1 00:00:02,520 --> 00:00:05,520 Speaker 1: Get in touch with technologies with tech Stuff from how 2 00:00:05,559 --> 00:00:13,880 Speaker 1: stuff works dot com. Hello again, everyone in Welcome to 3 00:00:14,320 --> 00:00:16,640 Speaker 1: tech Stuff. My name is Chris Poulette and I am 4 00:00:16,640 --> 00:00:19,120 Speaker 1: an editor at how stuff works dot com. Sitting across 5 00:00:19,120 --> 00:00:23,200 Speaker 1: from me, well as usual, but dancing this time, his 6 00:00:23,320 --> 00:00:26,720 Speaker 1: senior writer, Jonathan Strickland. Hey, there, I just looked up 7 00:00:26,760 --> 00:00:30,240 Speaker 1: and there he was doing that thing, getting my getting 8 00:00:30,240 --> 00:00:32,920 Speaker 1: my energy up. Actually, one of the things that uh, 9 00:00:33,200 --> 00:00:35,879 Speaker 1: you know, we start the episode off pretty traditionally. One 10 00:00:35,880 --> 00:00:38,720 Speaker 1: of the things that we had as an early ritual 11 00:00:38,840 --> 00:00:41,200 Speaker 1: as we recorded Tech Stuff was Jonathan and I would 12 00:00:41,240 --> 00:00:45,120 Speaker 1: be sitting here in the virtual darkness and someone we 13 00:00:45,159 --> 00:00:47,400 Speaker 1: had different engineers over the time, over the years now, 14 00:00:47,440 --> 00:00:49,600 Speaker 1: but someone would come in and turn on the lights 15 00:00:50,000 --> 00:00:56,680 Speaker 1: and good lighted begs. But we wanted to talk a 16 00:00:56,680 --> 00:01:00,480 Speaker 1: little bit about light, specifically light bulbs to day. So 17 00:01:00,600 --> 00:01:03,760 Speaker 1: what a brilliant idea of those were? You know, before lightbulbs, 18 00:01:04,480 --> 00:01:07,120 Speaker 1: Before light bulbs, there was no way to indicate that 19 00:01:07,160 --> 00:01:12,600 Speaker 1: you had an idea. Yeah, yeah, there's no there's no yeah, 20 00:01:13,120 --> 00:01:16,199 Speaker 1: pre light bulb there was no ting before we get 21 00:01:16,280 --> 00:01:20,039 Speaker 1: into how light bulbs work in their history and everything. 22 00:01:20,040 --> 00:01:22,360 Speaker 1: I want to lay down a little physics for you. 23 00:01:22,560 --> 00:01:27,520 Speaker 1: All right, go ahead and enlighten us. I see, So 24 00:01:27,680 --> 00:01:30,920 Speaker 1: we are talking about light and what is light. Well, 25 00:01:31,000 --> 00:01:35,080 Speaker 1: light is made up of these very tiny particle like 26 00:01:35,560 --> 00:01:41,880 Speaker 1: packets called photons. They've got energy, they have momentum, but 27 00:01:42,160 --> 00:01:46,000 Speaker 1: there's one thing they do not have charge accounts mass 28 00:01:47,880 --> 00:01:51,040 Speaker 1: or I was going they have no mass, but not 29 00:01:51,200 --> 00:01:55,640 Speaker 1: no moss. Photons are these packets of energy. They have 30 00:01:55,760 --> 00:01:59,960 Speaker 1: momentum but not mass. And these particles, these these photons 31 00:02:00,680 --> 00:02:06,200 Speaker 1: are emitted by atoms. Once you have excited an atom 32 00:02:06,280 --> 00:02:09,600 Speaker 1: to the point where it's electron starts to move out 33 00:02:09,639 --> 00:02:14,560 Speaker 1: of its normal orbit and goes into a further orbit 34 00:02:14,639 --> 00:02:18,360 Speaker 1: from the atoms nucleus. And once once you remove the 35 00:02:18,480 --> 00:02:22,360 Speaker 1: energy source from that atom, the electron will eventually return 36 00:02:22,480 --> 00:02:25,840 Speaker 1: to its normal orbit around the nucleus. But it has 37 00:02:25,880 --> 00:02:29,800 Speaker 1: to it has to get rid of that energy that 38 00:02:29,960 --> 00:02:33,440 Speaker 1: you have pushed into it. Right, Energy is not created 39 00:02:33,520 --> 00:02:37,639 Speaker 1: or destroyed, it's just transferred. So this electron, as it's 40 00:02:37,680 --> 00:02:39,919 Speaker 1: coming back down to its normal orbital is going to 41 00:02:40,080 --> 00:02:43,560 Speaker 1: shed off energy, and in this case the energy is 42 00:02:43,560 --> 00:02:48,240 Speaker 1: in the form of photons. Now, photons are going to 43 00:02:48,320 --> 00:02:52,600 Speaker 1: be emitted in the entire spectrum of light. Now humans 44 00:02:53,080 --> 00:02:56,800 Speaker 1: we are capable of perceiving a narrow band of that 45 00:02:56,919 --> 00:03:03,040 Speaker 1: spectrum called the visible spectrum because it's visible to us. Oh, 46 00:03:03,240 --> 00:03:05,120 Speaker 1: I always wondered about that. This is where the whole 47 00:03:05,200 --> 00:03:08,639 Speaker 1: ROYGBIV thing comes in, right. The different wavelengths of light 48 00:03:08,760 --> 00:03:12,760 Speaker 1: dictate what the color is as we perceive it. Uh. 49 00:03:12,840 --> 00:03:16,320 Speaker 1: The but the the light goes well beyond outside the 50 00:03:16,320 --> 00:03:19,360 Speaker 1: the visible range. There's things like ultra violet and infrared, 51 00:03:19,440 --> 00:03:22,880 Speaker 1: and then you get into electromagnetic radiation as you go 52 00:03:22,960 --> 00:03:27,280 Speaker 1: further out. But and anyway, Uh, these photons can come 53 00:03:27,320 --> 00:03:32,960 Speaker 1: into various forms, so you can have a infrared photon 54 00:03:33,240 --> 00:03:36,600 Speaker 1: or ultra violet photons. So uh, if it's in the 55 00:03:36,640 --> 00:03:39,160 Speaker 1: visible light spectrum, we're able to see it. Now that's 56 00:03:39,200 --> 00:03:44,720 Speaker 1: important because that's the whole basis of creating a light bulb. 57 00:03:44,760 --> 00:03:47,480 Speaker 1: As you want to create some sort of device that 58 00:03:48,040 --> 00:03:52,720 Speaker 1: you can used to create photons so that you can 59 00:03:52,760 --> 00:03:56,720 Speaker 1: illuminate an area. And before light bulbs, you didn't really 60 00:03:56,760 --> 00:03:59,560 Speaker 1: have that option unless you set something on fire. Uh. 61 00:03:59,600 --> 00:04:01,560 Speaker 1: And there's a limited number of things we can set 62 00:04:01,560 --> 00:04:04,480 Speaker 1: on fire before we set ourselves on fire, or we 63 00:04:04,560 --> 00:04:07,440 Speaker 1: run out of stuff that is flammable, So it was 64 00:04:07,480 --> 00:04:09,720 Speaker 1: a good idea to try and develop something that could 65 00:04:10,160 --> 00:04:15,600 Speaker 1: create light in another way. Now, uh, how do we 66 00:04:15,680 --> 00:04:19,520 Speaker 1: know about how what is the principle upon which light 67 00:04:19,520 --> 00:04:24,760 Speaker 1: bulbs work. Well, again, if you excite an atom and 68 00:04:24,920 --> 00:04:27,880 Speaker 1: you push those electrons out, when the electrons come back in, 69 00:04:27,960 --> 00:04:33,160 Speaker 1: they emit photons. If you give enough energy to an object, 70 00:04:33,760 --> 00:04:37,240 Speaker 1: then you can emit enough uh photons for it to 71 00:04:37,279 --> 00:04:39,960 Speaker 1: be within the depending upon the nature of that material, 72 00:04:40,080 --> 00:04:43,039 Speaker 1: for it to be within the visible spectrum for it 73 00:04:43,080 --> 00:04:47,000 Speaker 1: to be perceptible. Because even if it's in the visible spectrum, 74 00:04:47,040 --> 00:04:50,359 Speaker 1: if the energy is not great enough, you won't be 75 00:04:50,400 --> 00:04:53,839 Speaker 1: able to see it. And we're all emitting energy all 76 00:04:53,880 --> 00:04:57,320 Speaker 1: the time, like humans are emitting infrared energy all the time, 77 00:04:57,360 --> 00:04:59,120 Speaker 1: and if you had an infrared camera, you'd be able 78 00:04:59,160 --> 00:05:02,160 Speaker 1: to see it even in perfectly dark room. You look 79 00:05:02,240 --> 00:05:04,400 Speaker 1: at the infrared camera, look at a person, you would 80 00:05:04,440 --> 00:05:07,839 Speaker 1: see light as interpreted by the sensor in that camera 81 00:05:08,040 --> 00:05:10,520 Speaker 1: and converted to visible light for us to see. You 82 00:05:10,520 --> 00:05:12,920 Speaker 1: would be able to see that person because they're emitting 83 00:05:12,920 --> 00:05:17,359 Speaker 1: that infrared light. Well, we may even depending on what what, 84 00:05:17,520 --> 00:05:21,160 Speaker 1: depending on the material, it may even be emitting visible light. 85 00:05:21,200 --> 00:05:23,760 Speaker 1: But it might be emitting at levels so low as 86 00:05:23,800 --> 00:05:27,440 Speaker 1: to be imperceptible to humans. So if you add more energy, 87 00:05:27,680 --> 00:05:31,920 Speaker 1: you can boost that and actually see the visible light. Uh. 88 00:05:32,040 --> 00:05:35,560 Speaker 1: And this can happen with things like solid materials. And 89 00:05:35,600 --> 00:05:39,839 Speaker 1: there was a fellow named John William Draper who in 90 00:05:39,960 --> 00:05:44,920 Speaker 1: eighty seven demonstrated that solid materials, almost all of them, 91 00:05:45,040 --> 00:05:50,440 Speaker 1: will glow once they reach a temperature of seven kelvin. 92 00:05:51,960 --> 00:05:56,000 Speaker 1: Kelvin's a scientific scale for temperatures. Kelvin is what we 93 00:05:56,120 --> 00:05:59,800 Speaker 1: have when you get to zero kelvin. That says that 94 00:06:00,080 --> 00:06:02,520 Speaker 1: as cold as you can get, it actually refers to 95 00:06:02,560 --> 00:06:06,400 Speaker 1: molecular movement, and at zero kelvin, there is no molecular movement. 96 00:06:07,160 --> 00:06:11,559 Speaker 1: So that's like the deepest depths of space where there's 97 00:06:11,760 --> 00:06:16,520 Speaker 1: nothing absolutely absolutely uh So, if you wanted to convert 98 00:06:16,600 --> 00:06:19,520 Speaker 1: that into degrees that we're more familiar with most of 99 00:06:19,600 --> 00:06:22,440 Speaker 1: us anyway, it would be about five and twenty five 100 00:06:22,480 --> 00:06:26,800 Speaker 1: degrees celsius or nine seventy seven degrees fahrenheit, And at 101 00:06:26,800 --> 00:06:30,479 Speaker 1: that temperature solid materials will start to glow. We call 102 00:06:30,520 --> 00:06:34,320 Speaker 1: it the Draper point. Now, in order to have a 103 00:06:35,000 --> 00:06:38,840 Speaker 1: object glow at a uh at a at an intensity 104 00:06:38,920 --> 00:06:41,719 Speaker 1: bright enough for it to illuminate, say a room, you 105 00:06:41,760 --> 00:06:45,279 Speaker 1: will have to put in more energy than that, right, 106 00:06:45,400 --> 00:06:47,560 Speaker 1: because this is talking about they start to glow, but 107 00:06:47,600 --> 00:06:49,440 Speaker 1: that doesn't mean that they're glowing so brightly as to 108 00:06:49,480 --> 00:06:52,960 Speaker 1: illuminate an entire room. That's where it starts. So but 109 00:06:53,040 --> 00:06:54,880 Speaker 1: you know, you've you've probably seen this. If you've ever 110 00:06:54,880 --> 00:06:58,400 Speaker 1: seen a blacksmith work, then you know the blacksmith might 111 00:06:58,400 --> 00:07:00,240 Speaker 1: be heating up iron and when they take that out 112 00:07:00,320 --> 00:07:05,279 Speaker 1: it's glowing red. Or a glass blower or lava. You know, 113 00:07:05,320 --> 00:07:09,200 Speaker 1: there's lots of stuff that tends to lava. It's not 114 00:07:09,279 --> 00:07:12,280 Speaker 1: all manmade, but there's lots of stuff out there that 115 00:07:12,440 --> 00:07:17,600 Speaker 1: um that that demonstrates this. So that's the principle. But 116 00:07:17,600 --> 00:07:23,160 Speaker 1: but the idea behind an electric light source actually predates 117 00:07:23,280 --> 00:07:28,920 Speaker 1: Draper's discovery. Really yes, back in well the early eighteen hundreds. 118 00:07:28,920 --> 00:07:31,800 Speaker 1: I've seen I've seen reports from eighteen o six all 119 00:07:31,840 --> 00:07:35,080 Speaker 1: the way up to eighteen o nine. There's some discrepancies there. 120 00:07:35,560 --> 00:07:40,800 Speaker 1: But an English chemist and inventor named Sir Humphrey Davy, 121 00:07:41,400 --> 00:07:44,280 Speaker 1: named Humphrey Davy, he was designated a night So that's 122 00:07:44,320 --> 00:07:50,080 Speaker 1: the sir. He connected a battery to a strip of charcoal, 123 00:07:51,000 --> 00:07:53,680 Speaker 1: and he used the electricity to actually heat up the 124 00:07:53,760 --> 00:07:56,640 Speaker 1: charcoal to the point where it started to glow, which 125 00:07:56,680 --> 00:08:02,360 Speaker 1: created technically the first electric arc lamp. Uh. This was 126 00:08:02,440 --> 00:08:09,040 Speaker 1: not a viable means of illumination as it was hard 127 00:08:09,080 --> 00:08:11,120 Speaker 1: to do. It required a lot of energy. The battery 128 00:08:11,200 --> 00:08:13,640 Speaker 1: drained really quickly, the carbon burned at such a or 129 00:08:14,680 --> 00:08:21,160 Speaker 1: it got so hot as to be incredibly dangerous for uh, say, 130 00:08:21,200 --> 00:08:24,200 Speaker 1: I don't know a typical house um. So it was 131 00:08:24,240 --> 00:08:27,520 Speaker 1: not something that was going to immediately be adopted into 132 00:08:27,560 --> 00:08:33,640 Speaker 1: every household, but it was proving a concept. Uh. Also, 133 00:08:33,840 --> 00:08:36,000 Speaker 1: by the way, Sir Humphrey Davy did go on to 134 00:08:36,120 --> 00:08:39,280 Speaker 1: invent many things, including the Davy lamp, which was not 135 00:08:39,760 --> 00:08:42,679 Speaker 1: an electrical lamp. It was a gas lamp. There was 136 00:08:42,720 --> 00:08:45,360 Speaker 1: a gas lamp that had a mesh screen that would 137 00:08:45,400 --> 00:08:51,040 Speaker 1: surround the flame so that miners meaning people who mind 138 00:08:51,120 --> 00:08:55,120 Speaker 1: the earth, not people who are underage miners, could take 139 00:08:55,200 --> 00:08:58,640 Speaker 1: the lamps, although depending in England at that point in time, 140 00:08:58,880 --> 00:09:02,240 Speaker 1: the two may have been the same. Aim. Hey, our 141 00:09:02,320 --> 00:09:04,880 Speaker 1: history has not always been a nice one. But the 142 00:09:04,920 --> 00:09:09,240 Speaker 1: miners could take a lamp down below the ground, and 143 00:09:09,280 --> 00:09:11,720 Speaker 1: even if they encountered a pocket of gas. The mesh 144 00:09:11,760 --> 00:09:15,440 Speaker 1: would actually, this fine mesh would prevent the gas and 145 00:09:15,480 --> 00:09:19,080 Speaker 1: the flame from making friends and becoming a big boom. 146 00:09:19,840 --> 00:09:24,720 Speaker 1: Very important for miners of both types. So the he 147 00:09:24,800 --> 00:09:27,160 Speaker 1: did invent that, Again not electrical, but I thought it 148 00:09:27,200 --> 00:09:30,920 Speaker 1: was an interesting aside. Moving ahead back in the eighty one, 149 00:09:32,520 --> 00:09:38,360 Speaker 1: Frederick de Moulins, and I'm sure I have completely mispronounced 150 00:09:38,360 --> 00:09:41,559 Speaker 1: his name, and I apologized profusely for that. Another Englishman, 151 00:09:42,800 --> 00:09:45,400 Speaker 1: Yeah it could be. He patented a light bulb in 152 00:09:45,520 --> 00:09:47,880 Speaker 1: eight forty one, and this one was comprised of a 153 00:09:47,920 --> 00:09:51,200 Speaker 1: glass case and a burner or burners actually made of 154 00:09:51,280 --> 00:09:58,400 Speaker 1: carbon and in expensive material you may know as platinum. Yeah, 155 00:09:58,440 --> 00:10:01,800 Speaker 1: you thought that led light bulbs were expensive, so uh 156 00:10:02,200 --> 00:10:06,720 Speaker 1: he he patented that design. Again not really practical for 157 00:10:07,400 --> 00:10:12,960 Speaker 1: for every day or even industrial use. An American inventor 158 00:10:13,080 --> 00:10:15,560 Speaker 1: named J. W. Starr received a patent for a light 159 00:10:15,559 --> 00:10:19,559 Speaker 1: bulb that used a carbon burner. Um and then the 160 00:10:19,600 --> 00:10:23,120 Speaker 1: next few decades were spent among inventors trying to find 161 00:10:23,120 --> 00:10:27,160 Speaker 1: a way to perfect the discoveries these earlier inventors had found, 162 00:10:27,960 --> 00:10:32,440 Speaker 1: so that you could create a light bulb that made sense, 163 00:10:33,320 --> 00:10:37,000 Speaker 1: that that was efficient, that could light well, that was 164 00:10:37,040 --> 00:10:40,400 Speaker 1: not going to be prohibitively expensive. And there are two 165 00:10:40,520 --> 00:10:44,360 Speaker 1: names in particular that pop up all the time, one 166 00:10:44,400 --> 00:10:48,160 Speaker 1: of them being probably the most famous uh connected to 167 00:10:48,200 --> 00:10:51,720 Speaker 1: the light bulb, which is Thomas Edison. Yes, it's funny, 168 00:10:51,880 --> 00:10:54,560 Speaker 1: as we were recording this, we are rapidly approaching the 169 00:10:54,760 --> 00:10:59,400 Speaker 1: hundred thirty third anniversary of the first test of Edison's 170 00:10:59,440 --> 00:11:02,800 Speaker 1: incandescent light bulb. Yeah. Now, it is important to note 171 00:11:03,000 --> 00:11:05,520 Speaker 1: Edison was not the person who invented the light bulb. 172 00:11:05,600 --> 00:11:07,960 Speaker 1: He was not even the person to invent the incandescent 173 00:11:08,120 --> 00:11:11,760 Speaker 1: light bulb, but he was someone who perfected that design 174 00:11:11,800 --> 00:11:16,600 Speaker 1: and made it viable as an actual product. Yeah. Now, 175 00:11:16,679 --> 00:11:22,200 Speaker 1: it's it's important to note, um that these these early lightbulbs, uh, 176 00:11:22,280 --> 00:11:25,400 Speaker 1: you know, not only were homes not really wired. Actually, 177 00:11:25,480 --> 00:11:27,720 Speaker 1: the light bulb, I would argue, based on my research 178 00:11:28,120 --> 00:11:31,760 Speaker 1: the over the past, you know, the past times that 179 00:11:31,760 --> 00:11:34,000 Speaker 1: we've done tech stuff, we've talked about Edison and Tesla 180 00:11:34,040 --> 00:11:36,920 Speaker 1: and the lightbulb actually was sort of the key to 181 00:11:37,000 --> 00:11:41,120 Speaker 1: getting homes wired for electricity. Yeah, I mean you and 182 00:11:41,200 --> 00:11:44,360 Speaker 1: it made sense because suddenly you had households that could 183 00:11:44,440 --> 00:11:50,400 Speaker 1: be uh safely with air quotes around that lit after 184 00:11:50,480 --> 00:11:56,160 Speaker 1: dark and extend the useful uh time human being could 185 00:11:56,240 --> 00:12:01,000 Speaker 1: get stuff done, because otherwise, when night fell, we might 186 00:12:01,040 --> 00:12:03,240 Speaker 1: as well just go to bed because it was gonna 187 00:12:03,280 --> 00:12:05,800 Speaker 1: be pretty dark. Well, you know, we're early to bed 188 00:12:05,800 --> 00:12:08,360 Speaker 1: and early to rise, as they say, early to bed, 189 00:12:08,360 --> 00:12:11,040 Speaker 1: early to rise, because otherwise you're barking your ship on 190 00:12:11,080 --> 00:12:14,559 Speaker 1: the coffee table. Well, yeah, that's that's true. Well, gas lamps, 191 00:12:14,679 --> 00:12:18,839 Speaker 1: uh were very very popular. But they were I mean, 192 00:12:18,880 --> 00:12:24,079 Speaker 1: in addition to being obviously inherently somewhat dangerous um and 193 00:12:24,160 --> 00:12:29,840 Speaker 1: oil lamps, but they were um smoky, um. They were dirty, 194 00:12:30,320 --> 00:12:33,559 Speaker 1: so you know, I'm sure they probably didn't smell all 195 00:12:33,600 --> 00:12:36,440 Speaker 1: that great um. But the problem with these early light 196 00:12:36,480 --> 00:12:40,120 Speaker 1: bulbs is that they weren't very practical. O. Hey, look 197 00:12:40,120 --> 00:12:43,320 Speaker 1: I got yeah, well, so much for that one. Another one. 198 00:12:43,360 --> 00:12:47,480 Speaker 1: There was another inventor, an Englishman. The Englishman named Sir 199 00:12:47,600 --> 00:12:50,640 Speaker 1: Joseph Swan, who was working on light bulbs around the 200 00:12:50,679 --> 00:12:54,880 Speaker 1: same time as Edison. And Swan's bulb used carbonized paper 201 00:12:55,040 --> 00:12:58,040 Speaker 1: as the burner, which worked pretty well except that it 202 00:12:58,080 --> 00:13:01,280 Speaker 1: didn't last terribly long. And in fact, this was a 203 00:13:01,280 --> 00:13:05,679 Speaker 1: problem that a lot of lightbulb. Researchers were encountering that, 204 00:13:06,559 --> 00:13:09,520 Speaker 1: including Edison. The first problem was, all right, well, we've 205 00:13:09,559 --> 00:13:13,160 Speaker 1: we found uh that if you if you run enough 206 00:13:13,200 --> 00:13:16,760 Speaker 1: electricity through some sort of object, you can heat it 207 00:13:16,800 --> 00:13:20,720 Speaker 1: up enough so that it begins to glow. But if 208 00:13:20,800 --> 00:13:26,600 Speaker 1: that item is exposed to oxygen, then it will burn. 209 00:13:27,320 --> 00:13:29,320 Speaker 1: So even if you found a material that does not 210 00:13:29,600 --> 00:13:32,240 Speaker 1: melt at a high temperature, it would burn, it would 211 00:13:32,280 --> 00:13:35,040 Speaker 1: combust at a high enough temperature because it'd be you know, 212 00:13:35,320 --> 00:13:37,839 Speaker 1: it would be adjacent to oxygen, which you know that 213 00:13:38,000 --> 00:13:41,040 Speaker 1: that's part of the fuel you need, you know, in 214 00:13:41,120 --> 00:13:45,360 Speaker 1: order to have a fire. UM. So the you had 215 00:13:45,360 --> 00:13:47,280 Speaker 1: to close it off from oxygen, which is why they 216 00:13:47,280 --> 00:13:49,920 Speaker 1: were these these vacuum tubes essentially is what they create, 217 00:13:50,000 --> 00:13:56,840 Speaker 1: these vacuum containers. UM. But once they got through that, 218 00:13:56,880 --> 00:13:59,760 Speaker 1: they had to find what's the right material to use. Actually, 219 00:13:59,800 --> 00:14:05,040 Speaker 1: what Edison ended up using at first was bamboo. He 220 00:14:05,120 --> 00:14:10,880 Speaker 1: took Japanese bamboo and carbonized it and created a filament. 221 00:14:11,320 --> 00:14:14,840 Speaker 1: In this case, what a filament is is this really long, long, long, 222 00:14:14,880 --> 00:14:18,960 Speaker 1: long strip of material that is then coiled so that 223 00:14:19,080 --> 00:14:23,720 Speaker 1: you can decrease the space that it needs to um 224 00:14:23,920 --> 00:14:26,280 Speaker 1: to fit into whatever you want to put it in, 225 00:14:26,560 --> 00:14:29,360 Speaker 1: so it's got a lot of surface areas. Then the 226 00:14:29,440 --> 00:14:35,080 Speaker 1: resistance is high. A resistance in electricity is the the 227 00:14:35,120 --> 00:14:38,400 Speaker 1: materials resistance to electrons flowing through it freely. The more 228 00:14:38,440 --> 00:14:41,400 Speaker 1: resistance there is in general, Okay, you've got greater resistance, 229 00:14:41,440 --> 00:14:44,520 Speaker 1: you have greater heat. Well, the secret to the light 230 00:14:44,600 --> 00:14:46,680 Speaker 1: here is the amount of heat that's being generated. That's 231 00:14:46,680 --> 00:14:50,800 Speaker 1: the energy that is creating this whole system of electrons 232 00:14:50,880 --> 00:14:53,080 Speaker 1: being pushed out and then when they start coming back in, 233 00:14:53,120 --> 00:14:57,520 Speaker 1: the photons are being let out. So let let the 234 00:14:57,520 --> 00:15:01,120 Speaker 1: photons out? Who let the photons out? That was as 235 00:15:01,160 --> 00:15:03,960 Speaker 1: an a swan as it turns out. Um, it's interesting 236 00:15:03,960 --> 00:15:07,480 Speaker 1: because then Edison Edison ended up hiring what his first 237 00:15:07,560 --> 00:15:11,560 Speaker 1: his first light bulb design used a temperature controlled switch 238 00:15:12,280 --> 00:15:17,080 Speaker 1: to try and keep the material at the right temperature 239 00:15:17,120 --> 00:15:21,080 Speaker 1: so that it would the light bulb would remain lit longer. 240 00:15:21,120 --> 00:15:23,280 Speaker 1: Because that was an early problem with these light bulbs 241 00:15:23,360 --> 00:15:26,280 Speaker 1: is that their their utility was low because they couldn't 242 00:15:26,280 --> 00:15:29,240 Speaker 1: you couldn't burn them for very long. But this was 243 00:15:29,280 --> 00:15:33,480 Speaker 1: a problem because the the temperature control controlled switch, once 244 00:15:33,480 --> 00:15:36,160 Speaker 1: a certain temperature was hit, it would switch off right, 245 00:15:36,280 --> 00:15:38,800 Speaker 1: the light would go off, and so it started creating 246 00:15:38,800 --> 00:15:43,120 Speaker 1: this flickering problem and made the bulb practically unusable. So 247 00:15:43,160 --> 00:15:47,480 Speaker 1: he then hired a physicist from Princeton named Francis Upton, 248 00:15:47,920 --> 00:15:52,920 Speaker 1: who led Edison's research team working on light bulbs, to 249 00:15:53,200 --> 00:15:55,800 Speaker 1: start practicing with other stuff. That's when they came upon 250 00:15:55,880 --> 00:15:59,440 Speaker 1: the idea of using the bamboo as a filament. Um. 251 00:15:59,680 --> 00:16:02,880 Speaker 1: Swan and Edison ended up battling each other. Edison ended 252 00:16:02,960 --> 00:16:07,120 Speaker 1: up taking patent lawsuits against Swan, but then ultimately the 253 00:16:07,120 --> 00:16:10,960 Speaker 1: two of them formed a partnership together and they created 254 00:16:10,960 --> 00:16:17,160 Speaker 1: the Edison Swan United Company. Teamwork, teamwork. Um. Yeah, just so, 255 00:16:17,480 --> 00:16:19,840 Speaker 1: just so you guys know, patent wars are not a 256 00:16:19,880 --> 00:16:24,240 Speaker 1: new thing. Oh no, not in the least. Um. Yeah, 257 00:16:24,440 --> 00:16:27,520 Speaker 1: it's funny. While u while carbonized bamboo sounds like an 258 00:16:27,640 --> 00:16:32,600 Speaker 1: ingredient for a hipster sandwich, Um, it did have the 259 00:16:32,640 --> 00:16:38,400 Speaker 1: ability to burn for more than which you know, back 260 00:16:38,400 --> 00:16:40,720 Speaker 1: in that time, that was pretty nice for a for 261 00:16:40,720 --> 00:16:45,040 Speaker 1: a light bulb. Yeah, and uh, this served as the 262 00:16:45,080 --> 00:16:47,760 Speaker 1: basis for what future light bulbs would be. And then 263 00:16:48,400 --> 00:16:51,440 Speaker 1: we ended up shifting to a different type of filament. 264 00:16:51,480 --> 00:16:52,960 Speaker 1: But we'll get into that in a second. So let's 265 00:16:53,000 --> 00:16:58,240 Speaker 1: talk about the basic anatomy of an incandescent light bulb. 266 00:16:58,280 --> 00:17:00,600 Speaker 1: And don't worry Floresce in an L. E. D. Fans, 267 00:17:00,920 --> 00:17:03,600 Speaker 1: We're gonna get to you too. You just sit tight. 268 00:17:04,359 --> 00:17:09,520 Speaker 1: So the incandescent bulb, You've got two contacts to two 269 00:17:09,600 --> 00:17:13,880 Speaker 1: electrical context on this on a typical incandescent bulb. One 270 00:17:13,920 --> 00:17:16,000 Speaker 1: of them is at the very end of the bulb, 271 00:17:16,359 --> 00:17:19,960 Speaker 1: that's the base of the bulb, and the other is 272 00:17:20,000 --> 00:17:25,000 Speaker 1: in the actual treads that you screw into your um 273 00:17:25,400 --> 00:17:29,560 Speaker 1: light bulb socket. Yeah. Actually usually has a squeaky noise 274 00:17:29,600 --> 00:17:33,320 Speaker 1: which has that perfect pitch to give me the heavy gbs. 275 00:17:33,840 --> 00:17:35,960 Speaker 1: It's like the fingernails on the chalkboard type thing. It's 276 00:17:35,960 --> 00:17:39,160 Speaker 1: like almost every single light bulb in my house makes 277 00:17:39,160 --> 00:17:44,639 Speaker 1: that noise. And so it's a physically demanding task for 278 00:17:44,720 --> 00:17:47,840 Speaker 1: me because well, I guess psychologically really more than physically, 279 00:17:47,840 --> 00:17:52,200 Speaker 1: because because I I suffer trauma. One follows the other. 280 00:17:53,440 --> 00:17:55,119 Speaker 1: How many how many Jonathans does it take to you 281 00:17:55,440 --> 00:17:58,200 Speaker 1: screw in a light bulb? Yeah, well, after the first one, 282 00:17:58,240 --> 00:18:01,800 Speaker 1: it takes a few others to common down. Yeah, I'm 283 00:18:01,840 --> 00:18:03,920 Speaker 1: not afraid of the dark. I'm just afraid of changing 284 00:18:04,000 --> 00:18:06,879 Speaker 1: light bulbs, so that's not really true. I just don't 285 00:18:06,920 --> 00:18:09,520 Speaker 1: like doing it. But anyway, these mental contacts are what 286 00:18:09,840 --> 00:18:14,720 Speaker 1: create the the circuit, right, so that the circuits complete. 287 00:18:14,760 --> 00:18:19,119 Speaker 1: When these two contacts are are in contact with the 288 00:18:19,160 --> 00:18:24,000 Speaker 1: rest of the electrical system. On um, the contacts are 289 00:18:24,000 --> 00:18:28,159 Speaker 1: attached to some wires and those wires are attached to 290 00:18:28,280 --> 00:18:31,960 Speaker 1: the filament. Now, in this case, the filament is no 291 00:18:32,040 --> 00:18:36,160 Speaker 1: longer bamboo. For your typical incandescent bulb, it's usually tungsten. 292 00:18:36,800 --> 00:18:40,040 Speaker 1: And the reason why it's tungsten is a couple of 293 00:18:40,080 --> 00:18:43,160 Speaker 1: different reasons. One is that the melting temperature of tungsten 294 00:18:43,359 --> 00:18:47,160 Speaker 1: is really high, so you can heat tungsten up quite 295 00:18:47,160 --> 00:18:51,480 Speaker 1: a bit and not worry about it being um melting 296 00:18:51,480 --> 00:18:54,640 Speaker 1: away that. That's obviously another issue with light bulbs. Right 297 00:18:54,680 --> 00:18:57,399 Speaker 1: you heat up materials, some material is gonna melt, and 298 00:18:57,440 --> 00:19:00,280 Speaker 1: it might melt before you hit that draper point, which 299 00:19:00,320 --> 00:19:02,720 Speaker 1: would be bad because you wouldn't get any light out 300 00:19:02,720 --> 00:19:05,600 Speaker 1: of it. You would just get a you know, a 301 00:19:05,680 --> 00:19:10,760 Speaker 1: glass cylinder of hot molten sludge. Um Hot molten sludge 302 00:19:10,760 --> 00:19:13,640 Speaker 1: would be a great name for a band. It is, uh. 303 00:19:13,840 --> 00:19:16,960 Speaker 1: It is, however, very thin the filament is very thin. 304 00:19:17,040 --> 00:19:20,920 Speaker 1: As anyone who has uh smacked a light bulb hard 305 00:19:21,040 --> 00:19:23,760 Speaker 1: enough to break the filament but not hard enough to 306 00:19:23,800 --> 00:19:27,560 Speaker 1: break the glass knows that's really annoyed. That's another really 307 00:19:27,600 --> 00:19:32,480 Speaker 1: annoying thing about changing lightbulbs. Oh when did I yeah, 308 00:19:32,720 --> 00:19:35,680 Speaker 1: just ruined a perfectly good bye bulbs. So, yeah, it's 309 00:19:35,760 --> 00:19:39,440 Speaker 1: very thin. Again, that's to increase resistance. That's another thing, 310 00:19:39,480 --> 00:19:44,920 Speaker 1: is that a a a copper wire, for example, the 311 00:19:44,920 --> 00:19:47,800 Speaker 1: the greater the diameter of a copper wire, the lower 312 00:19:47,840 --> 00:19:53,000 Speaker 1: the resistance. So if you have a very um thin 313 00:19:53,119 --> 00:19:55,679 Speaker 1: copper wire, the resistance is greater. That means it's going 314 00:19:55,680 --> 00:19:57,639 Speaker 1: to also generate more heat as a result. Well, this 315 00:19:57,760 --> 00:20:00,760 Speaker 1: tungusten same thing. I mean, this same principle applies across 316 00:20:00,800 --> 00:20:04,960 Speaker 1: all materials. U tungsten filament is very very very thin. 317 00:20:05,440 --> 00:20:09,240 Speaker 1: It's actually coiled twice. The first coil is done to 318 00:20:09,520 --> 00:20:13,240 Speaker 1: decrease it's you know, the length, and then after you've 319 00:20:13,240 --> 00:20:16,639 Speaker 1: coiled it once, you coil it a second time around. Uh. 320 00:20:16,680 --> 00:20:22,159 Speaker 1: These these support wires, and uh that helps when the 321 00:20:23,280 --> 00:20:26,600 Speaker 1: tungsten heats up, it starts to generate, you know, give 322 00:20:26,640 --> 00:20:30,760 Speaker 1: off these photons. Uh, it helps, Uh, concentrate that light 323 00:20:31,000 --> 00:20:33,240 Speaker 1: so that you have enough for it to be useful, 324 00:20:33,280 --> 00:20:36,040 Speaker 1: because again, you want to give enough energy there for 325 00:20:36,119 --> 00:20:38,360 Speaker 1: you to have visible light that you can actually see 326 00:20:38,400 --> 00:20:40,600 Speaker 1: stuff by, but you don't want to have to pour 327 00:20:40,640 --> 00:20:43,120 Speaker 1: in more energy than was necessary. And we should point 328 00:20:43,160 --> 00:20:47,639 Speaker 1: out incandescent bulbs not terribly efficient. No, we think about 329 00:20:47,840 --> 00:20:52,680 Speaker 1: heat being a a wasted form of energy in this case, 330 00:20:53,160 --> 00:20:56,160 Speaker 1: and how hot and incandescent bulb gets. And it's also 331 00:20:56,200 --> 00:21:01,520 Speaker 1: giving out photons outside the range of visible light, so 332 00:21:01,640 --> 00:21:04,800 Speaker 1: you're getting you know, infrared light and maybe even ultraviolet 333 00:21:04,840 --> 00:21:07,680 Speaker 1: light from from these light bulbs. Well that that means 334 00:21:07,680 --> 00:21:10,400 Speaker 1: that again it's a drop in efficiency. I mean, yeah, 335 00:21:10,440 --> 00:21:12,399 Speaker 1: it's giving off light, but we can't see it, so 336 00:21:12,440 --> 00:21:15,000 Speaker 1: it doesn't do us any good, not not in a 337 00:21:15,080 --> 00:21:19,040 Speaker 1: normal application. Anyway. You know, if you're doing something that 338 00:21:19,280 --> 00:21:22,159 Speaker 1: required infrared or ultraviolet light, than sure, although there are 339 00:21:22,160 --> 00:21:25,880 Speaker 1: better ways of doing that than using a regular incandescent lightbulb. Yeah, 340 00:21:25,920 --> 00:21:28,560 Speaker 1: I mean you you could. You could even cook brownies 341 00:21:28,600 --> 00:21:32,240 Speaker 1: with it, which is with an easy bake oven. It's 342 00:21:32,240 --> 00:21:35,720 Speaker 1: funny because I don't think people, not everyone realizes this. 343 00:21:35,960 --> 00:21:39,439 Speaker 1: It's not like a secret. But um, the the older 344 00:21:39,480 --> 00:21:42,040 Speaker 1: easy bake ovens, especially they're they're essentially using the heat 345 00:21:42,080 --> 00:21:45,280 Speaker 1: from a lightbulb to cook uh, you know, very simple 346 00:21:46,240 --> 00:21:50,080 Speaker 1: cakes and brownies and things like that. Right now, the 347 00:21:51,080 --> 00:21:53,840 Speaker 1: you know, you might ask what's inside a lightbulb? Besides 348 00:21:53,960 --> 00:21:56,720 Speaker 1: all this stuff, there's actually a gas that's inside most 349 00:21:56,760 --> 00:21:59,280 Speaker 1: incandescent light bulbs, and it's usually are gone, which is 350 00:21:59,280 --> 00:22:01,679 Speaker 1: an uh it's an inert gas, meaning it does not 351 00:22:01,800 --> 00:22:06,199 Speaker 1: react to other stuff. Hey, are gone gas. It's a 352 00:22:06,200 --> 00:22:10,960 Speaker 1: tornado outside. So like, oh, you never do anything now 353 00:22:11,040 --> 00:22:14,360 Speaker 1: that you want it to be inert because obviously, like 354 00:22:14,560 --> 00:22:17,640 Speaker 1: something like oxygen, then the tungsten would start to burn. 355 00:22:18,320 --> 00:22:23,199 Speaker 1: It would dramatically decrease the life lifespan of your average 356 00:22:23,280 --> 00:22:26,360 Speaker 1: light bulb. So they pump the oxygen, They pump air 357 00:22:26,440 --> 00:22:29,600 Speaker 1: out of the glass globe and fill it with our 358 00:22:29,680 --> 00:22:33,000 Speaker 1: gone gas. Yep. And so you might say, well, why 359 00:22:33,080 --> 00:22:35,760 Speaker 1: why not just have a vacuum inst of our gone gas. 360 00:22:36,080 --> 00:22:39,840 Speaker 1: The reason for that is that, uh, at that high temperature, 361 00:22:39,960 --> 00:22:42,400 Speaker 1: you have another problem besides combustion, even if you don't 362 00:22:42,400 --> 00:22:46,679 Speaker 1: have oxygen, the other problem is evaporation. Atoms from the 363 00:22:46,720 --> 00:22:51,000 Speaker 1: tungsten will actually evaporate off the filament. Because of those 364 00:22:51,040 --> 00:22:54,240 Speaker 1: high temperatures, and over time, that means that you're losing 365 00:22:54,359 --> 00:22:56,240 Speaker 1: you know, every time you're using that light bulb, you're 366 00:22:56,280 --> 00:23:00,480 Speaker 1: losing tungsten with the old light bulber. Yeah, and with 367 00:23:00,520 --> 00:23:03,000 Speaker 1: the old light bulbs, you would actually have the tungsten 368 00:23:03,119 --> 00:23:06,040 Speaker 1: start to evaporate away and coat the inside of the 369 00:23:06,080 --> 00:23:08,119 Speaker 1: light bulbs, So the light bulb would get more and 370 00:23:08,160 --> 00:23:11,480 Speaker 1: more dim both because there was less filament to light 371 00:23:11,880 --> 00:23:14,200 Speaker 1: and because all the filament that was gone is now 372 00:23:14,240 --> 00:23:17,200 Speaker 1: coating the inside of the light bulb making it darker. 373 00:23:17,600 --> 00:23:20,840 Speaker 1: So uh, by using argon, what it actually acts as 374 00:23:20,880 --> 00:23:23,920 Speaker 1: is sort of a sort of a barrier. These atoms 375 00:23:23,960 --> 00:23:29,679 Speaker 1: from tungsten will come off the filament, bump into a 376 00:23:29,680 --> 00:23:33,360 Speaker 1: an argon atom, and then because argon's a nerd, it's 377 00:23:33,359 --> 00:23:37,040 Speaker 1: not going to act with that that um uh energy 378 00:23:37,160 --> 00:23:40,240 Speaker 1: or that that particle. Rather, the particle then returns to 379 00:23:41,720 --> 00:23:46,280 Speaker 1: the strip of tungsten um. So it acts as kind 380 00:23:46,320 --> 00:23:49,880 Speaker 1: of a cushion. It's just pushing the the atoms back 381 00:23:50,000 --> 00:23:53,280 Speaker 1: to the tungsten. Keeping that filament last to last longer 382 00:23:54,280 --> 00:23:58,280 Speaker 1: very important. And so that's the basic premise behind these 383 00:23:58,359 --> 00:24:02,280 Speaker 1: incandescent bulbs. The a uh, you know, they get to 384 00:24:02,320 --> 00:24:07,919 Speaker 1: a pretty hot temperature. We're talking around degrees celsius or 385 00:24:07,960 --> 00:24:12,560 Speaker 1: four thousand degrees fahrenheit um, because again you want to 386 00:24:12,560 --> 00:24:14,719 Speaker 1: put out enough visible light for it to be useful. 387 00:24:14,920 --> 00:24:19,680 Speaker 1: Now that all depends on the wattage of the bulb. Yeah, 388 00:24:19,800 --> 00:24:23,639 Speaker 1: which generally speaking, you can think of his brightness. Um, 389 00:24:23,680 --> 00:24:27,360 Speaker 1: it's it's kind of or or really you can think 390 00:24:27,359 --> 00:24:30,560 Speaker 1: of his brightness or how hot that tungsten's getting inside 391 00:24:30,560 --> 00:24:35,880 Speaker 1: the light bulb. That's what that kind of translates into. 392 00:24:36,359 --> 00:24:38,720 Speaker 1: Uh and uh. Interesting. We have an article on the 393 00:24:38,760 --> 00:24:41,879 Speaker 1: site how light Bulbs Work and how stuff Works dot com. 394 00:24:42,119 --> 00:24:45,840 Speaker 1: Great article, great illustrations, a fun read. I mean, I 395 00:24:46,200 --> 00:24:48,600 Speaker 1: really do mean that. It's actually you would think it's 396 00:24:48,600 --> 00:24:50,520 Speaker 1: an article about light bulbs, but it really is a 397 00:24:50,520 --> 00:24:54,560 Speaker 1: fun read. And one of my favorite uh facts in 398 00:24:54,600 --> 00:24:58,399 Speaker 1: this is that a typical sixty what bulb has a 399 00:24:58,440 --> 00:25:02,560 Speaker 1: tungsten filament that six and a half feet or two 400 00:25:02,600 --> 00:25:06,480 Speaker 1: meters long and one hundred of an inch thick. I 401 00:25:06,480 --> 00:25:10,439 Speaker 1: don't have the centimeters for that, sorry, but it's you know, 402 00:25:10,760 --> 00:25:12,879 Speaker 1: six and a half feet long or two meters and 403 00:25:13,000 --> 00:25:17,160 Speaker 1: if you were to completely uncoil that filament, however, once 404 00:25:17,200 --> 00:25:21,840 Speaker 1: it's all double coiled. It's in a space that's shorter 405 00:25:21,960 --> 00:25:25,359 Speaker 1: than you know, the tip of your pinkie finger, and 406 00:25:25,400 --> 00:25:28,200 Speaker 1: you're thinking, wow, that's to go from six and a 407 00:25:28,240 --> 00:25:32,480 Speaker 1: half feet to that is pretty impressive, you know. And 408 00:25:32,520 --> 00:25:35,280 Speaker 1: again that's packing all that material in so it can 409 00:25:35,320 --> 00:25:38,600 Speaker 1: give off enough light for it to be useful. Yeah, 410 00:25:38,800 --> 00:25:41,680 Speaker 1: now do you uh, do you happen to know how 411 00:25:41,840 --> 00:25:45,400 Speaker 1: three way light bulbs work? I do not. Actually, as 412 00:25:45,440 --> 00:25:47,760 Speaker 1: a matter of fact, we have another very very short 413 00:25:47,880 --> 00:25:50,359 Speaker 1: article on how three way light bulbs work and it 414 00:25:50,480 --> 00:25:54,080 Speaker 1: they also have to filaments. Um, it's it's very interesting. 415 00:25:54,080 --> 00:25:58,480 Speaker 1: Now the socket has to accommodate that because it has 416 00:25:58,520 --> 00:26:01,840 Speaker 1: to do also with a connect on the outside. But 417 00:26:02,240 --> 00:26:04,960 Speaker 1: essentially what happens is that the socket is, you know, 418 00:26:05,040 --> 00:26:08,720 Speaker 1: through a switch, providing instructions on which of the two 419 00:26:08,760 --> 00:26:14,080 Speaker 1: filaments to light. So for the first on switch, if 420 00:26:14,119 --> 00:26:15,800 Speaker 1: you've ever used the three way light, you know that 421 00:26:15,880 --> 00:26:18,680 Speaker 1: the first one is the lowest setting uses the least 422 00:26:18,680 --> 00:26:21,600 Speaker 1: amount of electricity. Well, the one filament that is designed 423 00:26:21,640 --> 00:26:26,159 Speaker 1: for that lower setting comes on when you click the switch. Again, 424 00:26:26,520 --> 00:26:29,480 Speaker 1: that provides instructions for the second filament, but only the 425 00:26:29,480 --> 00:26:32,240 Speaker 1: second filament to come on, and then the third the 426 00:26:32,320 --> 00:26:35,480 Speaker 1: two team up. I see so, and then that the 427 00:26:35,520 --> 00:26:38,200 Speaker 1: next is off. Got you. You get these the sum 428 00:26:38,280 --> 00:26:40,720 Speaker 1: total of light coming from the bulb, which is if 429 00:26:40,720 --> 00:26:43,560 Speaker 1: your pardon upon a brilliant weight. I do that because 430 00:26:43,560 --> 00:26:47,440 Speaker 1: it's very simple, shiny. So moving on. That's a little 431 00:26:47,560 --> 00:26:50,120 Speaker 1: just aside and firefly reference for you guys out there. 432 00:26:50,240 --> 00:26:52,679 Speaker 1: And of course you can achieve different effects to with 433 00:26:52,720 --> 00:26:54,840 Speaker 1: the kind of glass. You might be wondering, you know 434 00:26:54,880 --> 00:26:58,159 Speaker 1: that the what the natural lighting or the what does 435 00:26:58,200 --> 00:27:00,560 Speaker 1: the blue what's the blue one do? Well, it's just 436 00:27:01,280 --> 00:27:06,159 Speaker 1: diffusing the uh photons given off by the tungusten inside 437 00:27:06,160 --> 00:27:08,399 Speaker 1: the light bulb a little bit different. And I should 438 00:27:08,400 --> 00:27:11,159 Speaker 1: point out an eat that depending upon the material you're using, 439 00:27:11,200 --> 00:27:14,200 Speaker 1: that will determine what kind of light is given off. Right, 440 00:27:14,320 --> 00:27:18,199 Speaker 1: So tungstens giving off this light uh, partially because of 441 00:27:18,640 --> 00:27:21,760 Speaker 1: the fact that it's tungsten, But other materials give off 442 00:27:21,840 --> 00:27:24,480 Speaker 1: different kinds of light, different colors of light along or 443 00:27:24,680 --> 00:27:29,560 Speaker 1: or essentially lights that are different wavelengths, right, so different 444 00:27:29,600 --> 00:27:32,760 Speaker 1: parts of the spectrum, sometimes visible, sometimes not. Uh. This 445 00:27:32,880 --> 00:27:35,880 Speaker 1: is used in chemistry, it's used in astronomy, it's used 446 00:27:35,920 --> 00:27:38,239 Speaker 1: in lots of different areas of physics, not just in 447 00:27:38,400 --> 00:27:41,840 Speaker 1: creating light bulbs or you know, heating stuff up until 448 00:27:41,840 --> 00:27:46,720 Speaker 1: it glows. But that kind of that's kind of the 449 00:27:46,880 --> 00:27:49,359 Speaker 1: full discussion on incandescent bulbs. But those aren't the only 450 00:27:49,400 --> 00:27:56,280 Speaker 1: kind of bulbs we have. We also have fluorescent bulbs. Yes, um, 451 00:27:56,400 --> 00:28:00,639 Speaker 1: you might say, well, you know, uh, Edison and later 452 00:28:00,920 --> 00:28:05,080 Speaker 1: the company that he was directly slash indirectly the founder 453 00:28:05,119 --> 00:28:08,640 Speaker 1: of General Electric, you know, perfected the incandescent light bulb 454 00:28:08,840 --> 00:28:11,560 Speaker 1: and uh uh you know, you would think that they 455 00:28:11,560 --> 00:28:14,440 Speaker 1: would be very upset that the fluorescent came out. Well 456 00:28:15,040 --> 00:28:17,879 Speaker 1: not really because, as we touched on on our famous 457 00:28:18,240 --> 00:28:23,240 Speaker 1: or infamous GE series how how the famous that's more, 458 00:28:23,359 --> 00:28:26,560 Speaker 1: that's the famous series on G E G E was 459 00:28:26,600 --> 00:28:29,840 Speaker 1: actually in development of the fluorescent light bulb. Yeah, so 460 00:28:29,960 --> 00:28:34,800 Speaker 1: fluorescent lightbulbs use a different method of generating lights, so 461 00:28:35,000 --> 00:28:38,760 Speaker 1: you're not you don't have that physical filament inside a 462 00:28:38,760 --> 00:28:43,120 Speaker 1: fluorescent bulb. Instead, what you have as a sealed glass tube. 463 00:28:43,200 --> 00:28:45,680 Speaker 1: By the way, we also have how fluorescent lamps work 464 00:28:46,720 --> 00:28:49,440 Speaker 1: at how stuff works dot com. So again you should 465 00:28:49,480 --> 00:28:52,400 Speaker 1: read that if you're interested to learn all the physics 466 00:28:52,440 --> 00:28:55,840 Speaker 1: involved in this. But in general, you've got a sealed 467 00:28:55,920 --> 00:28:58,840 Speaker 1: glass tube and not the animal that Chris was alluding 468 00:28:58,880 --> 00:29:03,600 Speaker 1: to earlier. It's just completely sealed. Uh. The tube has 469 00:29:03,680 --> 00:29:07,720 Speaker 1: inside it's some mercury and there's also an inert gas 470 00:29:07,760 --> 00:29:12,640 Speaker 1: like again are gone. Uh. The inside of this glass 471 00:29:12,680 --> 00:29:18,720 Speaker 1: tube is coated with a powder that's phosphorus. Now, phosphorus 472 00:29:18,800 --> 00:29:23,200 Speaker 1: means that when light strikes it, it gives off light. 473 00:29:24,480 --> 00:29:29,200 Speaker 1: So that sounds like it could be totally useless, except 474 00:29:29,320 --> 00:29:33,880 Speaker 1: we're talking about light within the entire spectrum. So even 475 00:29:34,080 --> 00:29:37,080 Speaker 1: if if you have a certain kind of phosphor, it 476 00:29:37,160 --> 00:29:40,360 Speaker 1: will um If you were to hit that phosphor with 477 00:29:40,480 --> 00:29:43,640 Speaker 1: light that's outside the visible spectrum, for example, ultraviolet light, 478 00:29:45,000 --> 00:29:48,240 Speaker 1: and then that phosphor actually emits visible light, that becomes 479 00:29:48,320 --> 00:29:51,920 Speaker 1: useful because you can either look at stuff that is 480 00:29:52,040 --> 00:29:56,120 Speaker 1: in the presence of light that's otherwise outside our our 481 00:29:56,520 --> 00:29:59,800 Speaker 1: field of vision, or you can create something like of 482 00:30:00,080 --> 00:30:03,880 Speaker 1: or escent light bulb that uses light outside of our 483 00:30:03,960 --> 00:30:06,680 Speaker 1: vision to create light that's inside our vision. The way 484 00:30:06,720 --> 00:30:10,000 Speaker 1: this works is you've got the electrodes at either end 485 00:30:10,040 --> 00:30:13,680 Speaker 1: of this tube, uh that are wired to some sort 486 00:30:13,720 --> 00:30:16,120 Speaker 1: of circuit. Now, the circuit once we turn that on 487 00:30:16,760 --> 00:30:21,520 Speaker 1: starts to introduce uh, free flowing electrons into the gas. Now, 488 00:30:21,520 --> 00:30:25,680 Speaker 1: this is different from the filament approach because then you 489 00:30:25,760 --> 00:30:30,320 Speaker 1: have electrons running through a material directly right, just like 490 00:30:30,400 --> 00:30:32,160 Speaker 1: you would a wire in a circuit. I mean, that's 491 00:30:32,240 --> 00:30:36,360 Speaker 1: essentially what it is with this. It's free flowing electrons 492 00:30:36,440 --> 00:30:40,240 Speaker 1: going through uh. The gas in this case are gone. 493 00:30:40,800 --> 00:30:42,840 Speaker 1: It takes a little while for these electrons to be 494 00:30:42,880 --> 00:30:46,479 Speaker 1: introduced into this this tube, which is why when you 495 00:30:46,640 --> 00:30:50,160 Speaker 1: turn on most fluorescent light bulbs there's this little flickering 496 00:30:50,200 --> 00:30:54,680 Speaker 1: moment while it's coming on. Yea because the cause again, 497 00:30:54,800 --> 00:30:58,520 Speaker 1: the the has to introduce the the free flowing electrons 498 00:30:58,560 --> 00:31:04,200 Speaker 1: for this to work. So once these electrons with considerable 499 00:31:04,280 --> 00:31:08,440 Speaker 1: voltage are introduced, uh, the energy starts to change some 500 00:31:08,520 --> 00:31:14,640 Speaker 1: of the mercury that's in that tube from liquid to gas. Now, again, 501 00:31:15,320 --> 00:31:20,040 Speaker 1: when we're introducing electricity into or energy into an atom, 502 00:31:20,080 --> 00:31:24,080 Speaker 1: it's exciting those electrons, pushing them out of their orbitals uh. 503 00:31:24,160 --> 00:31:26,080 Speaker 1: And then when the electrons start to come back down 504 00:31:26,080 --> 00:31:29,720 Speaker 1: to their normal orbital they'll give off photons. With the 505 00:31:29,720 --> 00:31:34,400 Speaker 1: case of mercury, you're talking about light photons that are 506 00:31:34,400 --> 00:31:38,720 Speaker 1: in the ultra violet wavelength range. So again you can 507 00:31:39,040 --> 00:31:42,200 Speaker 1: you you're exciting the mercury and it's giving off ultraviolet light. 508 00:31:43,160 --> 00:31:47,719 Speaker 1: We can't see ultra violet light unaided anyway, We're incapable 509 00:31:47,720 --> 00:31:51,240 Speaker 1: of seeing light at that wavelength. But by coding the 510 00:31:51,280 --> 00:31:54,880 Speaker 1: inside of that tube with phosphors that are able to 511 00:31:54,960 --> 00:31:57,960 Speaker 1: absorb ultra violet light and then emit light in the 512 00:31:58,040 --> 00:32:01,920 Speaker 1: visible spectrum, we can use that tra violet light two 513 00:32:02,480 --> 00:32:06,040 Speaker 1: give us light we can see indirectly. We have this 514 00:32:06,200 --> 00:32:11,680 Speaker 1: intermediary step with the phosphors, So the mercury starts to 515 00:32:11,760 --> 00:32:15,680 Speaker 1: go from liquid to gas, gives off these ultra violet photons. 516 00:32:15,680 --> 00:32:18,960 Speaker 1: The vultraviolet photons hit the phosphors, the phosphors absorbed the 517 00:32:19,160 --> 00:32:21,840 Speaker 1: ultraviolet light and emit light in the visible spectrum, and 518 00:32:22,120 --> 00:32:26,320 Speaker 1: voila or viola if you prefer, we have ourselves a 519 00:32:26,360 --> 00:32:28,040 Speaker 1: fluorescent light bulb. By the way, if you have a 520 00:32:28,080 --> 00:32:31,760 Speaker 1: black light, you essentially have a fluorescent bulb that does 521 00:32:31,800 --> 00:32:35,720 Speaker 1: not have those phosphors necessarily on the inside because it's 522 00:32:35,760 --> 00:32:39,760 Speaker 1: just emitting the ultra violet light directly. Uh And then 523 00:32:39,800 --> 00:32:43,760 Speaker 1: you can have those wicked uh Van posters light up 524 00:32:43,760 --> 00:32:48,200 Speaker 1: in pretty colors. All in all, You're just another brick 525 00:32:48,240 --> 00:32:53,240 Speaker 1: in the wall, thank you. So, uh yeah, I mean 526 00:32:53,280 --> 00:32:56,040 Speaker 1: that's the that's the essential way that fluorescence work. And 527 00:32:56,120 --> 00:32:59,080 Speaker 1: this is also why because they contain mercury why they 528 00:32:59,120 --> 00:33:05,520 Speaker 1: are so dangerous or potentially dangerous, because mercury is toxic. 529 00:33:06,160 --> 00:33:09,960 Speaker 1: And if you were to, say, I don't know, drop 530 00:33:09,960 --> 00:33:14,120 Speaker 1: a palette of fluorescent lightbulbs in a warehouse, you could 531 00:33:14,160 --> 00:33:17,600 Speaker 1: have a potentially dangerous situation on your hands because you 532 00:33:17,640 --> 00:33:22,960 Speaker 1: could very much have enough mercury there to suffer mercury poisoning. Yeah, 533 00:33:23,000 --> 00:33:27,520 Speaker 1: it's some. It's in a way sort of amusing that 534 00:33:28,000 --> 00:33:33,479 Speaker 1: so many of my friends remember busting fluorescent lightbulbs fondly 535 00:33:33,520 --> 00:33:35,800 Speaker 1: because they make out. They make a loud noise. I 536 00:33:35,920 --> 00:33:39,920 Speaker 1: had one. I was in a bookstore once when, uh 537 00:33:40,000 --> 00:33:43,080 Speaker 1: and I was just perusing some books, so I'm very 538 00:33:43,120 --> 00:33:46,640 Speaker 1: much focused on what I'm doing when the employee behind me, 539 00:33:46,760 --> 00:33:50,520 Speaker 1: who was trying to change out a fluorescent bulb, accidentally 540 00:33:50,600 --> 00:33:54,320 Speaker 1: dropped the one in her hands from a ladder and 541 00:33:54,360 --> 00:33:56,680 Speaker 1: it landed directly behind me. And I thought I had 542 00:33:56,720 --> 00:34:00,600 Speaker 1: just been hit by a shotgun. Okay, turned I wasn't 543 00:34:01,120 --> 00:34:05,040 Speaker 1: well and and and at that time it wasn't uh 544 00:34:05,280 --> 00:34:09,240 Speaker 1: popular knowledge. I probably shouldn't say common knowledge, but popular knowledge. 545 00:34:09,239 --> 00:34:13,080 Speaker 1: People just didn't know, uh that there was mercury in there. Now, 546 00:34:13,120 --> 00:34:16,160 Speaker 1: I mean, admittedly there's not a boatload of mercury in there, 547 00:34:16,200 --> 00:34:19,480 Speaker 1: but you know, it could it could be something serious. 548 00:34:20,040 --> 00:34:23,279 Speaker 1: And that's why when you're fluorescent light spurned out, it's 549 00:34:23,360 --> 00:34:25,840 Speaker 1: a good idea to find someone who can take it 550 00:34:25,880 --> 00:34:29,239 Speaker 1: and recycle that, not only for safety reasons, but also 551 00:34:29,239 --> 00:34:31,919 Speaker 1: because you know they can recover some of that material. Now, 552 00:34:33,040 --> 00:34:37,040 Speaker 1: when you're talking about the fluorescent light tubes, uh, that's 553 00:34:37,040 --> 00:34:39,400 Speaker 1: pretty much it. I mean you've got the uh the 554 00:34:39,440 --> 00:34:41,400 Speaker 1: tube of gas with the caps on the end, and 555 00:34:41,440 --> 00:34:45,400 Speaker 1: you plug it into the uh the light fixture to 556 00:34:45,800 --> 00:34:49,680 Speaker 1: have it work. Well, there's there's other stuff underneath that 557 00:34:50,200 --> 00:34:52,239 Speaker 1: that you may not necessarily see. It's it's covered up 558 00:34:52,239 --> 00:34:55,719 Speaker 1: by the fixture. UM. One of the most important parts 559 00:34:55,719 --> 00:34:58,279 Speaker 1: I would argue is the ballast, which is a type 560 00:34:58,280 --> 00:35:03,799 Speaker 1: of transformer uh um that basically ups the electricity to 561 00:35:04,360 --> 00:35:07,359 Speaker 1: make it work better with the fluorescent light. Because again, 562 00:35:07,400 --> 00:35:10,120 Speaker 1: you have to introduce those ions, which is not necessarily 563 00:35:10,120 --> 00:35:12,839 Speaker 1: easy to do, especially since you've gotten inert gas in there. 564 00:35:13,360 --> 00:35:16,120 Speaker 1: So if you ever looked at a compact fluorescent light 565 00:35:16,280 --> 00:35:19,280 Speaker 1: or curly bulb as I like to call them, UM 566 00:35:19,280 --> 00:35:22,319 Speaker 1: because I like to do that UM and wonder what 567 00:35:22,400 --> 00:35:25,440 Speaker 1: the heck the big honking bases that you have to 568 00:35:25,480 --> 00:35:29,560 Speaker 1: screw into a regular light fixture. That's where the ballast is. 569 00:35:29,640 --> 00:35:33,800 Speaker 1: The ballast is built into the base of that uh 570 00:35:33,840 --> 00:35:37,759 Speaker 1: that fixture, UM, which is why it may or may 571 00:35:37,800 --> 00:35:40,719 Speaker 1: not fit into that incandescent and that that fixture that 572 00:35:40,760 --> 00:35:45,000 Speaker 1: you bought that would allow you to use a UM 573 00:35:45,040 --> 00:35:49,160 Speaker 1: a typical incandescent bulb. Now they say in some cases 574 00:35:49,160 --> 00:35:51,680 Speaker 1: that you should not use those because they do generate 575 00:35:51,760 --> 00:35:55,839 Speaker 1: heat and that can uh make the ballast overheat, uh 576 00:35:56,239 --> 00:35:59,839 Speaker 1: cause a short circuit and possibly fire. You know at 577 00:35:59,840 --> 00:36:01,279 Speaker 1: the ends on what kind of fixture you have, So 578 00:36:01,360 --> 00:36:03,360 Speaker 1: keep an eye on that. But if you've wondered what 579 00:36:03,480 --> 00:36:07,200 Speaker 1: that what that situation is, UM, it's built into the ballast. 580 00:36:07,280 --> 00:36:09,520 Speaker 1: And the ballast is also in that case what controls 581 00:36:09,560 --> 00:36:12,560 Speaker 1: the three way There are some three way fluorescent compact 582 00:36:12,560 --> 00:36:17,360 Speaker 1: fluorescent lights. UM. The ballast is what makes that possible 583 00:36:17,400 --> 00:36:22,480 Speaker 1: because it can control the amount of electricity going into 584 00:36:22,600 --> 00:36:25,279 Speaker 1: the tube. Yeah. It's also important to point out that 585 00:36:25,440 --> 00:36:30,640 Speaker 1: another big difference between using free electrons moving through a gas. 586 00:36:31,160 --> 00:36:35,560 Speaker 1: Essentially you're talking about ionized gas or plasma. But I 587 00:36:35,600 --> 00:36:38,320 Speaker 1: know if you're using free electrons moving through a gas, 588 00:36:38,360 --> 00:36:41,719 Speaker 1: it does behave differently than it would if those electrons 589 00:36:41,719 --> 00:36:45,160 Speaker 1: were moving through a wire. Uh. Now with a wire, 590 00:36:45,680 --> 00:36:48,920 Speaker 1: you know you have the resistance is dependent upon the 591 00:36:49,239 --> 00:36:53,440 Speaker 1: composition and the size of the wire in a in 592 00:36:53,560 --> 00:36:57,160 Speaker 1: gas discharge, which is in the terms of this not 593 00:36:57,400 --> 00:37:02,520 Speaker 1: something that's gross is uh uh, it's the resistance actually 594 00:37:03,360 --> 00:37:07,200 Speaker 1: decreases due to current. So when you've got a current going, 595 00:37:07,480 --> 00:37:10,640 Speaker 1: the resistance begins to decrease through this gas. That's more 596 00:37:10,640 --> 00:37:13,879 Speaker 1: electrons and ions start to flow through. They bump into 597 00:37:13,880 --> 00:37:17,640 Speaker 1: more atoms, frees up more electrons, creates more charged particles. 598 00:37:17,719 --> 00:37:22,600 Speaker 1: So the resistance is uh is constantly decreasing as long 599 00:37:22,640 --> 00:37:25,000 Speaker 1: as that currents on, and that can be a problem. 600 00:37:25,040 --> 00:37:29,080 Speaker 1: If that continues for too long, it'll blow out the 601 00:37:29,120 --> 00:37:33,560 Speaker 1: electrical components of the the the entire system. So that's 602 00:37:33,560 --> 00:37:36,520 Speaker 1: another reason why these ballasts are important. They are little 603 00:37:37,000 --> 00:37:42,120 Speaker 1: safety features that control that so that the current doesn't 604 00:37:42,200 --> 00:37:47,560 Speaker 1: continue indefinitely. It stops briefly, but not so briefly as 605 00:37:47,640 --> 00:37:51,560 Speaker 1: to make the lightbulb turn off, or at least if 606 00:37:51,560 --> 00:37:53,440 Speaker 1: it's turning off, it's turning off at a rate so 607 00:37:53,520 --> 00:37:57,120 Speaker 1: fast that we can't really detect it. Uh. You may 608 00:37:57,120 --> 00:38:00,440 Speaker 1: have noticed, you know, lightbulbs that for us and bulbs 609 00:38:00,480 --> 00:38:03,200 Speaker 1: that flicker like even when they're on, they're just they're 610 00:38:03,200 --> 00:38:06,879 Speaker 1: just flickering. And that's generally speaking, that's the ballast that 611 00:38:07,120 --> 00:38:10,840 Speaker 1: is trying to control this. And you're talking about alternating currents, 612 00:38:10,880 --> 00:38:13,880 Speaker 1: the currents running essentially one way and then another way, 613 00:38:14,239 --> 00:38:16,640 Speaker 1: so it's doing it, you know, and the ballast is 614 00:38:16,680 --> 00:38:21,400 Speaker 1: working for both directions of current and UH, and some 615 00:38:21,480 --> 00:38:26,520 Speaker 1: of the older bulbs, the system was not controlled very well, 616 00:38:26,520 --> 00:38:30,160 Speaker 1: like they might have used a magnetic ballast, which has 617 00:38:30,200 --> 00:38:33,480 Speaker 1: a slightly slower reaction time than current ballasts that are 618 00:38:34,600 --> 00:38:38,960 Speaker 1: UH that are usually based on circuitry. So those older ballasts, 619 00:38:38,960 --> 00:38:41,080 Speaker 1: you know, it meant that if you had a fluorescent 620 00:38:41,080 --> 00:38:43,959 Speaker 1: bulb turned on, it might give you that flickering look 621 00:38:44,000 --> 00:38:46,879 Speaker 1: and you might feel like your workplace is the same 622 00:38:46,920 --> 00:38:49,720 Speaker 1: one that was in the documentary Joe Versus the Volcano. 623 00:38:49,880 --> 00:38:54,200 Speaker 1: And that's right, you have a brain cloud. Well, then 624 00:38:54,239 --> 00:38:57,880 Speaker 1: you have to go to this volcano. Uh, and encounter 625 00:38:58,160 --> 00:39:03,319 Speaker 1: three different versions of the same triss And I was see, 626 00:39:03,560 --> 00:39:06,040 Speaker 1: I was working on a joke about how when you 627 00:39:06,080 --> 00:39:08,120 Speaker 1: were flying in your hot air balloon and you needed 628 00:39:08,160 --> 00:39:11,000 Speaker 1: to go higher, you would throughout the fluorescent light fixtures 629 00:39:11,040 --> 00:39:13,480 Speaker 1: because you know the kind of throw the ballast's overboard. 630 00:39:14,080 --> 00:39:17,640 Speaker 1: Ironically enough, that's somewhat true. I've changed a ballast out 631 00:39:17,680 --> 00:39:21,200 Speaker 1: of my fluorescent light fixture in my kitchen and they're heavy. 632 00:39:20,960 --> 00:39:23,920 Speaker 1: They it's like a brick. Anyway, Well, we should probably 633 00:39:23,920 --> 00:39:26,279 Speaker 1: move on to the third type of light bulb by 634 00:39:26,320 --> 00:39:29,319 Speaker 1: wanting to talk about the LED. Actually, if you look 635 00:39:29,400 --> 00:39:32,520 Speaker 1: at our article believe it or not, there's an article 636 00:39:32,520 --> 00:39:35,600 Speaker 1: on how stuff works dot com about light emitting diodes. Yeah, 637 00:39:35,640 --> 00:39:37,520 Speaker 1: we have articles on all of this, which made this 638 00:39:37,560 --> 00:39:42,160 Speaker 1: podcast way easy to research. Yes, yes, But the funny 639 00:39:42,160 --> 00:39:44,360 Speaker 1: thing is if you look at the diagram, the the 640 00:39:44,440 --> 00:39:47,040 Speaker 1: cross section that are artists have put together of a 641 00:39:47,160 --> 00:39:49,680 Speaker 1: light emitting diode, it's sort of in a way resembles 642 00:39:50,280 --> 00:39:54,080 Speaker 1: an incandescent light bulb because it is a diode inside 643 00:39:54,080 --> 00:39:57,680 Speaker 1: a casing. Yeah. Now, in this case, the the light 644 00:39:57,760 --> 00:40:01,160 Speaker 1: of right, the light emitting die, it is a type 645 00:40:01,160 --> 00:40:05,400 Speaker 1: of semiconductor. Actually, in a way, it's the simplest semiconductor. 646 00:40:05,440 --> 00:40:07,960 Speaker 1: There is a diode in general, not just a light 647 00:40:08,000 --> 00:40:10,440 Speaker 1: emitting diode, but a diode in general is a semiconductor, 648 00:40:10,840 --> 00:40:16,280 Speaker 1: and it conducts electricity, but not as completely as it could. Right. Essentially, 649 00:40:16,320 --> 00:40:20,239 Speaker 1: it's a semiconductor has a varying ability to conduct electricity, 650 00:40:20,280 --> 00:40:23,800 Speaker 1: so sometimes it connect like an insulator, sometimes as a conductor. 651 00:40:23,920 --> 00:40:27,200 Speaker 1: It all depends on this stuff. Generally speaking, if you 652 00:40:27,320 --> 00:40:31,640 Speaker 1: control what what you have is, you've got a semiconductor 653 00:40:31,719 --> 00:40:34,759 Speaker 1: with two different types of material and it tends we 654 00:40:34,760 --> 00:40:37,840 Speaker 1: tend to call it N type material and P type material. 655 00:40:38,360 --> 00:40:43,400 Speaker 1: So the N type material has extra negatively charged particles, 656 00:40:44,000 --> 00:40:48,200 Speaker 1: so it has a negative charge overall. Then the P 657 00:40:48,440 --> 00:40:50,640 Speaker 1: type material, I think you can see where this is going, 658 00:40:51,040 --> 00:40:57,040 Speaker 1: has extra positively charged particles. Yes I'm positive, not just sure, 659 00:40:57,719 --> 00:41:02,120 Speaker 1: I'm positive. So you can think of the N type 660 00:41:02,120 --> 00:41:05,799 Speaker 1: material as having an excess of electrons. The P type 661 00:41:05,800 --> 00:41:09,479 Speaker 1: material has what we call holes. These are places where 662 00:41:09,480 --> 00:41:13,479 Speaker 1: the electrons could go. Now, electrons definitely want to get 663 00:41:13,520 --> 00:41:16,960 Speaker 1: over to the positively charged holes. They want to move 664 00:41:17,000 --> 00:41:20,080 Speaker 1: to those holes because, as we know, when you're talking 665 00:41:20,080 --> 00:41:26,560 Speaker 1: about charges, opposites tracked John Marcia. Yes, in in subatomic 666 00:41:26,640 --> 00:41:30,040 Speaker 1: particle form. So you've got the negative and the positive 667 00:41:30,840 --> 00:41:33,719 Speaker 1: materials and they're kind of smushed together in a in 668 00:41:33,760 --> 00:41:37,040 Speaker 1: a diode. So you've you bond together the N type 669 00:41:37,040 --> 00:41:40,439 Speaker 1: material to the P type material. So you've got the 670 00:41:40,440 --> 00:41:43,920 Speaker 1: the negatively charged and the positively charged botted together. And 671 00:41:43,960 --> 00:41:47,319 Speaker 1: there's an electrode attached to each end. So the N 672 00:41:47,360 --> 00:41:49,279 Speaker 1: type has an electrode attached, the P type has an 673 00:41:49,280 --> 00:41:54,480 Speaker 1: electrode attached. Now, if you don't apply any voltage across 674 00:41:54,520 --> 00:41:57,879 Speaker 1: this diode, the electrons from the N type material fill 675 00:41:58,000 --> 00:42:00,839 Speaker 1: up the holes in the P type material, and it 676 00:42:01,080 --> 00:42:04,880 Speaker 1: creates what is called a depletion zone. And in the 677 00:42:04,920 --> 00:42:09,759 Speaker 1: depletion zone, the semiconductor becomes an insulator. You know, you've 678 00:42:09,800 --> 00:42:12,800 Speaker 1: you've got those extra electrons, have filled up the holes 679 00:42:13,120 --> 00:42:16,200 Speaker 1: that were on the positively charge side, and you've reached 680 00:42:16,239 --> 00:42:20,319 Speaker 1: sort of a neutral ground, right, So depletion zone is 681 00:42:20,400 --> 00:42:24,840 Speaker 1: that neutral ground. There are no free electrons or empty spaces, 682 00:42:24,920 --> 00:42:28,279 Speaker 1: so it's just kind of there. But if you want 683 00:42:28,280 --> 00:42:30,799 Speaker 1: to get rid of that depletion zone, then you need 684 00:42:30,840 --> 00:42:35,160 Speaker 1: to push electrons across, moving from the N type area 685 00:42:35,480 --> 00:42:39,480 Speaker 1: towards the P type area. And then to do that, 686 00:42:39,520 --> 00:42:42,560 Speaker 1: you just connect the the IN type side of the 687 00:42:42,600 --> 00:42:45,239 Speaker 1: diode to the negative end of a circuit P type 688 00:42:45,280 --> 00:42:47,960 Speaker 1: side to the positive end, and the free electrons and 689 00:42:47,960 --> 00:42:50,359 Speaker 1: the N type material are repelled by the negative side 690 00:42:50,360 --> 00:42:53,799 Speaker 1: because again you know like charge repels like yes, they're 691 00:42:53,880 --> 00:42:57,440 Speaker 1: drawn to the positive end, and you then complete the 692 00:42:57,880 --> 00:43:01,840 Speaker 1: circuit and you get this um you get this electron movement. 693 00:43:02,200 --> 00:43:04,000 Speaker 1: If you try to go the other way, it wouldn't 694 00:43:04,000 --> 00:43:08,280 Speaker 1: work because the negatively charged particles going into the positive 695 00:43:08,320 --> 00:43:09,880 Speaker 1: end would just fill up the holes and then it 696 00:43:09,920 --> 00:43:13,440 Speaker 1: would stop. So a diode is kind of like a 697 00:43:13,480 --> 00:43:16,920 Speaker 1: one way street and electronics. If you hook up a diode, 698 00:43:17,480 --> 00:43:20,480 Speaker 1: uh current can only flow in one direction and it 699 00:43:20,520 --> 00:43:22,359 Speaker 1: will not flow the other way. So if you even 700 00:43:22,400 --> 00:43:26,520 Speaker 1: if you reversed the current, it would not complete the 701 00:43:26,560 --> 00:43:31,319 Speaker 1: circuit if it went against the diode, Reversing the polarity 702 00:43:31,480 --> 00:43:39,400 Speaker 1: just won't work, captain. So so that's your basic led. 703 00:43:39,680 --> 00:43:43,919 Speaker 1: But visible light emitting diode are made up of materials 704 00:43:43,960 --> 00:43:48,280 Speaker 1: that create a a wide gap between where the hole 705 00:43:48,400 --> 00:43:50,680 Speaker 1: is and where the electrons are, so that when the 706 00:43:50,680 --> 00:43:53,920 Speaker 1: electrons move through they do emit, They give off photons 707 00:43:54,040 --> 00:43:56,600 Speaker 1: because again we're talking about when electrons are moving down 708 00:43:56,640 --> 00:43:59,640 Speaker 1: through the orbitals. Uh, you know, you you've given them 709 00:43:59,719 --> 00:44:02,080 Speaker 1: enough energy for them to to move out of their 710 00:44:02,080 --> 00:44:05,680 Speaker 1: normal orbitals. Once they move down, they give off light. Well, 711 00:44:05,719 --> 00:44:09,120 Speaker 1: the greater that gap is, the more light they give off. 712 00:44:09,840 --> 00:44:14,839 Speaker 1: So if you create a visible light emitting diode and 713 00:44:14,960 --> 00:44:18,280 Speaker 1: you use these materials that create these wider gaps between 714 00:44:18,280 --> 00:44:22,959 Speaker 1: the conduction band and the lower orbitals of the electrons, 715 00:44:23,560 --> 00:44:27,000 Speaker 1: that gap is what allows the electrons to give off light. 716 00:44:27,560 --> 00:44:29,719 Speaker 1: And in general, these l e d s tend to 717 00:44:29,760 --> 00:44:32,160 Speaker 1: look if you look at a single LED, they tend 718 00:44:32,200 --> 00:44:34,600 Speaker 1: to look like a miniature light bulb light Christmas saying, 719 00:44:35,400 --> 00:44:38,080 Speaker 1: now there's no filament in there, because again you're just 720 00:44:38,320 --> 00:44:41,239 Speaker 1: what all you're doing is you're allowing those electrons to 721 00:44:41,640 --> 00:44:45,919 Speaker 1: move in those those um orbitals and that's what's giving 722 00:44:45,920 --> 00:44:48,120 Speaker 1: off the photons. And these little light bulbs tend to 723 00:44:48,160 --> 00:44:51,040 Speaker 1: be shaped in such a way that it guides the 724 00:44:51,160 --> 00:44:54,279 Speaker 1: light that's emitted in a very particular direction, so that 725 00:44:54,320 --> 00:44:57,239 Speaker 1: way it's a very concentrated light. So if you see 726 00:44:57,440 --> 00:45:00,560 Speaker 1: an LED light fixture, and this could be you know, 727 00:45:00,800 --> 00:45:04,239 Speaker 1: an LED light bulb or on on the back of cars. 728 00:45:04,239 --> 00:45:07,520 Speaker 1: I've seen a lot of um uh tail lights in 729 00:45:07,600 --> 00:45:10,200 Speaker 1: recent cars that use L E D s And you 730 00:45:10,239 --> 00:45:14,040 Speaker 1: can tell because it will be a group of them together. Um. 731 00:45:14,080 --> 00:45:15,760 Speaker 1: And so it looks like there are lots of little 732 00:45:15,760 --> 00:45:18,160 Speaker 1: tiny dots of light in a pattern you know, maybe 733 00:45:18,200 --> 00:45:23,400 Speaker 1: a um a series of concentric circle type things, or 734 00:45:23,520 --> 00:45:26,160 Speaker 1: or you know some other kind of thing um, and 735 00:45:26,239 --> 00:45:28,000 Speaker 1: it's you can you can tell that it's an LED 736 00:45:28,120 --> 00:45:31,360 Speaker 1: light specifically because you can see the little dots. But together, 737 00:45:31,400 --> 00:45:34,280 Speaker 1: when they work together like that, they can be very bright. 738 00:45:34,400 --> 00:45:36,319 Speaker 1: I have a couple of LED flashlights as a matter 739 00:45:36,320 --> 00:45:39,560 Speaker 1: of fact, um that you know. You it's like, hey, 740 00:45:39,600 --> 00:45:43,879 Speaker 1: does this thing work? Oh you know? Um. However, they're 741 00:45:44,000 --> 00:45:46,359 Speaker 1: very efficient. Yes, yes, I've got a couple of LED 742 00:45:46,600 --> 00:45:48,759 Speaker 1: lights in my house. Actually, there are a couple of 743 00:45:48,800 --> 00:45:51,279 Speaker 1: light fixtures that were specifically designed to work with L 744 00:45:51,280 --> 00:45:55,480 Speaker 1: A D lights and um, yes, they are incredibly efficient, 745 00:45:55,920 --> 00:45:59,439 Speaker 1: particularly compared to incandescence and even fluorescence. But we didn't 746 00:45:59,480 --> 00:46:02,480 Speaker 1: really mention, but florescent lights are more efficient than incandescent 747 00:46:02,560 --> 00:46:05,880 Speaker 1: light bulbs, They last longer, they use less energy to 748 00:46:05,960 --> 00:46:08,680 Speaker 1: create light. They don't they don't lose as much energy 749 00:46:08,840 --> 00:46:13,919 Speaker 1: in producing heat. So yeah, so they don't heat up 750 00:46:13,960 --> 00:46:16,440 Speaker 1: as hot as an incandescent bulb. That's not saying that 751 00:46:16,480 --> 00:46:18,760 Speaker 1: a fluorescent bulb is going to be cool to the touch, 752 00:46:19,600 --> 00:46:21,279 Speaker 1: it's just not going to be as hot as an 753 00:46:21,320 --> 00:46:25,520 Speaker 1: incandescent bulb. Is l e ED is even more efficient. Uh, 754 00:46:25,800 --> 00:46:30,000 Speaker 1: it has a much higher luminous efficacy, if you will. 755 00:46:30,440 --> 00:46:33,160 Speaker 1: As we say in our article on l E D sage. 756 00:46:33,200 --> 00:46:36,680 Speaker 1: I'm sorry, um, but they talked about how in our 757 00:46:36,800 --> 00:46:40,600 Speaker 1: article they mentioned a specific type of LED light bulb. 758 00:46:40,640 --> 00:46:44,200 Speaker 1: In this case, it was the Sewel's Evo lux LED bulb, 759 00:46:44,760 --> 00:46:48,600 Speaker 1: which produces seventy six point nine lumens per what, which 760 00:46:48,600 --> 00:46:52,040 Speaker 1: is essentially how bright This is dependent upon how much 761 00:46:52,120 --> 00:46:55,279 Speaker 1: energy you're putting into it. Whereas an incandescent bulb is 762 00:46:55,520 --> 00:47:00,800 Speaker 1: seventeen lumens per what, So seventy six point nine for seventeen. 763 00:47:01,280 --> 00:47:04,120 Speaker 1: It shows that the efficiency of the l e ED 764 00:47:04,360 --> 00:47:07,160 Speaker 1: is far greater than that of the incandescent bulb. And 765 00:47:07,880 --> 00:47:13,760 Speaker 1: the LED lifetime can be around fifty thousand hours, So 766 00:47:14,000 --> 00:47:18,040 Speaker 1: compare that to a couple of thousand hours for a 767 00:47:18,200 --> 00:47:22,879 Speaker 1: typical incandescent bulb, and that's a big difference. Now, LED 768 00:47:23,000 --> 00:47:26,520 Speaker 1: light bulbs do tend to be much more expensive than 769 00:47:26,600 --> 00:47:30,720 Speaker 1: incandescent or fluorescent bulbs. However, if you measure that across 770 00:47:30,840 --> 00:47:33,560 Speaker 1: the lifetime of the bulb and you factor in things 771 00:47:33,600 --> 00:47:37,879 Speaker 1: like energy savings, uh, they on the long term can 772 00:47:37,920 --> 00:47:41,359 Speaker 1: be a good investment. However, the upfront cost is still 773 00:47:41,520 --> 00:47:43,840 Speaker 1: much higher, so that can be a barrier for a 774 00:47:43,840 --> 00:47:47,719 Speaker 1: lot of people. The cost has been decreasing uh quite 775 00:47:47,719 --> 00:47:51,439 Speaker 1: a bit since over the last decade or so, since 776 00:47:51,480 --> 00:47:56,560 Speaker 1: semiconductor material has become much more cost effective. Is when 777 00:47:56,719 --> 00:48:01,160 Speaker 1: these first came out, semiconductor material was a precious commodity. 778 00:48:01,200 --> 00:48:03,160 Speaker 1: It was not something that was mass produced. It was 779 00:48:03,200 --> 00:48:05,200 Speaker 1: not something that you could easily get your hands on, 780 00:48:05,239 --> 00:48:08,000 Speaker 1: and so it was much more expensive. But just as 781 00:48:08,000 --> 00:48:12,879 Speaker 1: Gordon More predicted way back in the sixties, the manufacturing 782 00:48:12,880 --> 00:48:16,719 Speaker 1: processes would mean that costs would come down, efficiencies go up, 783 00:48:16,760 --> 00:48:19,560 Speaker 1: and as a result, we're able to get more efficient products. 784 00:48:19,600 --> 00:48:22,399 Speaker 1: Now he was talking specifically about integrated circuits, but as 785 00:48:22,400 --> 00:48:25,280 Speaker 1: it turns out, that kind of applies to lots of stuff. 786 00:48:26,560 --> 00:48:28,600 Speaker 1: Doesn't necessarily mean that the light bulbs will have next 787 00:48:28,680 --> 00:48:30,239 Speaker 1: year will be twice as bright as the ones we 788 00:48:30,239 --> 00:48:33,920 Speaker 1: have this year. So the analogy doesn't continue all the 789 00:48:33,960 --> 00:48:38,600 Speaker 1: way there, but it's still I think semi applicable. Uh. 790 00:48:38,680 --> 00:48:45,279 Speaker 1: So yeah, you can see the differences between these these approaches. Uh. Ultimately, 791 00:48:45,440 --> 00:48:49,080 Speaker 1: it's all about again exciting atoms, and once those aboms 792 00:48:49,120 --> 00:48:52,040 Speaker 1: get excited, they just light up, just like Chris does 793 00:48:52,480 --> 00:48:58,080 Speaker 1: whenever I talk about Inner Space, his favorite movie. His 794 00:48:58,160 --> 00:49:00,839 Speaker 1: face is lighting up right now. People, if you could 795 00:49:00,840 --> 00:49:03,479 Speaker 1: call it that, Yeah, it's uh, it's funny. They're they're 796 00:49:03,520 --> 00:49:06,560 Speaker 1: so excited and they just can't hide it. That's true. 797 00:49:07,000 --> 00:49:09,560 Speaker 1: They're about to lose control. They think they like it, 798 00:49:09,680 --> 00:49:13,560 Speaker 1: they think alright, So that wraps up I think this discussion. 799 00:49:13,640 --> 00:49:15,239 Speaker 1: Unless you have anything else you want to add to 800 00:49:15,360 --> 00:49:17,839 Speaker 1: light bulbs, Nope, all right, let's sign off. You guys 801 00:49:17,840 --> 00:49:21,560 Speaker 1: can switch off the lights now. We're gonna wrap this up. 802 00:49:21,600 --> 00:49:24,359 Speaker 1: You guys. If you have any topics you would like 803 00:49:24,480 --> 00:49:27,800 Speaker 1: us to tackle in future episodes of tech Stuff, shoot 804 00:49:27,880 --> 00:49:31,480 Speaker 1: us an email that addresses tech Stuff at Discovery dot com, 805 00:49:31,760 --> 00:49:33,839 Speaker 1: or let us know on Facebook or Twitter. You can 806 00:49:33,840 --> 00:49:37,480 Speaker 1: find us there with the handle text stuff hs W 807 00:49:37,719 --> 00:49:40,359 Speaker 1: and Chris and I will thought you again really soon. 808 00:49:42,640 --> 00:49:45,080 Speaker 1: For more on this and thousands of other topics. Is 809 00:49:45,080 --> 00:49:46,359 Speaker 1: it how stuff works. Dot com