1 00:00:08,520 --> 00:00:12,560 Speaker 1: Hey, Daniel, do you have solar power panels on your roof? Embarrassingly, 2 00:00:12,760 --> 00:00:15,680 Speaker 1: I don't. You don't? Why not? I just haven't gotten 3 00:00:15,720 --> 00:00:17,919 Speaker 1: around to it yet. It's the honest roof, so there's 4 00:00:17,960 --> 00:00:20,880 Speaker 1: kind of an energy barrier there. I know, I know 5 00:00:21,000 --> 00:00:23,320 Speaker 1: I should do it, but you know, prices keep falling, 6 00:00:23,360 --> 00:00:25,200 Speaker 1: and I guess that's what I say to myself to 7 00:00:25,320 --> 00:00:29,160 Speaker 1: justify my laziness. Oh man, you just cheap. We would 8 00:00:29,160 --> 00:00:32,120 Speaker 1: you get solar panels if they caused pennies or if 9 00:00:32,159 --> 00:00:36,000 Speaker 1: they could repair themselves and automatically reproduce. Well, that's an 10 00:00:36,000 --> 00:00:54,319 Speaker 1: offer so powerful I could hardly refuse. I am more 11 00:00:54,360 --> 00:00:58,200 Speaker 1: handmade cartoonists and the creator of PhD comics. I'm Daniel. 12 00:00:58,360 --> 00:01:01,480 Speaker 1: I'm a particle physicist, and like you, I haven't to 13 00:01:01,640 --> 00:01:04,559 Speaker 1: do list that's too long. Welcome to our podcast, Daniel 14 00:01:04,600 --> 00:01:07,800 Speaker 1: and Jorge Explain the Universe, a production of I Heart Radio, 15 00:01:07,959 --> 00:01:09,960 Speaker 1: in which we talk about all the things that are 16 00:01:10,000 --> 00:01:13,040 Speaker 1: amazing about the universe, all the places our curiosity has 17 00:01:13,080 --> 00:01:15,399 Speaker 1: taken us, all the questions we have asked and all 18 00:01:15,440 --> 00:01:18,520 Speaker 1: the answers we have found so far. But we love 19 00:01:18,560 --> 00:01:20,240 Speaker 1: to talk about the questions that we have in the 20 00:01:20,360 --> 00:01:23,280 Speaker 1: questions that you have, the things that you are curious 21 00:01:23,319 --> 00:01:25,240 Speaker 1: about the universe. Yeah, we like to take you to 22 00:01:25,240 --> 00:01:28,280 Speaker 1: the far reaches of the cosmos, to other galaxies and 23 00:01:28,319 --> 00:01:30,920 Speaker 1: inside of black holes, but we also like to take 24 00:01:31,000 --> 00:01:34,160 Speaker 1: you to your neighborhood, to the world around you and 25 00:01:34,200 --> 00:01:37,319 Speaker 1: talk about the things and the questions that we have 26 00:01:37,840 --> 00:01:41,240 Speaker 1: in our everyday lives, because physics is everywhere. It's not 27 00:01:41,319 --> 00:01:43,600 Speaker 1: just out there in the center of black holes and 28 00:01:43,680 --> 00:01:46,880 Speaker 1: the craziness of neutron stars. It is right here making 29 00:01:46,920 --> 00:01:51,040 Speaker 1: our lives better. Or maybe, Jorge, you'd say this is engineering. Yes, yes, 30 00:01:51,080 --> 00:01:55,240 Speaker 1: I would say that. Or maybe finally, this is physics 31 00:01:55,240 --> 00:01:59,280 Speaker 1: and engineering working harmoniously together. Yeah, because as humans, we've 32 00:01:59,280 --> 00:02:02,160 Speaker 1: made a lot of knowledgy and a lot of progress 33 00:02:02,160 --> 00:02:04,080 Speaker 1: in science and knowing how things work to the point 34 00:02:04,080 --> 00:02:07,280 Speaker 1: where we can create things that take advantage of nature 35 00:02:07,320 --> 00:02:10,280 Speaker 1: to make our lives easier. That's right, Because the universe 36 00:02:10,360 --> 00:02:14,079 Speaker 1: is out there pumping out energy into space, these crazy 37 00:02:14,160 --> 00:02:17,760 Speaker 1: nuclear bombs going off at the center of every solar system, 38 00:02:17,840 --> 00:02:20,880 Speaker 1: and so of course it's tempting to potentially take advantage 39 00:02:20,880 --> 00:02:22,560 Speaker 1: of that. Yeah, So today we will be tackling a 40 00:02:22,639 --> 00:02:25,240 Speaker 1: question that a lot of readers have sent in, right, Daniel, 41 00:02:25,600 --> 00:02:27,960 Speaker 1: that's right. A lot of folks see these things on 42 00:02:28,040 --> 00:02:30,440 Speaker 1: the roofs in their neighborhoods and they wonder how does 43 00:02:30,480 --> 00:02:32,840 Speaker 1: that work? What's going on in there? So to be 44 00:02:32,919 --> 00:02:39,840 Speaker 1: on the program, we'll be asking the question how do 45 00:02:39,960 --> 00:02:43,000 Speaker 1: solar panels work. It's a really fun question because you 46 00:02:43,080 --> 00:02:45,520 Speaker 1: see these on the roofs in your neighborhood, and you 47 00:02:45,600 --> 00:02:49,200 Speaker 1: know they generate electricity, but how does it actually happen. 48 00:02:49,400 --> 00:02:51,880 Speaker 1: I mean, we know the sun pumps out energy, but 49 00:02:51,919 --> 00:02:55,520 Speaker 1: how does that turn into zippy electrons in your iPhone battery. 50 00:02:55,800 --> 00:02:59,200 Speaker 1: I have solar panels in my roof. It's amazing. I 51 00:02:59,200 --> 00:03:02,480 Speaker 1: haven't paid any electricity bill in like years. In fact, 52 00:03:02,600 --> 00:03:06,079 Speaker 1: the electric company writes me checks for how much energy produce. 53 00:03:06,160 --> 00:03:08,560 Speaker 1: So you are the electric company now I am my 54 00:03:08,600 --> 00:03:13,240 Speaker 1: own company. Yes, yeah, I know. It's pretty awesome. I 55 00:03:13,240 --> 00:03:15,359 Speaker 1: mean you invest in it and then it pays off 56 00:03:15,440 --> 00:03:17,120 Speaker 1: over the years. Yeah. And it makes a lot of 57 00:03:17,120 --> 00:03:19,480 Speaker 1: sense because in the end, the sun is the direct 58 00:03:19,480 --> 00:03:22,400 Speaker 1: source of almost all the energy we use here on Earth. 59 00:03:22,680 --> 00:03:26,560 Speaker 1: Even fossil fuels originally just came from energy from the sun, 60 00:03:26,880 --> 00:03:29,120 Speaker 1: and so it's tempting to say, hey, let's just go 61 00:03:29,280 --> 00:03:32,240 Speaker 1: direct to the source. Why build a fusion reactor here 62 00:03:32,280 --> 00:03:33,920 Speaker 1: on Earth when we have a huge one in the 63 00:03:33,960 --> 00:03:36,520 Speaker 1: center of our solar system, Let's just suck up some 64 00:03:36,600 --> 00:03:38,680 Speaker 1: of that energy. Yeah, because it sort of feels like 65 00:03:38,680 --> 00:03:41,680 Speaker 1: a waste almost, you know, Like I think about all 66 00:03:41,680 --> 00:03:43,960 Speaker 1: of the energy that used to hit my roof before 67 00:03:43,960 --> 00:03:46,880 Speaker 1: I had a solar panels, and all the energy just 68 00:03:46,960 --> 00:03:49,200 Speaker 1: kind of goes to waste. It just hits the roof 69 00:03:49,280 --> 00:03:51,080 Speaker 1: and bounces and heats it up a little bit, but 70 00:03:51,080 --> 00:03:53,600 Speaker 1: then it cools down again at night. So I feel 71 00:03:53,640 --> 00:03:56,640 Speaker 1: so much more like I'm taking advantage of nature in 72 00:03:57,080 --> 00:03:59,080 Speaker 1: using up the energy that's there. Right, So you're not 73 00:03:59,120 --> 00:04:00,880 Speaker 1: just doing it for the econom benefits, You're doing it 74 00:04:00,880 --> 00:04:04,680 Speaker 1: because it makes you feel like a better person. Honestly. Yeah, 75 00:04:04,880 --> 00:04:08,160 Speaker 1: I feel like I invested in a more guilt free lifestyle. 76 00:04:08,560 --> 00:04:10,400 Speaker 1: Like in the summer, we can just turn on the 77 00:04:10,440 --> 00:04:13,120 Speaker 1: A C guilt free because it's all coming from the 78 00:04:13,160 --> 00:04:15,440 Speaker 1: sun and have a second box of cookies. Right. Yeah, 79 00:04:15,520 --> 00:04:17,920 Speaker 1: And you're right, there is a huge amount of energy there. 80 00:04:18,160 --> 00:04:20,800 Speaker 1: The amount of sunlight that falls on the Earth is 81 00:04:20,839 --> 00:04:26,000 Speaker 1: like a hundred and seventy three thousand terra wats. It's incredible. 82 00:04:26,080 --> 00:04:28,640 Speaker 1: It's a lot of wats. That's a lot of terra wats. 83 00:04:29,120 --> 00:04:31,359 Speaker 1: And it's actually a thousand times more than the entire 84 00:04:31,440 --> 00:04:36,640 Speaker 1: energy budget of our civilization. Wow, meaning that a thousand 85 00:04:36,640 --> 00:04:39,680 Speaker 1: times more energy falls on Earth from the Sun than 86 00:04:39,720 --> 00:04:42,760 Speaker 1: we use. Yeah, so if you could capture the solar energy, 87 00:04:42,800 --> 00:04:46,600 Speaker 1: you could easily power the entire civilization with just a 88 00:04:46,720 --> 00:04:49,360 Speaker 1: fraction of the energy that comes from the Sun. So 89 00:04:49,680 --> 00:04:53,239 Speaker 1: it's a huge resource. It's incredibly powerful. It's right there. 90 00:04:53,400 --> 00:04:55,920 Speaker 1: It seems awfully tempting to try to capture it. What 91 00:04:56,000 --> 00:04:57,800 Speaker 1: would be the number, Daniel is, So if it's a 92 00:04:57,839 --> 00:05:00,200 Speaker 1: thousand times more, does that mean that if we over 93 00:05:00,320 --> 00:05:04,440 Speaker 1: the earth the Earth in solar panels, we would be 94 00:05:04,560 --> 00:05:07,520 Speaker 1: set if it was efficient. Yeah. I've seen lots of 95 00:05:07,520 --> 00:05:11,080 Speaker 1: different calculations actually about how many solar panels you would need, 96 00:05:11,320 --> 00:05:13,720 Speaker 1: But you don't need to cover a significant fraction of 97 00:05:13,800 --> 00:05:16,520 Speaker 1: the Earth and solar panels to get enough energy to 98 00:05:16,800 --> 00:05:18,960 Speaker 1: power the Earth. We'll talk about a little bit more later. 99 00:05:19,200 --> 00:05:21,839 Speaker 1: One of the biggest challenges actually is getting that power 100 00:05:21,880 --> 00:05:24,200 Speaker 1: to the right place and storing it and having it 101 00:05:24,279 --> 00:05:27,640 Speaker 1: at the right time. But it's a big percentage these days, 102 00:05:27,960 --> 00:05:30,599 Speaker 1: or a significant percentage of the power that we consume 103 00:05:30,680 --> 00:05:32,960 Speaker 1: these days, right, I mean, it's not like zero. It's 104 00:05:32,960 --> 00:05:35,080 Speaker 1: not like zero. Here in the US we get about 105 00:05:35,120 --> 00:05:38,760 Speaker 1: three percent of the energy that we use from solar panels, 106 00:05:38,800 --> 00:05:42,240 Speaker 1: but in other countries it's higher. China's four percent, Germany 107 00:05:42,320 --> 00:05:46,480 Speaker 1: is eight percent, Australia goes to nine percent, and Honduras 108 00:05:46,560 --> 00:05:50,800 Speaker 1: tops it out at well A sairly as understandable. I mean, 109 00:05:50,839 --> 00:05:54,960 Speaker 1: everything is bigger in Australia and Sunnier, even their solar panels. 110 00:05:55,760 --> 00:05:59,039 Speaker 1: Spiders and solar panels. Yeah, it aren't like the kangaroos 111 00:05:59,040 --> 00:06:00,840 Speaker 1: hanging out on top of the solar panels blocking it. 112 00:06:00,839 --> 00:06:03,880 Speaker 1: I wonder if that gets factored in. And I guess 113 00:06:03,880 --> 00:06:06,520 Speaker 1: the great thing about it is that it's carbon free, 114 00:06:06,640 --> 00:06:09,040 Speaker 1: Like it doesn't give off any emissions? Does it have 115 00:06:09,240 --> 00:06:12,240 Speaker 1: operating the solar panels certainly doesn't. There's a question of 116 00:06:12,279 --> 00:06:16,680 Speaker 1: constructing solar panels and infrastructure to store that and create batteries, 117 00:06:16,920 --> 00:06:19,920 Speaker 1: and there's definitely some toxic materials that are used and 118 00:06:19,960 --> 00:06:23,200 Speaker 1: created there. But operating solar panels no, they have no 119 00:06:23,320 --> 00:06:27,120 Speaker 1: moving parts. They just sit there and turn photons into electricity. 120 00:06:27,400 --> 00:06:30,440 Speaker 1: So they're pretty awesome. Yeah, so a big question that 121 00:06:30,560 --> 00:06:32,920 Speaker 1: our readers have is how do they work, Like, how 122 00:06:32,960 --> 00:06:37,880 Speaker 1: do they convert solar energy sunlight into electricity you can 123 00:06:37,960 --> 00:06:42,240 Speaker 1: use for your devices and video games and televisions and Netflix, 124 00:06:42,520 --> 00:06:44,320 Speaker 1: and so we were wondering how many people out there 125 00:06:44,440 --> 00:06:47,159 Speaker 1: know how solar panels work? That's right, and so I 126 00:06:47,200 --> 00:06:51,039 Speaker 1: asked folks who volunteered to speculate without googling about how 127 00:06:51,120 --> 00:06:54,239 Speaker 1: solar panels work. And if you'd like to speculate without 128 00:06:54,279 --> 00:06:58,159 Speaker 1: reference materials on difficult questions in physics, please write to 129 00:06:58,200 --> 00:07:01,520 Speaker 1: me at questions at Daniel and Jorge dot com. Yeah, 130 00:07:01,560 --> 00:07:03,120 Speaker 1: so think about it for a second. Do you know 131 00:07:03,160 --> 00:07:05,840 Speaker 1: how solar panels work? Here's what people had to say. 132 00:07:06,240 --> 00:07:09,039 Speaker 1: You know, I've never thought about it, um and I 133 00:07:09,120 --> 00:07:13,920 Speaker 1: have no idea. The panels capture the photons from the 134 00:07:13,960 --> 00:07:17,800 Speaker 1: sun and stored. You know, it's a circle of life, 135 00:07:18,240 --> 00:07:20,360 Speaker 1: you know. I don't really know the specifics. I know 136 00:07:21,440 --> 00:07:25,160 Speaker 1: that they're also called like photo voltaic panels. I don't 137 00:07:25,160 --> 00:07:26,920 Speaker 1: know if I'm saying that right. I've only ever seen 138 00:07:26,960 --> 00:07:29,640 Speaker 1: the word written out, but which makes me think it's 139 00:07:29,680 --> 00:07:32,240 Speaker 1: got to have something to do with the photon specifically 140 00:07:32,320 --> 00:07:35,520 Speaker 1: interacting with the panel, you know, because I just saw 141 00:07:35,920 --> 00:07:41,520 Speaker 1: a small presentation last week. So sunlight activates the panels 142 00:07:41,680 --> 00:07:46,880 Speaker 1: the silly compounds, uh, and the cells produce electrical current, 143 00:07:47,200 --> 00:07:53,640 Speaker 1: which is converted in um electrical energy or no electrical 144 00:07:54,040 --> 00:07:58,160 Speaker 1: energy is converted in electrical power. My understanding is that 145 00:07:59,640 --> 00:08:06,800 Speaker 1: these solar energy hits these panels, and based on that energy, 146 00:08:07,000 --> 00:08:13,280 Speaker 1: there's some photo voltaic cells which translate that into electrical energy. 147 00:08:13,440 --> 00:08:17,000 Speaker 1: I'm not really sure how. Maybe because of the expanding heat, 148 00:08:17,320 --> 00:08:21,720 Speaker 1: it creates a differential and different metals. I know they 149 00:08:21,760 --> 00:08:25,240 Speaker 1: have photo voltaic cells in them, um, but I couldn't 150 00:08:25,240 --> 00:08:28,120 Speaker 1: explain the science behind it. All Right, A lot of 151 00:08:28,120 --> 00:08:30,080 Speaker 1: people seem to have some idea. A lot of people 152 00:08:30,080 --> 00:08:34,360 Speaker 1: said the words photo voltaic. That's pretty impressive. Yeah, that's 153 00:08:34,360 --> 00:08:36,160 Speaker 1: pretty awesome, and it goes to the core of the 154 00:08:36,160 --> 00:08:39,280 Speaker 1: physics that's happening inside solar panels. And I think often 155 00:08:39,320 --> 00:08:42,760 Speaker 1: they're called photo voltaic cells, and so that gives people 156 00:08:42,760 --> 00:08:45,920 Speaker 1: a clue about what's going on inside photo I guess 157 00:08:46,040 --> 00:08:49,360 Speaker 1: light will take just kind of a meaning electricity. Yeah, 158 00:08:49,440 --> 00:08:52,040 Speaker 1: and it is in the end of interaction between photons 159 00:08:52,080 --> 00:08:54,840 Speaker 1: and electrons, So it makes a lot of sense. All right, 160 00:08:54,880 --> 00:08:57,480 Speaker 1: Well let's break it down for folks. How do solar 161 00:08:57,520 --> 00:09:00,680 Speaker 1: panels work, Daniel? I mean, I assume they at sunlight 162 00:09:00,720 --> 00:09:05,760 Speaker 1: and somehow that gets transformed into electricity. So what's going on? Yeah, 163 00:09:05,800 --> 00:09:08,560 Speaker 1: So there's sort of two steps there. One is how 164 00:09:08,600 --> 00:09:11,840 Speaker 1: does the energy get from the photon into the material? 165 00:09:12,280 --> 00:09:14,480 Speaker 1: And the second is how can you construct a material 166 00:09:14,520 --> 00:09:17,320 Speaker 1: that it can effectively grab that energy and siphon it 167 00:09:17,360 --> 00:09:20,880 Speaker 1: off into electricity? And so the first step is called 168 00:09:20,920 --> 00:09:24,680 Speaker 1: the photovoltaic effect, or a photon hits a piece of 169 00:09:24,720 --> 00:09:28,079 Speaker 1: material and it basically passes that energy to an electron. 170 00:09:28,840 --> 00:09:32,880 Speaker 1: What does that mean, Like the electron absorbs the photon, 171 00:09:33,400 --> 00:09:36,480 Speaker 1: or like the photon hits the electron. How can I 172 00:09:36,559 --> 00:09:39,640 Speaker 1: visual life? Yeah, the photon is absorbed by the electron. 173 00:09:39,880 --> 00:09:43,640 Speaker 1: Remember that electrons interact electromagnetically, and that just means that 174 00:09:43,720 --> 00:09:47,959 Speaker 1: they trade photon. So every kind of electromagnetic interaction, every 175 00:09:48,000 --> 00:09:51,559 Speaker 1: push and pull by electric fields is mediated by photons. 176 00:09:51,600 --> 00:09:53,920 Speaker 1: So photons are the way that electrons talk to each 177 00:09:53,960 --> 00:09:58,040 Speaker 1: other and other charged particles. And photons are not eternal, right, 178 00:09:58,080 --> 00:10:00,760 Speaker 1: they can get absorbed by an electron, Their energy goes 179 00:10:01,400 --> 00:10:04,480 Speaker 1: right into the electron and then the electron has that energy. 180 00:10:04,920 --> 00:10:06,760 Speaker 1: So the way I visualize it as like a photon 181 00:10:06,840 --> 00:10:10,280 Speaker 1: coming in meets an electron and then only the electron continues. 182 00:10:10,960 --> 00:10:13,400 Speaker 1: So now the electron absorbs the photon and now I 183 00:10:13,440 --> 00:10:16,320 Speaker 1: guess it's charged up or something. Yeah, it's more exciting, exactly, 184 00:10:16,360 --> 00:10:18,800 Speaker 1: it's charged up. And there's two different effects here that 185 00:10:18,840 --> 00:10:21,800 Speaker 1: are very closely related. One is the photo voltaic effect, 186 00:10:21,800 --> 00:10:23,760 Speaker 1: which is what we're talking about, and the other is 187 00:10:23,920 --> 00:10:26,440 Speaker 1: something more famous that people might have heard about called 188 00:10:26,440 --> 00:10:29,959 Speaker 1: the photoelectric effect. They sound very similar and they are 189 00:10:30,160 --> 00:10:34,080 Speaker 1: very similar. Photoelectric effect it's when the photon has enough 190 00:10:34,200 --> 00:10:37,880 Speaker 1: energy that the electron gets kicked out of the materials. 191 00:10:37,920 --> 00:10:40,400 Speaker 1: So people saw this about a hundred years ago. If 192 00:10:40,440 --> 00:10:43,240 Speaker 1: you shine light at a material, you will get electrons 193 00:10:43,320 --> 00:10:45,440 Speaker 1: boiling off the surface, and that's because they have so 194 00:10:45,559 --> 00:10:48,800 Speaker 1: much energy they can leave the trap of the material, 195 00:10:49,360 --> 00:10:53,120 Speaker 1: meaning like a you know, an electron is orbiting the 196 00:10:53,200 --> 00:10:55,760 Speaker 1: nucleus of an atom because the nucleus is positive, but 197 00:10:55,800 --> 00:10:58,320 Speaker 1: now it has so much energy it just pops up. Yeah, 198 00:10:58,360 --> 00:11:01,160 Speaker 1: it just pops out. And this electric effect is actually 199 00:11:01,200 --> 00:11:04,600 Speaker 1: what Einstein won his Nobel Prize for explaining and was 200 00:11:04,640 --> 00:11:07,240 Speaker 1: one of the key experiments that led us to understand 201 00:11:07,600 --> 00:11:11,000 Speaker 1: that light is not just electromagnetic waves, what actually comes 202 00:11:11,040 --> 00:11:14,320 Speaker 1: in little particles, because we saw these weird relationships between 203 00:11:14,520 --> 00:11:16,920 Speaker 1: the intensity of the light and the wavelength and how 204 00:11:16,920 --> 00:11:19,320 Speaker 1: many electrons were boiled off. But we have a whole 205 00:11:19,320 --> 00:11:21,880 Speaker 1: other podcast episode about that about how we know that 206 00:11:21,960 --> 00:11:24,840 Speaker 1: light is quantized made out of these little photons. But 207 00:11:24,960 --> 00:11:28,360 Speaker 1: that's very similar to the photovoltaic effect. But the voltaic 208 00:11:28,440 --> 00:11:31,360 Speaker 1: effect is when the photon comes in and the electron 209 00:11:31,400 --> 00:11:34,760 Speaker 1: gets enough energy, but not enough to actually leave the material. 210 00:11:35,160 --> 00:11:37,560 Speaker 1: It gets excited, but it's still hanging out sort of 211 00:11:37,640 --> 00:11:40,199 Speaker 1: in the same blob of stuff I see. So it's 212 00:11:40,200 --> 00:11:42,760 Speaker 1: just a matter of whether or not it gets enough 213 00:11:42,840 --> 00:11:45,120 Speaker 1: energy to pop out, basically. Yeah, And there are some 214 00:11:45,200 --> 00:11:49,000 Speaker 1: materials where electrons don't have to be isolated to one 215 00:11:49,040 --> 00:11:51,880 Speaker 1: specific atom, like the picture you described as correct, you 216 00:11:51,920 --> 00:11:54,920 Speaker 1: have an electron it's orbiting a nucleus, for example, although 217 00:11:55,080 --> 00:11:57,280 Speaker 1: we don't really like to think of them as actually orbiting. 218 00:11:57,400 --> 00:12:00,520 Speaker 1: It's hanging around quantum mechanically near it's nuclear is. But 219 00:12:00,600 --> 00:12:03,360 Speaker 1: in lots of crystals, you have electrons that can flow 220 00:12:03,480 --> 00:12:07,000 Speaker 1: between atoms, and so, for example, in semiconductors, you have 221 00:12:07,040 --> 00:12:10,120 Speaker 1: electrons that are trapped that are around individual atoms, and 222 00:12:10,120 --> 00:12:12,600 Speaker 1: then if they get enough energy, they can jump up 223 00:12:12,640 --> 00:12:14,880 Speaker 1: over a little gap into a band where they can 224 00:12:14,920 --> 00:12:18,000 Speaker 1: move around more freely and jump from atom to atom. Yeah, 225 00:12:18,000 --> 00:12:20,120 Speaker 1: they sort of float around, right, They're not bound to 226 00:12:20,559 --> 00:12:24,200 Speaker 1: one atom. They can you know, hang out. Yeah, they're 227 00:12:24,200 --> 00:12:26,960 Speaker 1: like social butterflies. They just float around. They have enough energy, 228 00:12:27,240 --> 00:12:29,720 Speaker 1: they're sort of like flying high above all of these 229 00:12:29,720 --> 00:12:33,400 Speaker 1: little gaps. And so that's what happens in the photovoltaic effect, 230 00:12:33,440 --> 00:12:36,559 Speaker 1: that a phoeton comes in and knocks an electron off 231 00:12:36,640 --> 00:12:38,560 Speaker 1: from being stuck around one of the atoms, and so 232 00:12:38,600 --> 00:12:41,320 Speaker 1: they can float around free. Wait, that's the photo electric 233 00:12:41,440 --> 00:12:44,319 Speaker 1: or photovoltaic. Poto voltaic is when it knocks it off 234 00:12:44,320 --> 00:12:47,520 Speaker 1: so we can float around inside the material. Photo electric 235 00:12:47,760 --> 00:12:49,600 Speaker 1: is when it gets so much energy that it flies 236 00:12:49,679 --> 00:12:52,720 Speaker 1: free the material and out into space. It's like abandons 237 00:12:52,760 --> 00:12:56,240 Speaker 1: its original family. Oh, I see, I see you Like 238 00:12:56,280 --> 00:12:58,600 Speaker 1: one is like pop out out of the material, like 239 00:12:58,679 --> 00:13:02,960 Speaker 1: out out of like a way and bolt take it 240 00:13:03,080 --> 00:13:05,560 Speaker 1: leaves the atom. But it hangs out in the lattice, 241 00:13:05,600 --> 00:13:08,080 Speaker 1: in the structure of the material. Yeah, it's just jumping 242 00:13:08,080 --> 00:13:11,280 Speaker 1: around from atom to atom, floating free inside the material. 243 00:13:11,559 --> 00:13:14,439 Speaker 1: The photo electric effect, it's like totally liberated and may 244 00:13:14,480 --> 00:13:17,600 Speaker 1: never come back to home. All right. So that's the 245 00:13:17,679 --> 00:13:19,920 Speaker 1: two effects, and the one in solar panels is the 246 00:13:19,920 --> 00:13:23,320 Speaker 1: photovoltaic effect exactly. And so the key thing for solar 247 00:13:23,320 --> 00:13:25,920 Speaker 1: panels is to take advantage of the photovol take effect. 248 00:13:25,960 --> 00:13:28,600 Speaker 1: Because now you have this electron, it's got more energy. 249 00:13:28,880 --> 00:13:30,920 Speaker 1: If you could grab that energy somehow, if you could 250 00:13:30,920 --> 00:13:33,920 Speaker 1: funnel it into an electric current, then you could turn 251 00:13:34,160 --> 00:13:38,280 Speaker 1: effectively that photons energy into electricity. And so that's why 252 00:13:38,320 --> 00:13:40,520 Speaker 1: you need a special kind of material. Now, any kind 253 00:13:40,520 --> 00:13:43,240 Speaker 1: of material can have the photovol take effect. Your hand 254 00:13:43,480 --> 00:13:46,000 Speaker 1: or a rock or whatever. When it absorbs a photon, 255 00:13:46,360 --> 00:13:48,960 Speaker 1: the electrons that absorb it don't fly off the material. 256 00:13:49,360 --> 00:13:51,920 Speaker 1: Right then you're having the photovol take effect. You're grabbing 257 00:13:51,960 --> 00:13:54,320 Speaker 1: that energy into the object. But you need a special 258 00:13:54,400 --> 00:13:57,800 Speaker 1: kind of material to effectively gather that energy and funnel 259 00:13:57,800 --> 00:14:01,560 Speaker 1: it off into electricity. And that's where the silicon diode 260 00:14:01,600 --> 00:14:05,079 Speaker 1: comes in. And we had an a whole episode about diodes, right, 261 00:14:05,200 --> 00:14:08,000 Speaker 1: and transistors. Yeah, we did because we talked about how 262 00:14:08,120 --> 00:14:10,640 Speaker 1: L E d s work, and diodes are like a 263 00:14:10,800 --> 00:14:14,560 Speaker 1: really key foundational element of modern computing because you can 264 00:14:14,640 --> 00:14:16,599 Speaker 1: use them to make L D s and transistors and 265 00:14:16,640 --> 00:14:19,800 Speaker 1: all sorts of stuff. And it comes from semiconductors. And 266 00:14:19,840 --> 00:14:22,840 Speaker 1: that's why silicon is so important to the computing industry 267 00:14:23,080 --> 00:14:26,080 Speaker 1: because it's the most important semiconductor for building these kinds 268 00:14:26,080 --> 00:14:29,320 Speaker 1: of things, right, And it's important because it's kind of 269 00:14:29,320 --> 00:14:31,960 Speaker 1: a special material, right, Like it has just the right 270 00:14:32,080 --> 00:14:35,720 Speaker 1: number of loose electrons and it's pretty stable. Yeah, because 271 00:14:35,760 --> 00:14:38,480 Speaker 1: the electrons have these two different regimes they can be in. 272 00:14:38,800 --> 00:14:42,120 Speaker 1: A conductor is where the electrons just flow freely everywhere 273 00:14:42,120 --> 00:14:45,080 Speaker 1: from atom atom and insulator is one with the electrons 274 00:14:45,080 --> 00:14:48,000 Speaker 1: are all stuck around their individual atoms. And a semiconductor 275 00:14:48,040 --> 00:14:50,680 Speaker 1: is one that has both and has the electrons around 276 00:14:50,720 --> 00:14:53,400 Speaker 1: the atoms and electrons at a higher energy that can 277 00:14:53,440 --> 00:14:55,800 Speaker 1: hop freely from atom to atom. So that's what a 278 00:14:55,840 --> 00:14:58,640 Speaker 1: semiconductor is, and silicon is a great example of it. 279 00:14:59,120 --> 00:15:01,960 Speaker 1: And what happened and silicon is exactly that the electrons 280 00:15:02,040 --> 00:15:05,320 Speaker 1: jump over this band and then they can float around free. Yeah, 281 00:15:05,520 --> 00:15:07,680 Speaker 1: and so that's how you make a solar panel. As 282 00:15:07,720 --> 00:15:10,680 Speaker 1: you use silicon to make a solar panel. But and 283 00:15:10,680 --> 00:15:13,240 Speaker 1: then do you have to like create these different areas 284 00:15:13,240 --> 00:15:15,680 Speaker 1: where one one area is like a P type and 285 00:15:15,760 --> 00:15:17,600 Speaker 1: the other ones in N type. Yeah, you can't just 286 00:15:17,680 --> 00:15:20,200 Speaker 1: use normal silicon. You need to create something that's going 287 00:15:20,240 --> 00:15:23,080 Speaker 1: to funnel off the electrons. So the way that works 288 00:15:23,120 --> 00:15:25,720 Speaker 1: is that you have two different kinds of silicon. It's 289 00:15:25,720 --> 00:15:28,760 Speaker 1: not pure silicon. You've added stuff to it slightly to 290 00:15:28,880 --> 00:15:31,520 Speaker 1: change the behavior. And so you have one kind you 291 00:15:31,600 --> 00:15:34,600 Speaker 1: called N type, which has like extra electrons there are 292 00:15:34,640 --> 00:15:37,120 Speaker 1: a bunch of electrons floating around that sort of don't 293 00:15:37,160 --> 00:15:39,520 Speaker 1: have a chair to sit in if you played musical chairs. 294 00:15:39,920 --> 00:15:42,720 Speaker 1: And another kind where you've added other kinds of materials 295 00:15:42,720 --> 00:15:45,840 Speaker 1: like gallium or arsenide or whatever. So they're called P type. 296 00:15:45,880 --> 00:15:48,800 Speaker 1: They don't have enough electrons. They're like empty spots for 297 00:15:48,880 --> 00:15:52,600 Speaker 1: electrons to sit in. And semiconductor physicists they talk about 298 00:15:52,640 --> 00:15:55,120 Speaker 1: these things as holes, and they treat them as if 299 00:15:55,120 --> 00:15:58,040 Speaker 1: they're sort of like positively charged electrons. They think of 300 00:15:58,080 --> 00:16:01,080 Speaker 1: them sort of like as particles. I remember we talked 301 00:16:01,080 --> 00:16:04,160 Speaker 1: about the quasi particles like things that are not particles 302 00:16:04,160 --> 00:16:06,120 Speaker 1: but sort of act like particles. This is a good 303 00:16:06,160 --> 00:16:08,600 Speaker 1: example of one. It's a hole. It's like a missing 304 00:16:08,680 --> 00:16:11,280 Speaker 1: spot for a particle, but it moves around sort of 305 00:16:11,400 --> 00:16:14,240 Speaker 1: as if it was a positively charged particle. Right. It's 306 00:16:14,240 --> 00:16:16,400 Speaker 1: like if you had five people for six chairs and 307 00:16:16,480 --> 00:16:19,160 Speaker 1: they move around and change seats. It's like you keep 308 00:16:19,200 --> 00:16:22,120 Speaker 1: track of worth of the empty seat, not the people. Yeah, 309 00:16:22,160 --> 00:16:24,880 Speaker 1: and the empty seat moves like a particle, right, because 310 00:16:24,920 --> 00:16:27,200 Speaker 1: if one person slides from one seat to the other, 311 00:16:27,360 --> 00:16:30,440 Speaker 1: then the empty spot slides the other direction. Sort of 312 00:16:30,520 --> 00:16:32,480 Speaker 1: cool to have that idea in your mind of an 313 00:16:32,480 --> 00:16:36,200 Speaker 1: emptiness being a thing. Anyway, So you have these two 314 00:16:36,320 --> 00:16:38,440 Speaker 1: kinds of the lookon the P type that has extra 315 00:16:38,480 --> 00:16:42,240 Speaker 1: holes and the end type that has extra electrons, And 316 00:16:42,320 --> 00:16:45,280 Speaker 1: because they match up together, there's the sort of you know, 317 00:16:45,360 --> 00:16:47,760 Speaker 1: too much electrons on one side and too many holes 318 00:16:47,760 --> 00:16:50,880 Speaker 1: in the other. Some of the electrons flow across the 319 00:16:51,000 --> 00:16:53,720 Speaker 1: junction between them and fill up some of the holes 320 00:16:53,720 --> 00:16:56,640 Speaker 1: on the other side, and that makes an electric field 321 00:16:56,680 --> 00:16:59,520 Speaker 1: across them. That's the key thing. The electrons have flowed 322 00:16:59,560 --> 00:17:01,600 Speaker 1: in one to action, and now they make an electric 323 00:17:01,640 --> 00:17:04,439 Speaker 1: field going the other way right. I think what happens 324 00:17:04,480 --> 00:17:07,119 Speaker 1: is that like the material that has too many electrons 325 00:17:07,600 --> 00:17:10,040 Speaker 1: loses some of them because they all go to the 326 00:17:10,080 --> 00:17:12,240 Speaker 1: side that has the holes. And now you have like 327 00:17:12,280 --> 00:17:15,680 Speaker 1: this build up of too much too many electrons in 328 00:17:15,680 --> 00:17:18,119 Speaker 1: in one place, and so that creates like a like 329 00:17:18,160 --> 00:17:22,080 Speaker 1: a barrier, like a something that repels other electrons. Yeah, exactly. 330 00:17:22,080 --> 00:17:25,080 Speaker 1: It's sort of like you know, diffusion of temperature. If 331 00:17:25,080 --> 00:17:26,560 Speaker 1: a hot thing next to a cold thing, then the 332 00:17:26,560 --> 00:17:29,000 Speaker 1: heat's going to flow over the cold side. And so 333 00:17:29,080 --> 00:17:31,320 Speaker 1: you put this N type stuff with too many electrons 334 00:17:31,400 --> 00:17:34,080 Speaker 1: next to the P type stuff without enough electrons, some 335 00:17:34,119 --> 00:17:36,960 Speaker 1: of them flow over, and you're right, it creates this barrier. 336 00:17:37,400 --> 00:17:40,040 Speaker 1: So now you have this P N junction, you have 337 00:17:40,040 --> 00:17:42,440 Speaker 1: the silk, and it's all primed to get your photon. 338 00:17:42,480 --> 00:17:45,680 Speaker 1: Because what happens when a photon hits this special diode, 339 00:17:45,680 --> 00:17:48,760 Speaker 1: this combination of P type and N type silicon, is 340 00:17:48,800 --> 00:17:51,399 Speaker 1: that when the electron gets kicked free, it doesn't just 341 00:17:51,440 --> 00:17:54,719 Speaker 1: wander around loosely. Is now an electric field created by 342 00:17:54,760 --> 00:17:57,960 Speaker 1: the P N junction that pushes the electron all away 343 00:17:58,000 --> 00:18:00,119 Speaker 1: in one direction, and then you just have to have 344 00:18:00,240 --> 00:18:02,800 Speaker 1: something at the edge there to gather these electrons, these 345 00:18:02,800 --> 00:18:06,239 Speaker 1: electrons that have the solar energy absorbed, so they can 346 00:18:06,280 --> 00:18:10,240 Speaker 1: move along and create electric current. All right, well, I 347 00:18:10,320 --> 00:18:12,679 Speaker 1: have some questions about that, and let's get into some 348 00:18:12,760 --> 00:18:15,120 Speaker 1: of the details in and also maybe let's talk about 349 00:18:15,119 --> 00:18:18,280 Speaker 1: some of the larger issues about solar panels. But first, 350 00:18:18,359 --> 00:18:34,920 Speaker 1: let's take a quick break. Right. We're talking about solar 351 00:18:34,960 --> 00:18:38,000 Speaker 1: panels and how they work, and they do work, they're 352 00:18:38,040 --> 00:18:40,320 Speaker 1: pretty good. I have some how Well, do your solar 353 00:18:40,320 --> 00:18:43,520 Speaker 1: panels work? You generate enough electricity for your house every day? Yeah? 354 00:18:43,560 --> 00:18:45,920 Speaker 1: In fact, they generate so much energy we get a 355 00:18:46,000 --> 00:18:48,879 Speaker 1: check from the electric company. They're like, you gave up 356 00:18:48,920 --> 00:18:52,320 Speaker 1: too much electricity. Here's some money back, and your energy 357 00:18:52,359 --> 00:18:55,399 Speaker 1: goes back to the electric company and then back to 358 00:18:55,440 --> 00:18:58,119 Speaker 1: your house. Right. You don't directly use the electricity created 359 00:18:58,160 --> 00:19:00,360 Speaker 1: on your roof, do you, right? Yeah? No, I don't 360 00:19:00,400 --> 00:19:02,480 Speaker 1: have a battery, So it just goes back into the 361 00:19:02,520 --> 00:19:04,679 Speaker 1: grid and then we get from the grid. But they 362 00:19:04,720 --> 00:19:06,960 Speaker 1: keep track and if we make more than we take, 363 00:19:07,080 --> 00:19:09,880 Speaker 1: then they give us a small amount of money for them. Awesome. Yeah, 364 00:19:09,960 --> 00:19:11,760 Speaker 1: So we were talking about how it works, and it 365 00:19:11,880 --> 00:19:16,720 Speaker 1: involves silicon and p type and type of materials that 366 00:19:16,800 --> 00:19:19,760 Speaker 1: have holes and extra electrons, and so is the idea 367 00:19:19,840 --> 00:19:21,919 Speaker 1: then that you know, the side that has too many 368 00:19:21,960 --> 00:19:24,959 Speaker 1: electrons gives them to the side that doesn't have enough electrons, 369 00:19:25,640 --> 00:19:28,320 Speaker 1: and that creates kind of like a like a standoff 370 00:19:28,400 --> 00:19:31,280 Speaker 1: almost like a barrier for any more electrons to flow. 371 00:19:31,400 --> 00:19:34,040 Speaker 1: But once the light comes in, then that kind of 372 00:19:34,119 --> 00:19:37,360 Speaker 1: kicks things up. Yeah, and then these new electrons get 373 00:19:37,400 --> 00:19:40,600 Speaker 1: pushed away from that barrier as you said, and towards 374 00:19:40,600 --> 00:19:43,080 Speaker 1: the edge, and then they get gathered up and the 375 00:19:43,240 --> 00:19:46,280 Speaker 1: current forms with all these energetic electrons and you can 376 00:19:46,359 --> 00:19:49,760 Speaker 1: draw that off. And that's basically what electricity is. It's 377 00:19:49,840 --> 00:19:53,639 Speaker 1: energetic electrons. It's electrons moving along. That's what current is. 378 00:19:53,680 --> 00:19:57,160 Speaker 1: It's just the motion of charged particles. It feels kind 379 00:19:57,160 --> 00:19:59,680 Speaker 1: of like almost like magic. I mean, like the sunlight 380 00:19:59,800 --> 00:20:04,080 Speaker 1: is actually creating energy, is just kind of like triggering 381 00:20:04,359 --> 00:20:07,239 Speaker 1: the flow of energy. Yeah, well, sunlight is energy, right, 382 00:20:07,400 --> 00:20:09,800 Speaker 1: It's energy that was released from the fusion of hydrogen 383 00:20:09,840 --> 00:20:11,720 Speaker 1: into helium in the center of the sun and that 384 00:20:11,840 --> 00:20:15,919 Speaker 1: has been flying nine million miles through space. And the 385 00:20:15,960 --> 00:20:18,639 Speaker 1: cool thing is that that energy doesn't like evaporate or 386 00:20:18,720 --> 00:20:21,639 Speaker 1: run out. You know, photons can fly through space basically 387 00:20:21,720 --> 00:20:25,560 Speaker 1: forever without losing any energy, doesn't take them any energy 388 00:20:25,600 --> 00:20:27,760 Speaker 1: to fly the speed of light, and then that energy 389 00:20:27,760 --> 00:20:31,119 Speaker 1: gets deposited, you know, on your solar cell and gets 390 00:20:31,119 --> 00:20:34,040 Speaker 1: slurped up into that electron. It's really pretty awesome, and 391 00:20:34,080 --> 00:20:35,800 Speaker 1: the coolest thing about it, I think is that it's 392 00:20:35,880 --> 00:20:38,520 Speaker 1: quantum mechanics. You know, this is not something you can 393 00:20:38,560 --> 00:20:41,520 Speaker 1: explain with classical physics. So it's something we only could 394 00:20:41,560 --> 00:20:45,920 Speaker 1: have invented pretty recently. Well, we we understand it now, 395 00:20:46,000 --> 00:20:49,880 Speaker 1: but didn't we sort of invented before understanding how it works? Yeah, 396 00:20:49,920 --> 00:20:51,879 Speaker 1: you're right, we understand it now, which allows us to 397 00:20:51,920 --> 00:20:54,520 Speaker 1: like optimize it. And we certainly never could have built 398 00:20:54,560 --> 00:20:58,720 Speaker 1: like these complicated p N junctions without understanding quantum mechanics. 399 00:20:58,880 --> 00:21:01,280 Speaker 1: But I suppose some clever engineer could have put it 400 00:21:01,280 --> 00:21:06,560 Speaker 1: together without a deep physics understanding. Suppose, like I guess, 401 00:21:07,119 --> 00:21:10,480 Speaker 1: if they were like a super special genius engineer. You're 402 00:21:10,560 --> 00:21:12,840 Speaker 1: you're absolutely right. And there's lots of examples of times 403 00:21:12,840 --> 00:21:15,679 Speaker 1: when we build something we saw do something cool and 404 00:21:15,720 --> 00:21:18,240 Speaker 1: we didn't understand what was happening, and that led to 405 00:21:18,280 --> 00:21:20,760 Speaker 1: lots of really awesome questions, you know, like that's how 406 00:21:20,760 --> 00:21:24,120 Speaker 1: electrons were discovered. People didn't understand crooks tubes and these 407 00:21:24,359 --> 00:21:26,600 Speaker 1: glowing rays they saw inside them, and so it led 408 00:21:26,640 --> 00:21:29,000 Speaker 1: to lots of awesome stuff. So yes, absolutely, you can 409 00:21:29,040 --> 00:21:31,280 Speaker 1: build stuff before you understand it. It It is pretty cool 410 00:21:31,320 --> 00:21:33,200 Speaker 1: to the thing now that you mentioned it. It's amazing 411 00:21:33,240 --> 00:21:36,320 Speaker 1: how like these photons were made in the Sun and 412 00:21:36,359 --> 00:21:41,639 Speaker 1: they traveled millions of miles really sort of uninterrupted, like 413 00:21:41,680 --> 00:21:44,040 Speaker 1: they don't lose any energy in the way. It's like 414 00:21:44,119 --> 00:21:46,800 Speaker 1: almost like a perfect transmission. And then they hit my 415 00:21:46,840 --> 00:21:50,520 Speaker 1: solar panel and powers my devices. Yeah, exactly. So really, 416 00:21:50,520 --> 00:21:53,560 Speaker 1: solar power is fusion power. You know. It's just like 417 00:21:53,920 --> 00:21:57,680 Speaker 1: you are a blanket to absorb energy from a fusion device. 418 00:21:57,720 --> 00:21:59,479 Speaker 1: We talked about either a few weeks ago and how 419 00:21:59,480 --> 00:22:02,119 Speaker 1: a big problem they have is how to absorb the 420 00:22:02,240 --> 00:22:05,760 Speaker 1: energy that either creates, like haven't really tackled that problem yet, 421 00:22:06,160 --> 00:22:08,320 Speaker 1: And you're basically doing that for the Sun. You know, 422 00:22:08,400 --> 00:22:11,119 Speaker 1: the Sun is this huge fusion engine and you're putting 423 00:22:11,160 --> 00:22:13,359 Speaker 1: up a little panel to grab a tiny little slice 424 00:22:13,400 --> 00:22:15,280 Speaker 1: of all. Man. I wonder how much any more panels 425 00:22:15,280 --> 00:22:18,040 Speaker 1: they would sell. They called it dead. You know, fusion 426 00:22:18,080 --> 00:22:26,160 Speaker 1: panels probably fewer fusian generator on the roof, a hydrogen 427 00:22:26,200 --> 00:22:30,320 Speaker 1: bomb on your roof where your kids sleep. Who doesn't 428 00:22:30,320 --> 00:22:34,040 Speaker 1: want their computer, their work powered by fusion energy? Me? 429 00:22:34,280 --> 00:22:37,359 Speaker 1: I don't. No, No, honestly I do. That's super awesome. 430 00:22:37,440 --> 00:22:40,600 Speaker 1: I think it's wonderful. And also it works pretty well. 431 00:22:40,720 --> 00:22:43,159 Speaker 1: You know, it's sort of shocking how efficient it is. 432 00:22:44,000 --> 00:22:46,480 Speaker 1: But I mean, what's the efficiency. Well, the record efficiency 433 00:22:46,520 --> 00:22:49,640 Speaker 1: for like the most highly engineered solar panels so far 434 00:22:49,800 --> 00:22:53,720 Speaker 1: is about forty that's the fraction of the energy of 435 00:22:53,760 --> 00:22:56,800 Speaker 1: the photons coming in that you can effectively gather out 436 00:22:56,840 --> 00:23:00,240 Speaker 1: as electricity. And that's pretty good. That's like a one 437 00:23:00,240 --> 00:23:03,720 Speaker 1: out of every two holdons you actually use it for something. Yeah, 438 00:23:03,880 --> 00:23:06,400 Speaker 1: And it's not a hundred percent efficient because not all 439 00:23:06,480 --> 00:23:09,679 Speaker 1: the energy goes into one electron, or that electron loses 440 00:23:09,680 --> 00:23:12,280 Speaker 1: some of its energy along the way as it moves 441 00:23:12,320 --> 00:23:14,760 Speaker 1: along through the silicon and gets to the thing that 442 00:23:14,880 --> 00:23:17,160 Speaker 1: stirps it out, or it goes into you know, exciting 443 00:23:17,200 --> 00:23:20,000 Speaker 1: the nucleus or stuff like that. And most devices that 444 00:23:20,000 --> 00:23:21,800 Speaker 1: you would have on your roof are not that efficient. 445 00:23:21,840 --> 00:23:24,920 Speaker 1: Mostly they're like fifteen to twenty percent efficient, though they've 446 00:23:24,920 --> 00:23:27,760 Speaker 1: climbed a lot in recent years. It's incredible the prices 447 00:23:27,800 --> 00:23:31,280 Speaker 1: are dropping and the efficiencies are rising, and even is 448 00:23:31,320 --> 00:23:34,399 Speaker 1: really pretty efficient. Yeah, what happens to the other percent? 449 00:23:34,560 --> 00:23:37,600 Speaker 1: Like where does all the other energy go gets reflected 450 00:23:37,840 --> 00:23:40,560 Speaker 1: or absorbed? It just goes into heating the material. You know, 451 00:23:40,600 --> 00:23:43,480 Speaker 1: there's lots of ways for silicon to absorb energy, not 452 00:23:43,600 --> 00:23:46,560 Speaker 1: just one electron getting kicked up an energy level. The 453 00:23:46,640 --> 00:23:49,520 Speaker 1: nucleus can absorb energy, or the electron can absorb the 454 00:23:49,600 --> 00:23:52,120 Speaker 1: energy and then lose it to something else, and so 455 00:23:52,240 --> 00:23:55,400 Speaker 1: there's a lot of delicate engineering involved in getting those 456 00:23:55,440 --> 00:23:57,840 Speaker 1: electrons to be the place where the energy lands and 457 00:23:58,000 --> 00:24:00,760 Speaker 1: getting them to deliver it to the edge of the 458 00:24:00,880 --> 00:24:03,240 Speaker 1: p N junction. You know, this stuff is really cool 459 00:24:03,280 --> 00:24:05,560 Speaker 1: because it's actually very similar to what we do with 460 00:24:05,600 --> 00:24:09,440 Speaker 1: the large Hadron collider. We use silicon devices to detect 461 00:24:09,480 --> 00:24:13,240 Speaker 1: the passage of particles photons but also like muans or 462 00:24:13,280 --> 00:24:16,840 Speaker 1: other particles, and you detect particles in exactly this same way. 463 00:24:17,080 --> 00:24:19,919 Speaker 1: The particle passes through the detector and it leaves a 464 00:24:20,000 --> 00:24:23,399 Speaker 1: trail of electrons behind it, which we then slurp off 465 00:24:23,480 --> 00:24:26,119 Speaker 1: and use that as evidence to say, hey, there was 466 00:24:26,160 --> 00:24:29,560 Speaker 1: a particle that passed through, So we should maybe think 467 00:24:29,600 --> 00:24:32,640 Speaker 1: about rebranding it that way too, Like, don't call them 468 00:24:32,720 --> 00:24:38,120 Speaker 1: solar panels, call them melon absorbers, particle detectors, particles. Yeah, 469 00:24:38,160 --> 00:24:41,199 Speaker 1: who doesn't want a particle detector on the roof? And 470 00:24:41,240 --> 00:24:44,159 Speaker 1: you know the same basic principle works also in every 471 00:24:44,200 --> 00:24:47,600 Speaker 1: digital camera, right, That's how digital camera turns a photon, 472 00:24:48,160 --> 00:24:51,479 Speaker 1: which is the picture you're seeing, into an electrical signal, 473 00:24:51,480 --> 00:24:53,960 Speaker 1: which is what your computer needs to record it. The 474 00:24:54,000 --> 00:24:57,240 Speaker 1: photovo take effect. It turns a photon into little electrons 475 00:24:57,240 --> 00:24:59,360 Speaker 1: which then get gathered up at the edge of your 476 00:24:59,400 --> 00:25:02,760 Speaker 1: little pixel and recorded as evidences stead of photon came 477 00:25:02,760 --> 00:25:06,440 Speaker 1: through as like, oh, that's right. Yeah, that means everyone 478 00:25:06,480 --> 00:25:08,760 Speaker 1: who has a camera on their phone has a solar 479 00:25:08,800 --> 00:25:12,800 Speaker 1: panel in their pocket. That's right, that's right, except that 480 00:25:12,840 --> 00:25:16,480 Speaker 1: it draws power instead of generating it. Unfortunately, it generates images, 481 00:25:16,760 --> 00:25:18,560 Speaker 1: but it doesn't generate power. Does I mean I have 482 00:25:18,600 --> 00:25:21,480 Speaker 1: a giant camera on my roof taking pictures of the 483 00:25:21,520 --> 00:25:23,800 Speaker 1: sun every day? Absolutely? And you know we have done 484 00:25:23,800 --> 00:25:27,879 Speaker 1: the calculations. Can you use solar panels as particle detectors? 485 00:25:28,080 --> 00:25:30,879 Speaker 1: Could we use everybody's solar panels? Is like a huge 486 00:25:30,960 --> 00:25:35,080 Speaker 1: telescope to understand cosmic rays. Unfortunately you can't because you're 487 00:25:35,080 --> 00:25:37,520 Speaker 1: swamped by the photons from the Sun which make a 488 00:25:37,600 --> 00:25:40,200 Speaker 1: huge signal. And everything else we're interested in, like little 489 00:25:40,240 --> 00:25:44,320 Speaker 1: muans or positrons or protons, is swamped by that huge 490 00:25:44,440 --> 00:25:47,080 Speaker 1: blinding light from the sun. But it does you're you're saying, 491 00:25:47,080 --> 00:25:51,080 Speaker 1: my solar panels do detect these other particles. It is 492 00:25:51,119 --> 00:25:53,879 Speaker 1: technically like catching them and converting them to a signal. 493 00:25:53,960 --> 00:25:56,560 Speaker 1: It totally is. If you covered your solar panels, if 494 00:25:56,560 --> 00:25:58,840 Speaker 1: you made them light proof, which would be terrible for 495 00:25:58,880 --> 00:26:01,679 Speaker 1: your electrical efficiency, But if you made them light proof 496 00:26:01,760 --> 00:26:03,919 Speaker 1: and cover them up so they were in a black box, 497 00:26:04,240 --> 00:26:07,000 Speaker 1: then they would be great detectors for muans or other 498 00:26:07,080 --> 00:26:12,440 Speaker 1: kinds of particles that could penetrate that seal and leave energy. Interesting. 499 00:26:12,640 --> 00:26:15,960 Speaker 1: All right, I am ready to do scientific experiments at 500 00:26:16,000 --> 00:26:22,160 Speaker 1: the expense of actually generating any electricity. Wow, some sacrifices 501 00:26:22,359 --> 00:26:24,879 Speaker 1: might have to be made. How important is science to you? 502 00:26:25,000 --> 00:26:27,200 Speaker 1: All right? Well, um, that's sort of how they work. 503 00:26:27,280 --> 00:26:30,840 Speaker 1: I guess. Maybe a question is they're pretty great, but 504 00:26:30,920 --> 00:26:33,240 Speaker 1: why aren't there more of them out there? Why doesn't 505 00:26:33,480 --> 00:26:38,720 Speaker 1: everyone jump into this solar energy bandwagon. Is it political 506 00:26:39,000 --> 00:26:41,639 Speaker 1: or are there other limitations? There are some other limitations. 507 00:26:41,680 --> 00:26:44,440 Speaker 1: You're right there, pretty great, but there are some downsides 508 00:26:44,480 --> 00:26:47,000 Speaker 1: to solar panels. One is that the sun is not 509 00:26:47,160 --> 00:26:50,199 Speaker 1: always above you in the sky. Right, Sometimes there are 510 00:26:50,280 --> 00:26:54,399 Speaker 1: clouds or it's night time, and so you're generating power 511 00:26:54,480 --> 00:26:56,960 Speaker 1: whenever the sun is above your solar panels. But that's 512 00:26:56,960 --> 00:27:00,280 Speaker 1: not always the case, and you need power some times 513 00:27:00,320 --> 00:27:02,760 Speaker 1: at night or when it's cloudy, and so you need 514 00:27:02,800 --> 00:27:07,119 Speaker 1: a complicated system there to buffer, to gather energy into 515 00:27:07,160 --> 00:27:08,960 Speaker 1: like a battery, and to save it for you for 516 00:27:09,119 --> 00:27:11,399 Speaker 1: when you need it. Right, But that's not really a negative. 517 00:27:11,440 --> 00:27:13,320 Speaker 1: It just means that, you know, you need a like 518 00:27:13,359 --> 00:27:15,760 Speaker 1: a buffer, you need like a something that stores it 519 00:27:15,840 --> 00:27:18,160 Speaker 1: like a battery. Yeah, but it adds to the cost, 520 00:27:18,520 --> 00:27:21,280 Speaker 1: you know, just like the transport issues. Say, for example, 521 00:27:21,400 --> 00:27:24,240 Speaker 1: you have a huge solar panel array out in the 522 00:27:24,320 --> 00:27:27,000 Speaker 1: desert to gather energy really efficiently, then you need to 523 00:27:27,080 --> 00:27:30,040 Speaker 1: send that energy hundreds or thousands of miles to where 524 00:27:30,080 --> 00:27:32,760 Speaker 1: it needs to go because you have a mismatch sometimes 525 00:27:32,800 --> 00:27:35,080 Speaker 1: between where the energy is used and where the energy 526 00:27:35,160 --> 00:27:37,840 Speaker 1: is created. I mean, if every device could just create 527 00:27:37,920 --> 00:27:41,080 Speaker 1: solar power whenever it needed it wherever it was. That 528 00:27:41,119 --> 00:27:43,480 Speaker 1: would be awesome. But one of the main costs of 529 00:27:43,480 --> 00:27:46,840 Speaker 1: solar power is fabricating the devices themselves, of course, which 530 00:27:46,880 --> 00:27:50,000 Speaker 1: is not trivial and not cheap, but also transporting and 531 00:27:50,040 --> 00:27:53,360 Speaker 1: buffering building these batteries. You know, battery technology is complicated 532 00:27:53,440 --> 00:27:56,520 Speaker 1: and also quite toxic, right, but I think that you 533 00:27:56,560 --> 00:27:58,760 Speaker 1: know you need to do these things anyways for any 534 00:27:58,800 --> 00:28:01,120 Speaker 1: kind of power, don't you Like, do you still need 535 00:28:01,119 --> 00:28:08,120 Speaker 1: the infrastructure for um, burning coal or for nuclear powered energy? Right? Well, 536 00:28:08,160 --> 00:28:10,640 Speaker 1: you know you can turn your coal power plant on 537 00:28:10,720 --> 00:28:13,520 Speaker 1: any time of day or night, right, and so it 538 00:28:13,560 --> 00:28:15,600 Speaker 1: can be a much steadier source of power doesn't have 539 00:28:15,640 --> 00:28:17,840 Speaker 1: these fluctuations. You don't need the same kind of buffer 540 00:28:18,240 --> 00:28:20,679 Speaker 1: for a coal power plant. A coal power plant, essentially 541 00:28:20,720 --> 00:28:22,879 Speaker 1: the energy is already in a battery. That battery is 542 00:28:22,880 --> 00:28:25,520 Speaker 1: called coal, and it's available for whenever you need it. 543 00:28:25,520 --> 00:28:28,359 Speaker 1: You just have to transform it into electricity. Now, of course, 544 00:28:28,600 --> 00:28:31,199 Speaker 1: coal is terrible for lots of other reasons. I'm not 545 00:28:31,320 --> 00:28:34,320 Speaker 1: selling coal. But one of the disadvantages of solar power 546 00:28:34,720 --> 00:28:37,720 Speaker 1: is that it's not always created when you need it, right, right, 547 00:28:37,880 --> 00:28:42,280 Speaker 1: But fortunately I'm mostly asleep at night. Well, actually, that's 548 00:28:42,280 --> 00:28:44,800 Speaker 1: not true for me, but I think for most of humanity, 549 00:28:45,240 --> 00:28:47,120 Speaker 1: you're sort of asleep at night, so you don't actually 550 00:28:47,200 --> 00:28:49,680 Speaker 1: use that much energy at night, right, and it's cooler 551 00:28:49,680 --> 00:28:52,200 Speaker 1: and you so you don't need the a C. Really like, 552 00:28:52,240 --> 00:28:56,080 Speaker 1: I think most people's power consumption matches sort of daylight. Yeah. 553 00:28:56,120 --> 00:28:58,600 Speaker 1: Do you use less power when it's cloudy outside, Yeah, 554 00:28:58,600 --> 00:29:00,680 Speaker 1: because you know you don't need to your house as 555 00:29:00,760 --> 00:29:02,960 Speaker 1: much right now, You're absolutely right. It's not a killer 556 00:29:03,000 --> 00:29:04,880 Speaker 1: for solar power for sure. It just means, you know, 557 00:29:04,920 --> 00:29:07,360 Speaker 1: you have to build this infrastructure and you have to 558 00:29:07,400 --> 00:29:09,760 Speaker 1: have batteries, you have to do this kind of stuff. 559 00:29:10,160 --> 00:29:13,080 Speaker 1: But you're right, people use more energy when it's daytime, 560 00:29:13,200 --> 00:29:15,680 Speaker 1: and they need more A C when it's sunny outside, 561 00:29:15,880 --> 00:29:18,040 Speaker 1: and so that's not that big an issue. Well, obviously 562 00:29:18,200 --> 00:29:22,240 Speaker 1: it's not like free energy, and it's not super simple 563 00:29:22,320 --> 00:29:25,160 Speaker 1: to get solar energy, but it's still I think overall, 564 00:29:25,280 --> 00:29:29,000 Speaker 1: it's it's renewable, right, and we don't create carbon emissions, 565 00:29:29,080 --> 00:29:34,800 Speaker 1: and still more positive than most other sources of energy, right, absolutely, 566 00:29:34,840 --> 00:29:36,840 Speaker 1: And it's getting cheaper, you know, the more we work 567 00:29:36,880 --> 00:29:39,880 Speaker 1: on it, the easier it is to fabricate these solar panels, 568 00:29:39,920 --> 00:29:42,680 Speaker 1: they last longer, they're more efficient, they're cheaper, they're easier 569 00:29:42,720 --> 00:29:46,280 Speaker 1: to produce, and it's sort of something that builds on itself. 570 00:29:46,520 --> 00:29:48,680 Speaker 1: The larger the market is, the more companies get involved, 571 00:29:48,680 --> 00:29:51,520 Speaker 1: the more competition there is, the more clever engineers get 572 00:29:51,520 --> 00:29:55,000 Speaker 1: on board from making these things effective, the better batteries get. 573 00:29:55,200 --> 00:29:57,600 Speaker 1: It seems like an excellent option for the future. It 574 00:29:57,680 --> 00:30:00,000 Speaker 1: just takes sort of an investment. It just takes us 575 00:30:00,080 --> 00:30:02,680 Speaker 1: deciding to make this happen. Yeah, and it's like we're 576 00:30:02,680 --> 00:30:06,040 Speaker 1: getting this energy from space for free. It feels great 577 00:30:06,080 --> 00:30:08,520 Speaker 1: to you. It does, and there's lots of really fun 578 00:30:08,560 --> 00:30:10,680 Speaker 1: ideas for how you could tap into it. You know, 579 00:30:10,760 --> 00:30:14,000 Speaker 1: you don't need to build a huge array of solar 580 00:30:14,000 --> 00:30:16,080 Speaker 1: panels in the middle of your city. You can put 581 00:30:16,120 --> 00:30:18,520 Speaker 1: them in the desert. We have lots of huge areas 582 00:30:18,560 --> 00:30:21,120 Speaker 1: of the earth where nobody's living because it's just sand, 583 00:30:21,520 --> 00:30:24,680 Speaker 1: and you could put vast solar arrays there. You can 584 00:30:24,720 --> 00:30:27,400 Speaker 1: even have them like floating on things in the ocean, 585 00:30:27,520 --> 00:30:30,560 Speaker 1: just gathering up solar energy. So if you built enough 586 00:30:30,600 --> 00:30:33,440 Speaker 1: infrastructure there, you could really power a lot of our 587 00:30:33,480 --> 00:30:36,160 Speaker 1: civilization's energy needs. Yeah, and create a lot of shade 588 00:30:36,160 --> 00:30:38,760 Speaker 1: in the desert, which would be pretty good probably for 589 00:30:38,800 --> 00:30:43,200 Speaker 1: all the animals there. All right, well that's sort of 590 00:30:43,200 --> 00:30:46,000 Speaker 1: the big picture and the little picture of solar power. 591 00:30:46,080 --> 00:30:48,120 Speaker 1: And we're gonna do something a little bit interesting next, 592 00:30:48,160 --> 00:30:51,440 Speaker 1: which is compare them to photo synthesis. But first, let's 593 00:30:51,480 --> 00:31:06,080 Speaker 1: take a quick break. All right, we're talking about solar power, 594 00:31:06,480 --> 00:31:09,880 Speaker 1: and we talked about how solar panels work, and so, Daniel, 595 00:31:09,880 --> 00:31:12,440 Speaker 1: you thought something interesting would be too, sort of compare 596 00:31:12,520 --> 00:31:15,480 Speaker 1: this man made machine and device that we've made to 597 00:31:15,560 --> 00:31:19,840 Speaker 1: capture solar energy to what nature has done. Plants use 598 00:31:20,120 --> 00:31:24,040 Speaker 1: solar power and so through something called photosynthesis, And so 599 00:31:24,080 --> 00:31:26,160 Speaker 1: how do the two compare. Do they use a similar 600 00:31:26,160 --> 00:31:29,240 Speaker 1: mechanism or is it totally different? Yeah? I thought this 601 00:31:29,320 --> 00:31:31,880 Speaker 1: was really fascinating because, you know, we've been working on 602 00:31:31,880 --> 00:31:35,600 Speaker 1: this technology for decades, but nature has been doing this 603 00:31:35,680 --> 00:31:39,200 Speaker 1: for literally billions of years, and it's got a really 604 00:31:39,240 --> 00:31:42,320 Speaker 1: refined process for making things more efficient and more effective 605 00:31:42,320 --> 00:31:45,520 Speaker 1: in finding solutions. And so naively, I thought to myself, well, 606 00:31:45,800 --> 00:31:48,400 Speaker 1: I'm sure that our efficiency is pretty good, but Nature's 607 00:31:48,400 --> 00:31:51,240 Speaker 1: efficiency must be even higher because it's been fine tuned 608 00:31:51,280 --> 00:31:53,840 Speaker 1: for for so long. But you know, you start to 609 00:31:53,840 --> 00:31:57,520 Speaker 1: read about photosynthesis, and you discover that it's actually less efficient, 610 00:31:57,760 --> 00:32:00,479 Speaker 1: that a smaller fraction of the light that comes from 611 00:32:00,520 --> 00:32:03,959 Speaker 1: the sun and hits a plant gets turned eventually into energy, 612 00:32:04,400 --> 00:32:07,600 Speaker 1: and it's using a completely different process. So they're not 613 00:32:07,640 --> 00:32:11,120 Speaker 1: as good as solar panels, I guess, and absorbing energy, 614 00:32:11,360 --> 00:32:13,480 Speaker 1: I guess. They don't have the advantage of like having 615 00:32:13,520 --> 00:32:17,600 Speaker 1: silicon and all these dope materials and highly engineered materials. 616 00:32:17,880 --> 00:32:20,840 Speaker 1: How do they work? How do plants absorb? Some might Yeah, 617 00:32:20,880 --> 00:32:23,440 Speaker 1: you're right. The plants don't necessarily have access to some 618 00:32:23,480 --> 00:32:25,800 Speaker 1: of the rarer elements that we use to dope our 619 00:32:25,880 --> 00:32:28,920 Speaker 1: silicon to make these diodes work. What they do is 620 00:32:29,040 --> 00:32:31,800 Speaker 1: they have the light come in and it interacts with 621 00:32:31,920 --> 00:32:35,640 Speaker 1: carbon dioxide and water inside the leaf, and essentially what 622 00:32:35,680 --> 00:32:38,160 Speaker 1: it does is it builds a sugar. They turn light, 623 00:32:38,320 --> 00:32:41,680 Speaker 1: not into electricity, because plants aren't interested in electricity. They 624 00:32:41,680 --> 00:32:45,040 Speaker 1: don't run air conditioning or sit on their phones all day. Right. 625 00:32:45,280 --> 00:32:48,440 Speaker 1: It basically turns light into plant food, which is these 626 00:32:48,480 --> 00:32:52,680 Speaker 1: complex carbohydrates, these carbons and hydrogens and oxygen's all built 627 00:32:52,720 --> 00:32:54,720 Speaker 1: together into things that are fiber or what we would 628 00:32:54,800 --> 00:32:57,600 Speaker 1: call sugar. They do it through chemistry. Like you know, 629 00:32:57,680 --> 00:32:59,800 Speaker 1: they have the ingredients, they're sort of on the leaf, 630 00:33:00,000 --> 00:33:03,800 Speaker 1: and then the sunlight triggers a reaction or triggers like 631 00:33:03,880 --> 00:33:07,960 Speaker 1: a molecules kind of coming together. Yeah, exactly. Chemistry is 632 00:33:08,000 --> 00:33:11,600 Speaker 1: all about energy flows, right, So you can store energy 633 00:33:11,680 --> 00:33:14,760 Speaker 1: in chemical bonds. You can build something that has energy 634 00:33:14,800 --> 00:33:16,600 Speaker 1: inside of it, but then you need to put the 635 00:33:16,720 --> 00:33:19,200 Speaker 1: energy in. Right. You can't just have the ingredients. They're 636 00:33:19,240 --> 00:33:21,640 Speaker 1: sort of like baking a cake. You can just mix 637 00:33:21,680 --> 00:33:24,080 Speaker 1: the ingredients. You need to supply the heat. And so 638 00:33:24,160 --> 00:33:27,320 Speaker 1: in order to make these sugars, these sugars which store energy, 639 00:33:27,680 --> 00:33:30,000 Speaker 1: you need to bring the wrong ingredients together, which is 640 00:33:30,040 --> 00:33:32,880 Speaker 1: carbon dioxide and water, and then you need to apply 641 00:33:33,000 --> 00:33:35,280 Speaker 1: the energy. And that's where the photon comes in. As 642 00:33:35,400 --> 00:33:38,400 Speaker 1: the photon comes in and chemistry happens, and then you 643 00:33:38,440 --> 00:33:41,040 Speaker 1: get out, You get sugar, and you get oxygen as 644 00:33:41,040 --> 00:33:44,960 Speaker 1: a byproduct, which is wonderful for all of us oxygen breathers, yeah, 645 00:33:45,000 --> 00:33:48,280 Speaker 1: and all of those salad eaters. Yeah, and for the 646 00:33:48,280 --> 00:33:53,080 Speaker 1: plant specifically. It's basically turned the energy into plant food. Right. 647 00:33:53,120 --> 00:33:56,000 Speaker 1: So we want to generate electricity and plants. What they 648 00:33:56,000 --> 00:33:57,920 Speaker 1: want to do is they want to generate these sugars. 649 00:33:58,200 --> 00:33:59,920 Speaker 1: And really the answer to the question of you know 650 00:34:00,240 --> 00:34:02,560 Speaker 1: why is photosed in this is less efficient than solar 651 00:34:02,560 --> 00:34:05,800 Speaker 1: power is really that they're doing different things. Plants have 652 00:34:05,840 --> 00:34:09,560 Speaker 1: optimized turning photons into plant food, into this fuel which 653 00:34:09,560 --> 00:34:12,440 Speaker 1: they can store and then very easily use later on, 654 00:34:12,880 --> 00:34:15,839 Speaker 1: whereas we've optimized for creating these electrons which we can 655 00:34:15,880 --> 00:34:19,600 Speaker 1: either use immediately or try to funnel into batteries. It's 656 00:34:19,600 --> 00:34:22,719 Speaker 1: almost like they've invented the battery and the panel at 657 00:34:22,760 --> 00:34:26,000 Speaker 1: the same time. Yeah, it's really pretty impressive technology. Right. 658 00:34:26,320 --> 00:34:28,960 Speaker 1: This plant fuel is a great way to store energy, 659 00:34:29,320 --> 00:34:31,359 Speaker 1: and so it's a really nice thing for them because 660 00:34:31,400 --> 00:34:33,120 Speaker 1: they can use it whenever they need it. They don't 661 00:34:33,120 --> 00:34:35,400 Speaker 1: have to worry about creating the battery. Right And if 662 00:34:35,440 --> 00:34:38,640 Speaker 1: I get takes carbon diotside from the era, yeah exactly 663 00:34:38,680 --> 00:34:44,120 Speaker 1: and produces oxygen and delicious vegetables and delicious vegetables exactly. 664 00:34:44,239 --> 00:34:46,680 Speaker 1: And you know it also it captures a different fraction 665 00:34:46,880 --> 00:34:49,919 Speaker 1: of the solar energy. Like photobole take cells, the ones 666 00:34:49,920 --> 00:34:52,440 Speaker 1: that we build, they can capture energy that's out of 667 00:34:52,440 --> 00:34:54,200 Speaker 1: the visible spectrum. You don't have to be able to 668 00:34:54,200 --> 00:34:56,719 Speaker 1: see the photon for your solar panel to be able 669 00:34:56,760 --> 00:34:59,759 Speaker 1: to slurp it up and turn it into electricity. You 670 00:34:59,760 --> 00:35:02,440 Speaker 1: can also captured the energy of photons that have a 671 00:35:02,440 --> 00:35:05,960 Speaker 1: wavelength it's too long they're in the infrared, or photons 672 00:35:05,960 --> 00:35:08,040 Speaker 1: that have a wavelength it's too short there in the 673 00:35:08,120 --> 00:35:11,399 Speaker 1: ultra violet. Your photovolt take cells made from silicon can 674 00:35:11,440 --> 00:35:15,120 Speaker 1: slurk that up. Plants are mostly sensitive to the visible spectrum, 675 00:35:15,239 --> 00:35:17,080 Speaker 1: so they get sort of a smaller slice of all 676 00:35:17,120 --> 00:35:19,760 Speaker 1: the light that comes in. But I think solar panels 677 00:35:19,880 --> 00:35:23,280 Speaker 1: also use a photo will take effect a little bit similar. 678 00:35:23,360 --> 00:35:27,000 Speaker 1: I mean, they're optimized for certain wavelengths, right, Yeah, I 679 00:35:27,000 --> 00:35:30,120 Speaker 1: mean we certainly are optimized for the wavelengths that come 680 00:35:30,160 --> 00:35:32,759 Speaker 1: from the sun. Right. They've chosen a material that can 681 00:35:32,840 --> 00:35:35,440 Speaker 1: absorb it, and you're right, this is quantum mechanical, and 682 00:35:35,480 --> 00:35:38,440 Speaker 1: so you can't absorb just any photon that comes in. 683 00:35:38,520 --> 00:35:40,440 Speaker 1: It has to be a good match for the material, 684 00:35:40,560 --> 00:35:43,879 Speaker 1: because every material has certain wavelength of light it can 685 00:35:43,960 --> 00:35:47,200 Speaker 1: absorb and other wavelengths it's transparent to. And so one 686 00:35:47,200 --> 00:35:49,520 Speaker 1: of the reasons silicon has chosen it's not just because 687 00:35:49,560 --> 00:35:52,600 Speaker 1: it's a semiconductor, but because they can absorb light in 688 00:35:52,640 --> 00:35:56,560 Speaker 1: the wavelength that's hitting the earth. So plants aren't as efficient, 689 00:35:56,719 --> 00:35:58,840 Speaker 1: but they're pretty good at other things, right, Like a 690 00:35:58,960 --> 00:36:01,080 Speaker 1: plant you know, need to hose it down when it 691 00:36:01,440 --> 00:36:04,920 Speaker 1: gets too dusty. That's right. Plants are a much nicer 692 00:36:04,960 --> 00:36:07,760 Speaker 1: option compared to solar panels in some way because, for example, 693 00:36:07,960 --> 00:36:10,600 Speaker 1: they build themselves. Right if you could just sprinkle like 694 00:36:10,719 --> 00:36:13,680 Speaker 1: solar panel seeds on your roof and they like sprouted 695 00:36:13,760 --> 00:36:16,800 Speaker 1: up and created working solar panels, that would be pretty awesome. 696 00:36:16,840 --> 00:36:19,160 Speaker 1: That would be pretty awesome. Yeah, that sounds like crazy 697 00:36:19,160 --> 00:36:22,120 Speaker 1: science fiction, right, but that's basically what plants can do. 698 00:36:22,160 --> 00:36:24,919 Speaker 1: They self assemble from a seed. Ma. You ever look 699 00:36:24,920 --> 00:36:27,640 Speaker 1: at it like a huge tree and wonder like where 700 00:36:27,640 --> 00:36:30,600 Speaker 1: did all this stuff from that tree come from? Well, 701 00:36:30,600 --> 00:36:33,399 Speaker 1: that tree has basically built itself out of the air. 702 00:36:33,800 --> 00:36:36,080 Speaker 1: It has pulled the carbon out of the air to 703 00:36:36,160 --> 00:36:40,960 Speaker 1: construct itself. That's pretty awesome engineering. You know, without any supervision, 704 00:36:41,000 --> 00:36:45,080 Speaker 1: no project management, no Excel spreadsheets, you know, no invoices, 705 00:36:45,280 --> 00:36:48,360 Speaker 1: no meetings. It just did it. That's the most attractive 706 00:36:48,400 --> 00:36:50,960 Speaker 1: part to you right now, Like no zoom meetings were 707 00:36:51,000 --> 00:36:55,440 Speaker 1: required to make this tree. That's that's the apex of 708 00:36:55,440 --> 00:36:58,759 Speaker 1: of cleverness and a cheatment there, yeah, exactly. And and 709 00:36:58,920 --> 00:37:01,920 Speaker 1: on top of that, they fix themselves. You know, if 710 00:37:02,000 --> 00:37:04,400 Speaker 1: you shadow your solar panel, you can't come back the 711 00:37:04,400 --> 00:37:07,200 Speaker 1: next day and see it started to heal. But if 712 00:37:07,239 --> 00:37:09,400 Speaker 1: a leaf falls off your plant, it'll just grow a 713 00:37:09,440 --> 00:37:12,520 Speaker 1: new one, you know, it'll just fix itself. So they're 714 00:37:12,520 --> 00:37:15,880 Speaker 1: really pretty awesome, and they can be grown basically anywhere 715 00:37:16,040 --> 00:37:18,000 Speaker 1: using the materials readily at hand. You don't have to 716 00:37:18,080 --> 00:37:20,600 Speaker 1: mind this delicate material out of the crust of the earth. 717 00:37:20,960 --> 00:37:22,440 Speaker 1: So I've got a lot of good things to say 718 00:37:22,440 --> 00:37:26,640 Speaker 1: about plants. And even though technically their energy transmission rate 719 00:37:26,760 --> 00:37:31,239 Speaker 1: is less efficient than photovoltaic panels, they're pretty awesome. Yeah. Now, 720 00:37:31,280 --> 00:37:34,640 Speaker 1: for sure, plants are amazing, But they can't power my 721 00:37:34,880 --> 00:37:38,319 Speaker 1: computer or our podcast recorder here, No, not directly. But 722 00:37:38,400 --> 00:37:41,880 Speaker 1: you know, there are folks who are working on electric leaves. 723 00:37:42,080 --> 00:37:44,799 Speaker 1: What what do you mean? These are mechanical devices or 724 00:37:44,800 --> 00:37:48,880 Speaker 1: electrical devices that are trying to replicate photosynthesis instead of 725 00:37:49,239 --> 00:37:53,640 Speaker 1: replicating you know, photovoltaic process. So you have the stuff 726 00:37:53,680 --> 00:37:58,120 Speaker 1: inside this device, basically water and carbon dioxide, and you 727 00:37:58,280 --> 00:38:02,759 Speaker 1: want to replicate photosynthesis to produce sugar and oxygen. So 728 00:38:02,920 --> 00:38:06,880 Speaker 1: electric leaf is different from a photovoltaic cell, right, So 729 00:38:07,040 --> 00:38:09,719 Speaker 1: it will produce sugar as an output. Like you can 730 00:38:09,760 --> 00:38:12,600 Speaker 1: have a sugar factory on your roof. You feed in 731 00:38:12,680 --> 00:38:16,799 Speaker 1: carbon dioxide and water and sunlight, and yes, it will 732 00:38:16,840 --> 00:38:20,080 Speaker 1: give you sugar and oxygen. So there's a whole group 733 00:38:20,160 --> 00:38:23,160 Speaker 1: of folks working on these artificial leaves instead of working 734 00:38:23,160 --> 00:38:25,799 Speaker 1: on photobo take cells. Interesting, so you can put it 735 00:38:25,840 --> 00:38:28,200 Speaker 1: in your cold coffee because you don't have any electricity 736 00:38:28,200 --> 00:38:32,040 Speaker 1: to heat it up. Yeah, but you know, artificial leaves 737 00:38:32,239 --> 00:38:35,040 Speaker 1: still do not grow themselves or fix themselves, and there 738 00:38:35,080 --> 00:38:37,759 Speaker 1: are a lot more expensive than a seed. So it's 739 00:38:37,760 --> 00:38:41,600 Speaker 1: a tough engineering challenge to beat nature at its own game. Yeah. Well, 740 00:38:41,600 --> 00:38:44,480 Speaker 1: what if Daniel, you build like a factory with AI 741 00:38:45,719 --> 00:38:49,719 Speaker 1: that makes its own solar panel to power itself. That 742 00:38:49,719 --> 00:38:53,399 Speaker 1: would be sort of like making a self growing solar panel. Yeah. 743 00:38:53,440 --> 00:38:55,719 Speaker 1: If you design robots that could build solar panels and 744 00:38:55,800 --> 00:38:58,680 Speaker 1: manage them and fix them, then yeah, that would be 745 00:38:58,680 --> 00:39:02,280 Speaker 1: pretty awesome. That's kind of what a plant is, isn't it. 746 00:39:02,280 --> 00:39:04,600 Speaker 1: It's like a little robot. I mean, it's just following 747 00:39:04,600 --> 00:39:06,520 Speaker 1: the instructions in the DNA. It's just kind of like 748 00:39:06,520 --> 00:39:09,520 Speaker 1: a little robot that's following its own instructions. Yeah, it's 749 00:39:09,560 --> 00:39:12,040 Speaker 1: a little organic, evolved robot. But then I guess so 750 00:39:12,200 --> 00:39:15,399 Speaker 1: are we, right until your AI goes crazy and then 751 00:39:15,440 --> 00:39:18,560 Speaker 1: just covers the whole planet with solar panels, right, which 752 00:39:18,600 --> 00:39:22,000 Speaker 1: would be give us a lot of energy there you go, 753 00:39:22,920 --> 00:39:25,560 Speaker 1: but to be nobody to use it, right, like sorry, 754 00:39:25,680 --> 00:39:28,000 Speaker 1: or have to knock down your house to build solar panels. 755 00:39:28,120 --> 00:39:31,040 Speaker 1: Those are my instructions. Well, I can live under the panel. 756 00:39:31,920 --> 00:39:34,839 Speaker 1: I'm just saying. You know, I'm imagining this science fiction novel, 757 00:39:34,840 --> 00:39:37,000 Speaker 1: a future dystopia where we all live in the darkness, 758 00:39:37,239 --> 00:39:39,839 Speaker 1: but we have a lot of energy from the solar panels. Yeah, 759 00:39:39,840 --> 00:39:42,759 Speaker 1: well you can build windows. I mean, come on, they 760 00:39:42,760 --> 00:39:46,120 Speaker 1: can spare a few percentage of the square footage there 761 00:39:46,160 --> 00:39:48,239 Speaker 1: and then the robot comes along and filled it in 762 00:39:48,239 --> 00:39:52,200 Speaker 1: with a solar panel. Alright, a little off topic here. 763 00:39:52,320 --> 00:39:57,399 Speaker 1: So solar panels, Yes, they take sunlight and converted to electricity, 764 00:39:57,440 --> 00:40:00,480 Speaker 1: and they do it through these silicon sir kids. But 765 00:40:00,560 --> 00:40:04,560 Speaker 1: you know, they take some infrastructure, but overall, the infrastructure 766 00:40:04,800 --> 00:40:07,080 Speaker 1: sort of worth it, right because it's clean energy, absolutely, 767 00:40:07,280 --> 00:40:10,200 Speaker 1: and the infrastructure can get cleaner and simpler and cheaper. 768 00:40:10,440 --> 00:40:12,919 Speaker 1: That's an engineering that's a technology barrier. It's not something 769 00:40:12,960 --> 00:40:15,920 Speaker 1: fundamental to the process, like with nuclear fission, which will 770 00:40:15,920 --> 00:40:19,439 Speaker 1: always produce some toxic waste, or with fossil fuels, which 771 00:40:19,440 --> 00:40:22,239 Speaker 1: will always release some sort of carbon. This at its 772 00:40:22,239 --> 00:40:25,040 Speaker 1: core is a really clean, cheap source of energy that's 773 00:40:25,040 --> 00:40:27,840 Speaker 1: already produced and being beamed to us from the facility 774 00:40:27,920 --> 00:40:31,120 Speaker 1: ninety million miles away. Yeah, and it's a guilt free 775 00:40:32,239 --> 00:40:34,040 Speaker 1: that's right. It's negative guilt. So you can turn on 776 00:40:34,080 --> 00:40:36,440 Speaker 1: your solo panel and have an extra box of cookies. 777 00:40:37,760 --> 00:40:40,359 Speaker 1: There you go, and the electric company will send you 778 00:40:40,400 --> 00:40:44,760 Speaker 1: a box of cookies every month or money, whichever you prefer. 779 00:40:44,920 --> 00:40:47,000 Speaker 1: All right, well, we hope you enjoyed that. Thanks for 780 00:40:47,080 --> 00:40:57,680 Speaker 1: joining us, see you next time. Thanks for listening, and 781 00:40:57,719 --> 00:41:00,440 Speaker 1: remember that Daniel and Jorge explain. The univer is a 782 00:41:00,520 --> 00:41:03,920 Speaker 1: production of I Heart Radio. Or more podcast from my 783 00:41:04,040 --> 00:41:07,640 Speaker 1: heart Radio. Visit the I Heart Radio app, Apple Podcasts, 784 00:41:07,760 --> 00:41:10,080 Speaker 1: or wherever you listen to your favorite shows.