at night. Yeah, and 0:02:18.320 --> 0:02:21.240 you would actually spend that time between the sleeps doing 0:02:21.960 --> 0:02:24.480 you know, various things you might be doing, you know, 0:02:24.600 --> 0:02:29.360 actual social visits for example. Right. But as artificial lighting 0:02:29.520 --> 0:02:33.560 indoor lighting became much more common and cheaper and more widespread, 0:02:33.680 --> 0:02:37.280 that just kind of faded away, and now in most 0:02:37.360 --> 0:02:39.240 of the world, it's very common to sleep in just 0:02:39.320 --> 0:02:42.320 one big chunk. Or think about all the ways that 0:02:42.440 --> 0:02:47.919 artificial lighting has made learning easier. Imagine if you weren't 0:02:47.960 --> 0:02:52.920 able to read except like outside in the daytime. Or 0:02:53.000 --> 0:02:55.840 think about all of the other human inventions that would 0:02:55.880 --> 0:02:59.200 be absolutely useless without artificial light. I mean not not 0:02:59.280 --> 0:03:03.160 even including all the ones that use light obviously, like 0:03:03.360 --> 0:03:06.480 we couldn't have our computer screen things like that, yeah, 0:03:06.520 --> 0:03:08.959 if they didn't emit light for us to see. But 0:03:09.160 --> 0:03:13.280 we couldn't have a submarine without artificial light. It's it's 0:03:13.400 --> 0:03:19.040 absolutely fundamental, it's crucial, it's a it's a bedrock of 0:03:19.080 --> 0:03:21.960 all the other technology that we use in our lives. 0:03:22.240 --> 0:03:25.919 I would not be excited about driving a car past dusk, right, 0:03:26.680 --> 0:03:29.720 Oh exactly, Yeah, he didn't have headlights. Yeah, it's it's 0:03:29.720 --> 0:03:32.280 almost ridiculous to try to imagine the world we live 0:03:32.320 --> 0:03:34.440 in without it, and yet it gets no credit. We 0:03:34.440 --> 0:03:37.440 we don't really think to be thankful for artificial light 0:03:37.600 --> 0:03:40.640 very often. It was a big climb to get to 0:03:41.080 --> 0:03:44.120 having artificial light that's as good and as cheap and 0:03:44.200 --> 0:03:47.240 as plentiful as it is today. And it makes me 0:03:47.360 --> 0:03:51.760 wonder what the future is for being able to see 0:03:51.800 --> 0:03:55.240 things artificial light. Yeah, so today we wanted to kind 0:03:55.240 --> 0:03:59.920 of dive into the history of how people have create 0:04:00.040 --> 0:04:01.960 at light and then talk about some of the ways 0:04:02.000 --> 0:04:03.680 that it's that it is going in the future and 0:04:03.960 --> 0:04:07.080 technologies that are up and coming that we're excited about. Yea. Yeah, 0:04:07.320 --> 0:04:11.440 So we obviously had some source of artificial light, even 0:04:11.480 --> 0:04:14.520 if it was pretty crude and not awesome, but we 0:04:14.560 --> 0:04:17.240 had some source as soon as we had fire, Bernie, 0:04:17.480 --> 0:04:22.599 as you may you may refer to. So, yeah, it 0:04:23.279 --> 0:04:27.160 probably wasn't that long after humans discovered fire that they 0:04:27.160 --> 0:04:30.200 started to figure out ways of transporting that fire and 0:04:30.279 --> 0:04:33.400 keeping that fire burning so that they could use as 0:04:33.440 --> 0:04:37.520 a light source. Um. And thus we get to one 0:04:37.520 --> 0:04:42.320 of the earliest forms, the oil lamp. So tell me 0:04:42.320 --> 0:04:44.640 about oil lamps, Jonathan. All Right, So let's say that 0:04:44.680 --> 0:04:48.479 you first you gotta find some form of vessel doesn't 0:04:48.560 --> 0:04:50.919 have to be artificial. You could actually find like maybe 0:04:50.920 --> 0:04:54.000 a shell or a rock that has a kind of 0:04:54.080 --> 0:04:58.560 a hollow a concave area in it, and then you 0:04:59.360 --> 0:05:03.719 put some form of flammable material, let's say moss in it, 0:05:04.400 --> 0:05:08.359 and you then you soak that moss actually in animal fat, 0:05:08.800 --> 0:05:11.359 which would be the oil in this case, and you 0:05:11.480 --> 0:05:14.880 light the fire. The oil and moss together work is 0:05:14.920 --> 0:05:18.040 fuel so that the fire remains lit. You can actually 0:05:18.080 --> 0:05:20.279 move the rock around so that you can carry the 0:05:20.360 --> 0:05:23.200 fire with you. And this is the example of an 0:05:23.240 --> 0:05:28.360 oil lamp. Uh. These date back thousands of years before 0:05:28.400 --> 0:05:32.960 written history. We have found examples of oil lamps. So 0:05:32.960 --> 0:05:35.080 so to like, if you're just not done with your 0:05:35.120 --> 0:05:37.719 cave painting and you really want to get it done tonight, 0:05:37.800 --> 0:05:40.000 you can. Or or if you've gone on one of 0:05:40.040 --> 0:05:45.440 those amazing cave painting wine tours with your fellow cave 0:05:45.520 --> 0:05:49.080 painters and you're going cave to cave and it's getting laid, 0:05:49.240 --> 0:05:51.039 you know, you've got to still be able to see 0:05:51.080 --> 0:05:52.880 before you. You know, you don't want to skip the 0:05:52.960 --> 0:05:54.880 last cave that was the best one. I think, to 0:05:54.880 --> 0:05:58.279 be fair, wine was a little bit after these oil lams. 0:05:58.400 --> 0:06:04.159 I'm w h any The pains were notorious complainers. Another 0:06:04.240 --> 0:06:06.479 thing I'm not so sure about that. We could look 0:06:06.520 --> 0:06:09.000 it up, but I think humans have had alcohol for 0:06:09.040 --> 0:06:12.160 a long long time. But you know, you bring up 0:06:12.200 --> 0:06:15.840 cave paintings, that's another thing. You know, if you don't 0:06:16.000 --> 0:06:18.920 have some source of light that you can carry around 0:06:18.960 --> 0:06:21.479 with you. How do you think these deep internal cave 0:06:21.520 --> 0:06:24.440 paintings were done when people have to be able to 0:06:24.480 --> 0:06:28.440 see their work. Yeah, exactly. So you know what's interesting 0:06:28.480 --> 0:06:30.720 to me is that the oil lamp stuck around from 0:06:30.800 --> 0:06:37.080 prehistory for a really long time. We're talking about seeing 0:06:37.120 --> 0:06:41.000 improvements to the oil lamp made in the eighteen century, 0:06:41.200 --> 0:06:44.680 so so thousands of years here, and that's when I'm 0:06:44.720 --> 0:06:49.039 the are Gone invented a lamp that was more efficient 0:06:49.320 --> 0:06:51.520 and then it consume more of the wick and the oil, 0:06:51.600 --> 0:06:53.800 which meant that you didn't have to trim the wick 0:06:53.839 --> 0:06:57.159 away like the burning wick. Once it was essentially turned 0:06:57.200 --> 0:07:00.560 into carbon, you need to remove it. Um So this 0:07:00.600 --> 0:07:02.919 would be the way of where it was more of 0:07:02.920 --> 0:07:04.520 it was being consumed, so you wouldn't have to trim 0:07:04.560 --> 0:07:07.520 as frequently. Uh So that was a big improvement. But 0:07:07.520 --> 0:07:10.520 oil lamps were eventually replaced it by kerosene lamps in 0:07:10.560 --> 0:07:13.920 the eighteen fifties. Uh nine thousand years ago is when 0:07:13.920 --> 0:07:19.040 we started having wine maybe right, Okay, I was about 0:07:19.080 --> 0:07:22.480 to say, like, when did we start having wine in 0:07:22.480 --> 0:07:26.360 the office. It's kind of awesome. Uh So, but we 0:07:26.480 --> 0:07:29.080 as humans, I got it. But oil lamps were replaced 0:07:29.120 --> 0:07:31.960 by kerosene lamps eighteen fifties, which uses obviously kerosene as 0:07:32.000 --> 0:07:35.480 a fuel and a wick or mantle as the means 0:07:35.520 --> 0:07:39.760 of having the flame. Uh, then we also have gas lamps. 0:07:39.760 --> 0:07:42.000 Now this is kind of interesting. So oil lamps and 0:07:42.080 --> 0:07:46.440 kerosene lamps neither of those were necessarily good for lighting 0:07:46.480 --> 0:07:49.960 something like a street. These were usually small lamps that 0:07:50.000 --> 0:07:52.160 were good to carry around. Like if you ever see 0:07:52.760 --> 0:07:56.840 depictions of a character carrying a small flame lantern around, 0:07:56.920 --> 0:07:59.200 that's probably either an oil lamp or a kerosene lamp. 0:07:59.800 --> 0:08:03.240 But gas lamps used coal gas as fuel, and the 0:08:03.240 --> 0:08:07.240 earliest example I could find dates from sevent two, so 0:08:07.320 --> 0:08:11.880 actually pre dates kerosene lamps. That was when William Murdoch 0:08:12.000 --> 0:08:15.120 used coal gas to light his home as an experiment. 0:08:15.680 --> 0:08:18.600 I guess if you are convinced that your idea is 0:08:18.640 --> 0:08:22.040 gonna work, outfitting your own home with something that could 0:08:22.040 --> 0:08:24.480 potentially kill you is the way to go. So did 0:08:24.560 --> 0:08:27.560 William Murdoch live long enough to be recognized for his achievement? 0:08:27.600 --> 0:08:30.440 He did. He actually eventually outfitted his workplace, which was 0:08:30.480 --> 0:08:33.880 the Soho Foundry, with gas lamps and by the early 0:08:33.920 --> 0:08:36.400 eighteen hundreds, gas lamps would start to become installed in 0:08:36.440 --> 0:08:39.760 several cities in Europe. Baltimore became the first city in 0:08:39.800 --> 0:08:42.319 the United States to have gas lamps, and there are 0:08:42.320 --> 0:08:45.600 other areas other cities in the US that still have 0:08:45.760 --> 0:08:50.120 some gas lamp districts where either the gas lamps were 0:08:50.480 --> 0:08:54.800 rebuilt or preserved um like San Diego as an amazing 0:08:54.840 --> 0:08:58.280 gas lamp district. Uh and gas lamps remained the main 0:08:58.320 --> 0:09:01.199 method of lighting streets and homes until the twentieth century, 0:09:01.200 --> 0:09:03.640 so it stuck around for a good while. But somewhere 0:09:03.760 --> 0:09:06.560 in the meanwhile, all this time, we've been talking about 0:09:06.679 --> 0:09:10.839 burning stuff to create light. What what about this new 0:09:10.880 --> 0:09:14.559 fangled electricity idea that was starting to hit the scene. Yeah, 0:09:14.600 --> 0:09:17.800 there were a lot of people experimenting with it as 0:09:17.880 --> 0:09:21.120 soon as you got volta with a voltaic pile. Once. 0:09:21.240 --> 0:09:23.920 Once that discovery was made, everyone was wondering if there 0:09:23.960 --> 0:09:28.199 could be really cool uses for this discovery. One of 0:09:28.240 --> 0:09:31.400 those people was a British inventor, Humphrey Davy, who in 0:09:31.480 --> 0:09:35.120 eighteen o two connected pair of voltaic piles to pair 0:09:35.160 --> 0:09:38.840 of the charcoal electrodes and an arc of light emitted 0:09:38.880 --> 0:09:41.680 between the two carbon rods. Now, it was not a 0:09:41.679 --> 0:09:44.760 practical source of artificial light because one, it was way 0:09:44.760 --> 0:09:48.559 too bright. You could not use it to light a home. 0:09:49.080 --> 0:09:50.920 It would just be too uncomfortable. The light would be 0:09:50.920 --> 0:09:54.800 too intense. The second problem was it consumed those carbon 0:09:54.880 --> 0:09:58.560 rods very quickly, so before long you would not be 0:09:58.640 --> 0:10:00.640 able to generate light at all. So first it would 0:10:00.640 --> 0:10:02.200 be too much light, and then it'll be no light. 0:10:02.360 --> 0:10:03.839 So it's kind of like trying to light your home 0:10:03.840 --> 0:10:07.200 with a sparkler. Yeah, not not a great not a 0:10:07.240 --> 0:10:10.320 great experience at least not if you're over the age 0:10:10.320 --> 0:10:15.560 of like ten. So uh. Eventually, Williams State would make 0:10:15.679 --> 0:10:19.200 improvements to arc lamps in eighty eight, creating a clockwork 0:10:19.240 --> 0:10:22.400 mechanism that governed the movement of those carbon rods to 0:10:22.600 --> 0:10:25.640 maximize that fuel to consume as much of them as 0:10:25.679 --> 0:10:28.280 possible before the connection was lost. So, in other words, 0:10:28.480 --> 0:10:31.000 it would move the rods in relation to one another 0:10:31.120 --> 0:10:33.640 to try and keep the art going as long as 0:10:33.640 --> 0:10:36.439 it possibly could, and picturing something like a like a 0:10:36.480 --> 0:10:40.120 clockwork spit roast. For I'm not sure if that's what 0:10:40.160 --> 0:10:42.360 it looked like. I have not seen a picture, so 0:10:42.480 --> 0:10:46.880 I'm going to say you were accurate, and I could 0:10:46.880 --> 0:10:51.280 be uncertain of that. Uh So the problem was that 0:10:51.360 --> 0:10:55.480 State's invention was costly, so it didn't really take off either. 0:10:55.840 --> 0:10:59.880 But the the promise of using electricity as a source 0:11:00.040 --> 0:11:03.560 of light in some way remained. Well, when did we 0:11:03.640 --> 0:11:08.280 get the incandescent bulbs that we're also familiar with? That's 0:11:08.320 --> 0:11:10.640 a why did you ask me that question? That's a 0:11:10.679 --> 0:11:15.880 full episode right there, Joe. So incandescent bulbs. The the 0:11:15.960 --> 0:11:18.520 journey to the incandescent bulb was a very long one, 0:11:18.559 --> 0:11:21.320 starting all the way back with Humphrey Davy. But you 0:11:21.840 --> 0:11:26.400 have this progression of various inventors who all worked with 0:11:26.440 --> 0:11:31.080 electricity to try and figure out how to make something incandesce, 0:11:31.960 --> 0:11:34.640 which is all about heat. You heat up a material 0:11:34.880 --> 0:11:38.360 to a temperature high enough to make it glow. That 0:11:39.679 --> 0:11:41.880 is incandescence. That's what we mean when we say an 0:11:41.880 --> 0:11:45.480 incandescent bulb. We're talking about heating up a filament, some 0:11:45.640 --> 0:11:49.200 form of material to a temperature high enough where it 0:11:49.240 --> 0:11:52.160 will glow. It will get hot enough to glow at 0:11:52.200 --> 0:11:56.760 a incredible luminescence so that you can actually see by it. 0:11:57.200 --> 0:12:00.959 So we're talking super hot here, warm Yeah, if you've 0:12:01.000 --> 0:12:03.880 ever touched a light bulb after it had just been 0:12:03.920 --> 0:12:05.679 turned off, you know what I'm talking about. They can 0:12:05.720 --> 0:12:09.120 get super hot, um, and we're the ones we're using 0:12:09.160 --> 0:12:11.520 today are not as hot as some of the earlier 0:12:11.520 --> 0:12:17.240 ones any rate. Uh. The filament is consumed in this process. 0:12:17.360 --> 0:12:19.520 Right as you heat it up, it actually begins to 0:12:19.840 --> 0:12:23.760 essentially burn away. So that means eventually you get to 0:12:23.760 --> 0:12:26.280 a point where the filament is going to break somewhere 0:12:26.400 --> 0:12:30.360 along this connection because it's disintegrated enough. Yeah. Yeah, it's 0:12:30.400 --> 0:12:33.199 essentially there's they're little breaks that that open up until 0:12:33.240 --> 0:12:35.839 there's no longer a connection, Like it just breaks in half, 0:12:36.320 --> 0:12:38.600 or maybe not in half, but somewhere along its length, 0:12:38.920 --> 0:12:40.880 and you have electrodes on either side. Well, now you 0:12:40.880 --> 0:12:44.040 no longer have a pathway for electricity to flow through. 0:12:44.400 --> 0:12:47.080 So that's when the light burns out. That's when you 0:12:47.120 --> 0:12:49.920 get the the dead bulb. If you ever have picked 0:12:49.960 --> 0:12:51.800 up an incandescent ballb after it's burned out and give 0:12:51.840 --> 0:12:53.880 it a little shake and you hear that little tingle tinging, 0:12:54.679 --> 0:12:58.320 that's the that's the broken filament inside just dancing around 0:12:58.360 --> 0:13:01.640 because it's not connected to anything anymore. Uh, so early 0:13:01.640 --> 0:13:05.040 incandescent bulbs were problematic because the filaments burned out at 0:13:05.080 --> 0:13:06.920 a very short time, and it took some time for 0:13:06.960 --> 0:13:09.560 people to figure out how to fix this. One of 0:13:09.559 --> 0:13:12.679 the big developments was, hey, we need to remove the 0:13:12.720 --> 0:13:17.320 filament from oxygen so that it doesn't burn. So that 0:13:17.360 --> 0:13:18.839 means we have to put it in some form of 0:13:18.920 --> 0:13:23.240 container and create a vacuum. So early lightbulbs were put 0:13:23.280 --> 0:13:26.240 in vacuum tubes, but vacuum tube technology was not very 0:13:26.280 --> 0:13:28.960 good in the early nineteenth century. It would not be 0:13:29.080 --> 0:13:33.199 until Thomas Edison came around. Thomas Haysen did not invent 0:13:33.240 --> 0:13:37.000 the lightbulb. No, he is often credited as the inventor 0:13:37.040 --> 0:13:40.000 of the light bulb. He did not. He invented essentially 0:13:40.280 --> 0:13:44.840 the first commercially viable lightbulb, the first one to remain 0:13:45.840 --> 0:13:48.360 working long enough for it to be an actual, you 0:13:48.679 --> 0:13:52.960 useful thing, right. Um So, he started experimenting with a 0:13:53.000 --> 0:13:55.599 couple of different types of filaments and eventually discovered that 0:13:55.640 --> 0:13:59.000 a carbon coated filament and an oxygen free glass bulb 0:13:59.040 --> 0:14:04.240 could last several hours like forty forty hours of light 0:14:04.520 --> 0:14:08.120 before burning out. Uh So, Edison was not the first 0:14:08.120 --> 0:14:10.440 one to make the use of the container free of oxygen. 0:14:10.480 --> 0:14:12.400 Like I said, the other people had other people had 0:14:12.400 --> 0:14:15.440 tried to make vacuum tubes, but Edison's approach was sort 0:14:15.440 --> 0:14:19.760 of the perfection of that art. Uh. The application of 0:14:19.800 --> 0:14:24.440 tungsten um was another big development in this light bulb process, 0:14:24.520 --> 0:14:26.840 tungsten being a metal that has a melting point of 0:14:26.960 --> 0:14:30.600 up to above six thousand degrees fahrenheit, which is something 0:14:30.640 --> 0:14:35.800 around a thirty degrees celsius. And that's high. That's high, 0:14:35.880 --> 0:14:39.480 y'all um. Lots of metals give off mostly heat a 0:14:39.600 --> 0:14:46.680 k A. Infrared photons um when they're electrified, but infrared 0:14:46.800 --> 0:14:49.280 light is invisible and therefore does not help us for 0:14:49.360 --> 0:14:53.120 light bulb purposes. Also, if you get most metals too hot, 0:14:53.200 --> 0:14:57.240 they'll just melt, which is not useful for light bulbs either. 0:14:57.800 --> 0:15:01.200 So uh, you can heat tongue though to a comfortable 0:15:01.280 --> 0:15:06.840 like like four thousand degrees fahrenheit or celsius, and it'll 0:15:06.880 --> 0:15:10.240 stay solid and emit lots of visible light. So when 0:15:10.280 --> 0:15:13.080 I was saying these things get hot, I was not 0:15:13.200 --> 0:15:16.440 kidding quite warm. Yeah, But the thing is that a 0:15:16.520 --> 0:15:18.560 plain old vacuum tube is not the best thing for 0:15:18.640 --> 0:15:21.920 tungsten because when when it heats up like that, it'll 0:15:21.960 --> 0:15:25.320 start shedding atoms that will eventually collect on the inside 0:15:25.360 --> 0:15:27.800 of the bulb, which will darken it over time, which 0:15:27.880 --> 0:15:31.160 again is not conducive to things what you want to 0:15:31.240 --> 0:15:36.160 make light for you. But different gases um in in 0:15:36.160 --> 0:15:40.120 in that vacuum tube, say inert gases, because you don't 0:15:40.240 --> 0:15:46.440 want gasses floating around. And there, yeah, have been different 0:15:46.480 --> 0:15:48.840 gases that are in nert have been experimented with nice 0:15:49.240 --> 0:15:51.000 and one of the things I want to mention also 0:15:51.000 --> 0:15:53.640 were helogen light bulbs. Do you guys have a lot 0:15:53.640 --> 0:15:57.560 of experience with halogen light bulbs, so I'm aware of 0:15:57.600 --> 0:16:00.560 them my house and my house has is crazy. My 0:16:00.640 --> 0:16:04.200 house was made with all these different types of light fixtures, 0:16:04.800 --> 0:16:07.480 no two of which appear to accept the same kind 0:16:07.520 --> 0:16:11.000 of light bulb. So you can imagine how I feel 0:16:11.000 --> 0:16:13.560 whenever a light bulb burns out, like I have to 0:16:13.600 --> 0:16:16.320 go through the closet of light bulbs to find the 0:16:16.400 --> 0:16:19.040 right one. Some of them are halogen light bulbs, so 0:16:19.080 --> 0:16:22.320 they also work through incandescence. They use a tungsten filament 0:16:22.400 --> 0:16:25.600 like Lauren was mentioning, so similar but inside a quartz envelope. 0:16:25.640 --> 0:16:29.200 That's filled with halogen gas. Now, the halogen gas combines 0:16:29.280 --> 0:16:32.160 with the tungsten vapor that's given off while the tungsten 0:16:32.400 --> 0:16:37.040 is incandessing. So while normally the filament would be kind 0:16:37.040 --> 0:16:40.080 of vaporizing away over time until it breaks and then 0:16:40.120 --> 0:16:43.160 your light bulb burns out, in a halogen bulb, it 0:16:43.400 --> 0:16:46.080 that that vapor combines with the halogen gas, and the 0:16:46.080 --> 0:16:50.440 halogen gas will redeposit tungsten on the filament, So it 0:16:50.520 --> 0:16:54.200 preserves the life of the filament. It extends it. It's 0:16:54.240 --> 0:16:58.800 not extended indefinitely. It will still burn out, but it 0:16:58.880 --> 0:17:02.000 does mean that the hall light bulb will remain viable 0:17:02.120 --> 0:17:06.399 longer because of this redepositing. That's so metal. It is 0:17:06.440 --> 0:17:11.000 so metal, so that those are the incandescent bulbs. Well, 0:17:11.040 --> 0:17:13.040 incandescent bulbs are a thing of the past, right, I 0:17:13.040 --> 0:17:15.000 mean that's that's they're more and more places on Earth 0:17:15.000 --> 0:17:17.120 where you are not even allowed to buy them anymore 0:17:17.400 --> 0:17:21.879 for energy efficiency purposes. That's great, though just esthetically it 0:17:21.960 --> 0:17:25.200 is a little sad. I like the globe and incandescent bulb, Yeah, 0:17:25.280 --> 0:17:27.399 they are. They do have a very kind of warm 0:17:27.560 --> 0:17:33.080 glow to the understandably exactly so that they don't live 0:17:33.080 --> 0:17:37.240 as long, and they don't they're not great at energy efficiency. Alright, no, 0:17:37.400 --> 0:17:40.800 they're not more what's better. Well, next, we've got the 0:17:40.800 --> 0:17:44.159 fluorescent bulbs, which have their own issues, but fluoresce and 0:17:44.200 --> 0:17:46.760 bulbs work in a different way. So fluoresce and bulb 0:17:46.800 --> 0:17:50.040 contains a pair of electrodes. So that's similar to an 0:17:50.040 --> 0:17:52.240 incandescent bulb, but instead of you don't have a filament 0:17:52.240 --> 0:17:55.800 in this case, right, you just have you have a 0:17:55.840 --> 0:17:58.760 gas filament. I guess it's not a physical it's not 0:17:58.800 --> 0:18:01.960 like an actual solid filament. I should say is physical? 0:18:02.040 --> 0:18:05.160 Is just gas. So these pair of electrodes. You also 0:18:05.160 --> 0:18:10.040 have some mercury. Uh not freddie mercury, which would be facoless. Yeah, 0:18:10.040 --> 0:18:15.120 don't don't stuff him into vacuum tubes. That's not no, no, uh, 0:18:15.160 --> 0:18:17.640 he's your best friend. So you've got the bit of mercury. 0:18:17.640 --> 0:18:20.080 You've got an inert gas usually are gone, and a 0:18:20.119 --> 0:18:22.639 phosphor powder coating on the inside of the glass. So 0:18:22.640 --> 0:18:25.639 when you turn on a fluorescent lamp, current flows to 0:18:25.800 --> 0:18:29.920 the electrodes. All right. That creates a difference of voltage 0:18:29.920 --> 0:18:34.600 across the two electrodes, and the electron movement excites the mercury. 0:18:34.720 --> 0:18:37.840 Some of that mercury changes from liquid, which is what 0:18:37.960 --> 0:18:41.920 mercury tends to be in room temperature, to a gas. 0:18:41.960 --> 0:18:44.720 So you get collisions between the electrons coming through the 0:18:44.720 --> 0:18:48.680 electrodes uh and the charged particles with the mercury gas atoms. 0:18:48.720 --> 0:18:51.600 That bumps up the electrons to a higher energy level, 0:18:52.280 --> 0:18:55.439 which is how any kind of photon is created. Exactly. 0:18:55.480 --> 0:18:58.600 It's when when an electron returns to its normal energy 0:18:58.640 --> 0:19:01.439 state and being yeah, it has to give off that 0:19:01.560 --> 0:19:05.400 excess energy. Right, So if I if I excite an electron, 0:19:05.440 --> 0:19:07.800 if I energize an electron, so it bumps up to 0:19:07.800 --> 0:19:10.679 a higher energy level and then I stop, Well, then 0:19:10.720 --> 0:19:13.639 the electron is going to return to its normal state 0:19:14.880 --> 0:19:17.080 parties over. Yeah, but then it's like, well, I can't 0:19:17.119 --> 0:19:19.159 carry all this extra energy with me. I gotta get 0:19:19.200 --> 0:19:20.880 rid of it, so it emits it in the form 0:19:20.920 --> 0:19:24.960 of a photon, which is the basic particle of light. However, 0:19:25.400 --> 0:19:28.000 in this case, we're talking about photons and the ultra 0:19:28.080 --> 0:19:31.480 violet range, which means that you and I can't see them, 0:19:31.520 --> 0:19:33.960 and that is where that phosphor cutting comes in. Yeah, 0:19:33.960 --> 0:19:36.120 because in this case, the phosphor coating. What it can 0:19:36.160 --> 0:19:39.639 do is absorbed that ultra violet radiation. It has the 0:19:39.760 --> 0:19:44.000 same sort of uh process where the electrons in the 0:19:44.000 --> 0:19:50.080 fosphor coading get excited. They're like, oh, ultra violet awesome, 0:19:50.160 --> 0:19:52.720 they jump up and then return to normal, but they 0:19:52.880 --> 0:19:56.120 emit light within the visible spectrum. So it's it's kind 0:19:56.160 --> 0:19:58.800 of like it's like a step by step process of 0:19:58.800 --> 0:20:01.360 trying to get light from the visible light from this 0:20:01.640 --> 0:20:05.280 from this approach. And that's exactly how these things work. 0:20:05.760 --> 0:20:10.359 So it's pretty cool. Um, literally, much cooler. Yeah, it 0:20:10.400 --> 0:20:13.200 doesn't involve in condessing. Of course, now we live in 0:20:13.240 --> 0:20:16.120 the age of the L E ED bol yes, and 0:20:16.440 --> 0:20:20.000 this is kind of a game changer in a way. Yeah, so, 0:20:20.160 --> 0:20:21.840 I mean L E d s also still have a 0:20:21.840 --> 0:20:23.800 lot of challenges, but I'll cover that in a second. 0:20:24.160 --> 0:20:28.080 Light emitting diodes also, that's what LED stands for, and 0:20:28.119 --> 0:20:31.800 they are taught type of solid state lighting or s 0:20:31.800 --> 0:20:34.720 s L. So solid state sounds pretty cool. You're like, 0:20:34.720 --> 0:20:37.360 all right, so how does this thing work? Well, we 0:20:37.520 --> 0:20:42.560 have to talk about semi conductors again. I know, I'm sorry. No, 0:20:42.720 --> 0:20:46.000 we love talking about semi conductors. I love talking about them. 0:20:46.200 --> 0:20:49.400 I wish I had a truly deep understanding of them. 0:20:49.440 --> 0:20:52.600 I have a basic level understanding of semi conductor technology, 0:20:52.680 --> 0:20:55.360 maybe a little beyond basic, But I always every time 0:20:55.400 --> 0:20:57.560 I go into this, I'm always like, am I explaining 0:20:57.640 --> 0:21:01.040 this correctly? So with semiconductors you have You're doing great, 0:21:01.440 --> 0:21:05.600 thank you. You have positively charged sections, negatively charged sections. 0:21:06.000 --> 0:21:09.840 So the negatively charged area of the semiconductor has an 0:21:09.880 --> 0:21:13.120 excess of electrons. That's what creates the negative charge. Right, 0:21:13.600 --> 0:21:16.879 the positively charged section we call uh we say that 0:21:16.880 --> 0:21:19.520 it has holes. In other words, it has the capacity 0:21:19.600 --> 0:21:22.879 to accept electrons. Okay, so it has the ability to 0:21:22.960 --> 0:21:25.679 create a flow from one side to the other. Yeah. You. 0:21:25.920 --> 0:21:28.199 It essentially says, hey, you know, if you got electron 0:21:28.280 --> 0:21:30.280 sent them on over because I got some space, dude, 0:21:30.359 --> 0:21:32.520 I mean like we can totally crash over here. I 0:21:32.560 --> 0:21:35.280 need a roomy rent is high. You know. It's kind 0:21:35.320 --> 0:21:38.200 of like living in San Francisco. So in this case, 0:21:39.160 --> 0:21:42.240 you also have an area in between the two where 0:21:42.760 --> 0:21:45.280 you it's a mixture kind of. You have the holes 0:21:45.280 --> 0:21:48.320 and you have electrons. The electrons fill the first adjacent 0:21:48.400 --> 0:21:51.639 line of holes, and unless you give more energy to 0:21:51.640 --> 0:21:55.600 the negative side. UH, it reaches a level of equilibrium 0:21:55.640 --> 0:21:59.960 where there's kind of a barrier between the the pete 0:22:00.040 --> 0:22:03.040 hype that's the positive side, and the N type that's 0:22:03.080 --> 0:22:07.160 the negative side UH material in the semiconductor, and that 0:22:07.480 --> 0:22:11.480 area in between is called the depletion zone, which I 0:22:11.680 --> 0:22:14.280 like to think is where you send Superman villains if 0:22:14.280 --> 0:22:18.920 the negative zone fills up. UM. So when you introduce 0:22:18.960 --> 0:22:22.000 electricity to the semiconductor on the inside of the material, 0:22:22.080 --> 0:22:25.119 the electrons are pushed from the negative side to the 0:22:25.119 --> 0:22:29.520 positive side. They can overcome the depletion zone. Now when 0:22:29.560 --> 0:22:32.080 they get to the positive side, they enter the holes. 0:22:32.119 --> 0:22:34.520 The holes are at a lower energy level than the 0:22:34.560 --> 0:22:38.320 electrons the excited electrons are, so the electrons move into 0:22:38.359 --> 0:22:42.040 the holes, they emit that excess of energy in the 0:22:42.080 --> 0:22:44.399 form of a photon, just as we were talking about 0:22:44.400 --> 0:22:48.199 with the fluorescent bulbs, and thus you get light. And 0:22:48.359 --> 0:22:51.359 this flow, by the way, only works in one direction. Diodes, 0:22:51.680 --> 0:22:55.320 that's a very important electronic component, and that's the that's 0:22:55.359 --> 0:22:58.159