1
00:00:00,080 --> 00:00:02,960
Speaker 1: If you love iPhone, you'll love Apple Card. It's the

2
00:00:03,040 --> 00:00:06,920
Speaker 1: credit card designed for iPhone. It gives you unlimited daily

3
00:00:07,040 --> 00:00:10,000
Speaker 1: cash back that can earn four point four zero percent

4
00:00:10,160 --> 00:00:12,960
Speaker 1: annual percentage yield. When you open a high Yield savings

5
00:00:13,000 --> 00:00:16,280
Speaker 1: account through Apple Card, apply for Applecard in the wallet

6
00:00:16,280 --> 00:00:19,520
Speaker 1: app subject to credit approval. Savings is available to Apple

7
00:00:19,560 --> 00:00:22,800
Speaker 1: Card owners subject to eligibility. Apple Card and Savings by

8
00:00:22,840 --> 00:00:26,120
Speaker 1: Goldman Sachs Bank USA, Salt Lake City Branch, Member FDIC

9
00:00:26,520 --> 00:00:29,280
Speaker 1: terms and more at applecard dot Com. When you pop

10
00:00:29,320 --> 00:00:31,240
Speaker 1: a piece of cheese into your mouth, you're probably not

11
00:00:31,360 --> 00:00:34,280
Speaker 1: thinking about the environmental impact. But the people in the

12
00:00:34,360 --> 00:00:37,680
Speaker 1: dairy industry are. That's why they're working hard every day

13
00:00:37,720 --> 00:00:40,760
Speaker 1: to find new ways to reduce waste, conserve natural resources,

14
00:00:40,800 --> 00:00:44,400
Speaker 1: and drive down greenhouse gas emissions. How is US Dairy

15
00:00:44,400 --> 00:00:48,520
Speaker 1: tackling greenhouse gases? Many farms use anaerobic digesters to turn

16
00:00:48,560 --> 00:00:53,080
Speaker 1: the methane from manure into renewable energy that can power farms, towns,

17
00:00:53,120 --> 00:00:57,240
Speaker 1: and electric cars. Visit us dairy dot COM's Last Sustainability

18
00:00:57,280 --> 00:00:58,000
Speaker 1: to learn more.

19
00:00:59,000 --> 00:00:59,160
Speaker 2: Hi.

20
00:00:59,280 --> 00:01:02,920
Speaker 3: I'm David Ego from the podcast Inner Cosmos, which recently

21
00:01:03,000 --> 00:01:05,760
Speaker 3: hit the number one science podcast in America. I mean

22
00:01:05,840 --> 00:01:09,520
Speaker 3: neuroscientists at Stanford, and I've spent my career exploring the

23
00:01:09,600 --> 00:01:11,560
Speaker 3: three pound universe in our heads.

24
00:01:11,920 --> 00:01:15,000
Speaker 2: Join me weekly to explore the relationship.

25
00:01:14,319 --> 00:01:17,280
Speaker 3: Between your brain and your life, because the more we

26
00:01:17,360 --> 00:01:20,280
Speaker 3: know about what's running under the hood, better we can

27
00:01:20,319 --> 00:01:24,000
Speaker 3: steer our lives. Listen to Inner Cosmos with David Eagleman

28
00:01:24,120 --> 00:01:27,360
Speaker 3: on the iHeartRadio app, Apple Podcasts or wherever you get

29
00:01:27,360 --> 00:01:28,280
Speaker 3: your podcasts.

30
00:01:37,160 --> 00:01:39,840
Speaker 2: Hey, Daniel, I have a question about Nobel prices.

31
00:01:39,920 --> 00:01:42,680
Speaker 1: Well, you know they aren't awarded until much later this year,

32
00:01:42,800 --> 00:01:44,800
Speaker 1: so don't stay up late and wait by your phone.

33
00:01:44,840 --> 00:01:47,400
Speaker 2: Oh really, they don't give one for a podcasts.

34
00:01:47,120 --> 00:01:49,320
Speaker 1: No, and they also don't give a banana prize.

35
00:01:49,440 --> 00:01:51,600
Speaker 2: Well, my question is about the physics Nobel price.

36
00:01:51,720 --> 00:01:53,720
Speaker 1: Well, I'm not staying up late and waiting by the

37
00:01:53,720 --> 00:01:54,360
Speaker 1: phone either.

38
00:01:54,480 --> 00:01:57,760
Speaker 2: Well, my question is whether it's given to some discovery

39
00:01:57,760 --> 00:02:00,880
Speaker 2: that is deep or a discovery that's you useful to humanity.

40
00:02:01,040 --> 00:02:02,640
Speaker 1: Why does it have to be one or the other.

41
00:02:02,760 --> 00:02:05,160
Speaker 1: Isn't deep knowledge also useful?

42
00:02:05,680 --> 00:02:08,120
Speaker 2: Have you found neutrinos to be useful to humanity?

43
00:02:08,240 --> 00:02:08,679
Speaker 4: Not yet?

44
00:02:08,800 --> 00:02:11,600
Speaker 1: Actually, I'm still waiting for aliens to teach us how

45
00:02:11,639 --> 00:02:13,480
Speaker 1: to use neutrinos to get a safe tan.

46
00:02:13,880 --> 00:02:17,840
Speaker 2: Yeah, don't wait by the phone for that. Sweden, call me, Jupiter,

47
00:02:17,960 --> 00:02:21,920
Speaker 2: call me what is that? If there are eighties and Jupiter,

48
00:02:22,160 --> 00:02:25,560
Speaker 2: I want the Jovian Nobel Prize for Best Podcast. Sidekick.

49
00:02:26,000 --> 00:02:27,240
Speaker 1: Wait, you're not the sidekick.

50
00:02:27,280 --> 00:02:44,320
Speaker 2: I'm decided what I am. Horehea, my cartoonist and the

51
00:02:44,360 --> 00:02:45,800
Speaker 2: creator of PhD.

52
00:02:45,400 --> 00:02:48,760
Speaker 1: Comments, Hi, I'm Daniel. I'm a particle physicist and until

53
00:02:48,800 --> 00:02:51,120
Speaker 1: a moment ago I thought I was the sidekick on

54
00:02:51,120 --> 00:02:52,560
Speaker 1: this podcast.

55
00:02:51,960 --> 00:02:55,400
Speaker 2: And so welcome to our podcast, the award winning science

56
00:02:55,400 --> 00:02:58,680
Speaker 2: and physics podcast called Daniel and Jorge Explain the Universe.

57
00:02:58,760 --> 00:03:00,160
Speaker 1: Remind me which award we.

58
00:03:00,639 --> 00:03:04,440
Speaker 2: Won, the award for having no awards yet.

59
00:03:05,160 --> 00:03:08,239
Speaker 1: The award for best podcast that features only two sidekicks.

60
00:03:08,440 --> 00:03:11,280
Speaker 2: We're sidekicking it here on our podcast. But yeah, it's

61
00:03:11,320 --> 00:03:14,840
Speaker 2: our podcast about physics and science and astronomy and the

62
00:03:14,960 --> 00:03:16,720
Speaker 2: universe and everything in between.

63
00:03:16,840 --> 00:03:19,720
Speaker 1: Our podcast in which we share with you the gorgeous,

64
00:03:19,760 --> 00:03:22,320
Speaker 1: amazing mysteries of the universe. We take you on a

65
00:03:22,360 --> 00:03:25,040
Speaker 1: mental tour to all the crazy stuff that's out there,

66
00:03:25,200 --> 00:03:28,080
Speaker 1: that's in here, the tiny stuff, the huge stuff, and

67
00:03:28,120 --> 00:03:30,080
Speaker 1: we explain it all to you in a way that

68
00:03:30,120 --> 00:03:32,000
Speaker 1: we hope also makes you chuckle.

69
00:03:31,800 --> 00:03:33,560
Speaker 2: Yeah, because you know, we hope to open up your

70
00:03:33,639 --> 00:03:36,760
Speaker 2: mind to the amazing and incredible things that are happening

71
00:03:36,840 --> 00:03:38,920
Speaker 2: right now in the far reaches of the universe and

72
00:03:39,000 --> 00:03:41,520
Speaker 2: the far corners of the Solar System. But we also

73
00:03:41,600 --> 00:03:43,600
Speaker 2: kind of want to open your eyes to see you

74
00:03:44,040 --> 00:03:46,880
Speaker 2: all of the amazing science that's happening all around you

75
00:03:46,960 --> 00:03:47,240
Speaker 2: right now.

76
00:03:47,280 --> 00:03:49,560
Speaker 1: Because one of the most amazing things about physics is

77
00:03:49,560 --> 00:03:53,440
Speaker 1: that the same laws of physics operate on black holes

78
00:03:53,520 --> 00:03:57,400
Speaker 1: and nebula and neutron stars and you and me and

79
00:03:57,440 --> 00:03:59,560
Speaker 1: everything in our world. This is one of the most

80
00:03:59,720 --> 00:04:03,080
Speaker 1: earth shattering revelations of physics in the last few hundred years,

81
00:04:03,400 --> 00:04:05,440
Speaker 1: that the physics of the cosmos and the physics of

82
00:04:05,440 --> 00:04:08,600
Speaker 1: the everyday are the same physics, which means that we

83
00:04:08,640 --> 00:04:11,200
Speaker 1: can discover the secrets of the universe just by doing

84
00:04:11,240 --> 00:04:12,800
Speaker 1: experiments in our laboratory.

85
00:04:12,840 --> 00:04:14,600
Speaker 2: Yeah, it's all the same. Being trapped in a black

86
00:04:14,640 --> 00:04:18,480
Speaker 2: hole or being trapped in your apartment for an indefinite

87
00:04:18,480 --> 00:04:20,320
Speaker 2: amount of time. It's all the same. You can do

88
00:04:20,360 --> 00:04:21,120
Speaker 2: physics anywhere.

89
00:04:21,160 --> 00:04:24,200
Speaker 1: They're crushing in different ways. But it also means that

90
00:04:24,240 --> 00:04:28,000
Speaker 1: we can look around us and find amazing crazy stuff

91
00:04:28,000 --> 00:04:31,120
Speaker 1: that reveals secrets of the universe. Like quantum mechanics was

92
00:04:31,120 --> 00:04:33,960
Speaker 1: not discovered inside a black hole. It was found just

93
00:04:34,000 --> 00:04:36,520
Speaker 1: by shooting photons at weird kinds of metal.

94
00:04:36,560 --> 00:04:38,720
Speaker 2: And so today we'll be talking about an invention. Dad,

95
00:04:39,160 --> 00:04:41,760
Speaker 2: I would argue, maybe is one of the most commonplace

96
00:04:41,960 --> 00:04:46,880
Speaker 2: or most prevalent technologies out there in human technology humankind.

97
00:04:46,920 --> 00:04:50,039
Speaker 1: Right, are you talking about the wheel fire?

98
00:04:50,120 --> 00:04:52,600
Speaker 2: The hoverboard? I was hoping for the hoverboard. Hasn't that

99
00:04:52,600 --> 00:04:54,160
Speaker 2: that happened yet, Daniel.

100
00:04:55,320 --> 00:04:57,920
Speaker 1: No, it is not, but I'm sure somebody accidentally ordered

101
00:04:57,920 --> 00:04:59,960
Speaker 1: a hoverboard on Amazon got something else.

102
00:05:00,440 --> 00:05:03,359
Speaker 2: Well, it's a technology that I think basically almost every

103
00:05:03,480 --> 00:05:06,240
Speaker 2: human looks at on a daily basis, maybe even an

104
00:05:06,240 --> 00:05:07,040
Speaker 2: hourly basis.

105
00:05:07,040 --> 00:05:08,240
Speaker 1: Now you have me at the edge of my seat.

106
00:05:08,240 --> 00:05:09,360
Speaker 1: What are we talking about today?

107
00:05:09,600 --> 00:05:11,640
Speaker 2: What do you mean? I thought you knew what we

108
00:05:11,640 --> 00:05:12,520
Speaker 2: were talking about today.

109
00:05:12,960 --> 00:05:15,120
Speaker 1: I'm the sidekick here. Remember you're in charge.

110
00:05:15,120 --> 00:05:17,640
Speaker 2: Oh, I see, I see what's on our phones? You know,

111
00:05:17,680 --> 00:05:19,840
Speaker 2: everyone looks at their phone every couple of minutes. It's

112
00:05:19,880 --> 00:05:22,480
Speaker 2: on our computer screens, on our televisions, which I'm sure

113
00:05:22,520 --> 00:05:24,640
Speaker 2: a lot of people are watching a lot of these days,

114
00:05:24,680 --> 00:05:26,520
Speaker 2: so it illuminates everything.

115
00:05:26,240 --> 00:05:29,839
Speaker 1: You're talking about my sheer genius, right, my brilliance.

116
00:05:29,400 --> 00:05:33,440
Speaker 2: Talk about Netflix. I'm just kidding. Well, it's I just

117
00:05:33,440 --> 00:05:36,120
Speaker 2: figured out it's on the title of our podcast. So

118
00:05:36,400 --> 00:05:38,680
Speaker 2: I'm guessing that people will already know by the time

119
00:05:38,680 --> 00:05:39,240
Speaker 2: they click in.

120
00:05:39,320 --> 00:05:41,320
Speaker 1: That's right. I hope they haven't been misled.

121
00:05:42,279 --> 00:05:44,240
Speaker 2: That's right. We'll lead them to the light.

122
00:05:44,480 --> 00:05:45,000
Speaker 1: That's right.

123
00:05:45,040 --> 00:05:52,160
Speaker 2: So to that the podcast, we'll be talking about LEDs.

124
00:05:52,440 --> 00:05:54,640
Speaker 2: How do LEDs work, what are the physics of it?

125
00:05:54,720 --> 00:05:58,280
Speaker 2: And why did somebody win a Nobel Prize for inventing

126
00:05:58,520 --> 00:05:59,840
Speaker 2: a particular color of it?

127
00:06:00,040 --> 00:06:03,000
Speaker 1: That's right. We have physic Nobel Prizes for things like

128
00:06:03,480 --> 00:06:07,680
Speaker 1: understanding quantum mechanics and figuring out what the basic particles are,

129
00:06:08,160 --> 00:06:11,240
Speaker 1: or for you know, an observation of gravitational waves. Things

130
00:06:11,240 --> 00:06:14,560
Speaker 1: really reveal the fundamental fabric and nature of the universe.

131
00:06:14,600 --> 00:06:17,760
Speaker 1: And then we have Nobel Prizes for the invention of

132
00:06:17,839 --> 00:06:19,280
Speaker 1: the blue led.

133
00:06:19,240 --> 00:06:23,120
Speaker 2: Blue led, not the red led. That one did not win. No,

134
00:06:23,200 --> 00:06:25,159
Speaker 2: it was blued Nobel's favorite color.

135
00:06:26,040 --> 00:06:28,719
Speaker 1: Not at all, not at all. And so today we

136
00:06:28,760 --> 00:06:31,200
Speaker 1: wanted to dive into, like what are the physics of

137
00:06:31,320 --> 00:06:34,240
Speaker 1: LED's Is it really worth a Nobel Prize? What are

138
00:06:34,240 --> 00:06:36,720
Speaker 1: the sort of obstacles that they had to leap over

139
00:06:37,080 --> 00:06:39,640
Speaker 1: in order to make this thing work? And what physics

140
00:06:39,640 --> 00:06:41,320
Speaker 1: did they have to solve along the way. What does

141
00:06:41,360 --> 00:06:44,120
Speaker 1: it reveal about the nature of our universe that we

142
00:06:44,160 --> 00:06:46,119
Speaker 1: can now make LED's globe blue?

143
00:06:46,240 --> 00:06:48,000
Speaker 2: So what do you think about my idea that it's

144
00:06:48,040 --> 00:06:50,159
Speaker 2: maybe one of the most prevailing technologies out there?

145
00:06:50,240 --> 00:06:52,440
Speaker 1: You mean lights in general, or LED.

146
00:06:52,320 --> 00:06:56,480
Speaker 2: Specifically LED specifically, you know, because they're basically in every phone,

147
00:06:56,520 --> 00:06:59,040
Speaker 2: and there's billions of phones out there, and it's on

148
00:06:59,080 --> 00:07:02,320
Speaker 2: every computer screen, know, in TV screen, most of TV

149
00:07:02,400 --> 00:07:04,240
Speaker 2: screens have them. I would say it's up there along

150
00:07:04,279 --> 00:07:08,200
Speaker 2: with a concrete and toilet paper as the current most

151
00:07:08,240 --> 00:07:09,200
Speaker 2: important technology.

152
00:07:09,480 --> 00:07:12,000
Speaker 1: Yeah, you know, if people have been stockpiling LEDs ever

153
00:07:12,040 --> 00:07:14,280
Speaker 1: since the coronavirus came out, you know, just in case

154
00:07:14,400 --> 00:07:15,080
Speaker 1: they ran out.

155
00:07:15,400 --> 00:07:17,440
Speaker 2: Yeah, you know, just in case we run out of lights.

156
00:07:17,440 --> 00:07:19,600
Speaker 1: I think you're right, just had a really big impact

157
00:07:19,640 --> 00:07:22,120
Speaker 1: on everyday life. You see them in screens, you see

158
00:07:22,120 --> 00:07:24,440
Speaker 1: them in lights, you see them on trucks, you see

159
00:07:24,440 --> 00:07:25,200
Speaker 1: them everywhere. Now.

160
00:07:25,280 --> 00:07:27,720
Speaker 2: Yeah, Yeah, so it's a pretty important technology that's all

161
00:07:27,760 --> 00:07:30,480
Speaker 2: around us, that is hitting our eyeballs all of the time.

162
00:07:30,960 --> 00:07:32,840
Speaker 2: But as usually, we were wondering how many people out

163
00:07:32,840 --> 00:07:35,800
Speaker 2: there know how LED's work or what it even stands

164
00:07:35,800 --> 00:07:38,720
Speaker 2: for LED. So as usual, Daniel went out into the

165
00:07:38,720 --> 00:07:41,880
Speaker 2: world and ask people if they do how an LED works.

166
00:07:41,920 --> 00:07:46,160
Speaker 1: That's right, and these questions actually pre date the coronavirus pandemic,

167
00:07:46,200 --> 00:07:50,240
Speaker 1: and so these are historical records of in person interviews

168
00:07:50,280 --> 00:07:51,600
Speaker 1: back when that was still possible.

169
00:07:51,680 --> 00:07:54,080
Speaker 2: Oh really, Oh, this is an actual on the street.

170
00:07:54,280 --> 00:07:56,640
Speaker 1: These are from the archive. We haven't had a chance

171
00:07:56,640 --> 00:07:58,280
Speaker 1: to pull this episode out yet.

172
00:07:58,320 --> 00:08:00,960
Speaker 2: I see. Do you think people's opinions about LEDs would

173
00:08:01,040 --> 00:08:01,920
Speaker 2: have changed by now?

174
00:08:02,120 --> 00:08:05,000
Speaker 1: While people are spending more time inside under the lights

175
00:08:05,000 --> 00:08:08,760
Speaker 1: looking at instead of a deeper relationship with LED's.

176
00:08:08,480 --> 00:08:11,080
Speaker 2: Name, maybe hypnotizes a little bit more since.

177
00:08:11,200 --> 00:08:13,440
Speaker 1: Yeah, well you know, people are looking at more screens

178
00:08:13,480 --> 00:08:15,840
Speaker 1: and so they have a hopefully more affection for LED.

179
00:08:16,000 --> 00:08:17,880
Speaker 2: Yeah. So think about it for a second. If someone

180
00:08:17,920 --> 00:08:19,840
Speaker 2: asks you how an LED works, would you know what

181
00:08:19,960 --> 00:08:21,840
Speaker 2: to answer? Here's what people had to say.

182
00:08:21,960 --> 00:08:24,040
Speaker 1: No, but I just know it's a better light.

183
00:08:24,320 --> 00:08:26,080
Speaker 2: Part of me really wants you to just say electricity,

184
00:08:26,240 --> 00:08:29,520
Speaker 2: But isn't it. No, that's fluorescence. Never mind, I was

185
00:08:29,560 --> 00:08:32,360
Speaker 2: going to say gas, but that's just fluorescence the light.

186
00:08:34,760 --> 00:08:39,040
Speaker 3: Yeah, I'm going to assume it's due to a resonance

187
00:08:39,080 --> 00:08:41,880
Speaker 3: frequency within within the LED.

188
00:08:42,320 --> 00:08:43,400
Speaker 2: I'm not sure.

189
00:08:43,480 --> 00:08:49,920
Speaker 5: Essentially, it's just a PM junction. One side has holes

190
00:08:50,080 --> 00:08:54,760
Speaker 5: inside has an accessible electrons, and especially transitions in the

191
00:08:54,800 --> 00:08:57,520
Speaker 5: state of the PM junction really slight.

192
00:08:57,720 --> 00:09:04,320
Speaker 4: So yeah, oh, honestly, I don't know.

193
00:09:05,800 --> 00:09:06,840
Speaker 2: I literally don't know.

194
00:09:07,720 --> 00:09:13,560
Speaker 4: Kind of yeah, yeah, I know excited Adams, but I

195
00:09:13,640 --> 00:09:18,600
Speaker 4: forgot like which Adam like maybe alien They excited to

196
00:09:19,320 --> 00:09:26,000
Speaker 4: a higher state energy state and where he falls generates energy.

197
00:09:26,160 --> 00:09:27,600
Speaker 4: But yeah, that's.

198
00:09:27,480 --> 00:09:28,920
Speaker 1: Kind of isn't that Fluorescence?

199
00:09:29,920 --> 00:09:33,720
Speaker 4: No similar, but fluorescence is like much weaker energy.

200
00:09:34,040 --> 00:09:35,320
Speaker 1: So what do you think of these responses?

201
00:09:35,360 --> 00:09:37,840
Speaker 2: Pretty good? I feel like they fall in love with

202
00:09:38,080 --> 00:09:40,240
Speaker 2: how I think about LEDs, which is that I don't

203
00:09:40,240 --> 00:09:41,120
Speaker 2: know much about him.

204
00:09:41,200 --> 00:09:44,000
Speaker 1: Yeah, I was a little surprised. Some people had no idea.

205
00:09:44,120 --> 00:09:46,720
Speaker 1: Some people thought they understood it, but we're actually talking

206
00:09:46,720 --> 00:09:50,240
Speaker 1: about a completely different type of light generation that's fluorescence.

207
00:09:50,880 --> 00:09:52,679
Speaker 2: People got him confused with fluorescent, Like.

208
00:09:52,720 --> 00:09:55,320
Speaker 1: Yeah, yeah, it turns out there's lots of different ways

209
00:09:55,360 --> 00:09:57,200
Speaker 1: to make lights. You know, you have incandescent light, we

210
00:09:57,240 --> 00:09:59,320
Speaker 1: have fluorescent lights, and then we have LED lights, and

211
00:09:59,559 --> 00:10:02,160
Speaker 1: they all bread on really different physical principles.

212
00:10:02,760 --> 00:10:05,800
Speaker 2: Yeah, maybe people have got them confused because I feel

213
00:10:05,800 --> 00:10:08,439
Speaker 2: like fluorescent lights, I know, they've been around for a

214
00:10:08,480 --> 00:10:10,880
Speaker 2: long time, you know, like neon signs and things like that,

215
00:10:10,960 --> 00:10:13,080
Speaker 2: and fluorescent bulbs, but they sort of made it into

216
00:10:13,120 --> 00:10:16,959
Speaker 2: people's homes more recently, but then right away LED sort

217
00:10:17,000 --> 00:10:19,000
Speaker 2: of came about and then totally replaced them.

218
00:10:19,080 --> 00:10:19,280
Speaker 4: Yeah.

219
00:10:19,320 --> 00:10:21,680
Speaker 1: Well, fluorescent lights have been around for quite a long time,

220
00:10:21,960 --> 00:10:23,880
Speaker 1: but yeah, they didn't make it into people's homes until

221
00:10:23,920 --> 00:10:25,479
Speaker 1: recently with the compact fluorescence.

222
00:10:25,520 --> 00:10:25,720
Speaker 2: Yeah.

223
00:10:25,760 --> 00:10:28,880
Speaker 1: But there's actually sort of a fascinating legal drama about

224
00:10:28,880 --> 00:10:32,480
Speaker 1: fluorescent lights because they were first developed pretty soon after

225
00:10:32,520 --> 00:10:35,320
Speaker 1: incandescent lights, but then General Electric bought up all the

226
00:10:35,360 --> 00:10:38,840
Speaker 1: patents and prevented anybody from developing them or using them,

227
00:10:39,120 --> 00:10:42,080
Speaker 1: and basically kept fluorescent lights out of the market for

228
00:10:42,200 --> 00:10:46,160
Speaker 1: decades just because they also owned the patents for incandescent lights.

229
00:10:46,400 --> 00:10:48,720
Speaker 1: So it's sort of a legal political drama that we

230
00:10:48,720 --> 00:10:49,960
Speaker 1: probably won't even get into today.

231
00:10:49,960 --> 00:10:52,760
Speaker 2: They're like fluorescence that works with gas, it's not electric.

232
00:10:52,840 --> 00:10:55,360
Speaker 2: It's on brand with us so we'll just sit in it.

233
00:10:55,480 --> 00:10:56,880
Speaker 1: Yeah, they just sort of bought it up and sat

234
00:10:56,880 --> 00:10:59,400
Speaker 1: on it as a dangerous technology that they thought would

235
00:10:59,400 --> 00:11:01,079
Speaker 1: sort of danger their business.

236
00:11:01,360 --> 00:11:05,080
Speaker 2: Well, let's get into how LEDs work, but first let's

237
00:11:05,080 --> 00:11:07,080
Speaker 2: maybe talk about how some of the other lights that

238
00:11:07,080 --> 00:11:09,720
Speaker 2: people are familiar with work. So take us back, Daniel,

239
00:11:09,960 --> 00:11:11,040
Speaker 2: how does the torch work?

240
00:11:12,480 --> 00:11:14,920
Speaker 1: You know, that's a really awesome question, actually, like what

241
00:11:15,080 --> 00:11:17,199
Speaker 1: is fire and how does it work? And I want

242
00:11:17,200 --> 00:11:19,680
Speaker 1: to do a whole podcast episode on what is fire

243
00:11:19,800 --> 00:11:23,080
Speaker 1: and what is the thing you're seeing that's glowing and cool?

244
00:11:23,120 --> 00:11:25,800
Speaker 1: And remember that's it's going to be totally lit. We're

245
00:11:25,840 --> 00:11:27,760
Speaker 1: going to brighten your life with that one. And remember

246
00:11:27,760 --> 00:11:30,160
Speaker 1: on our live stream somebody asked about that whether fire

247
00:11:30,240 --> 00:11:33,079
Speaker 1: can have a shadow, which is a totally awesome question.

248
00:11:33,360 --> 00:11:35,120
Speaker 1: But I think the first light that we should talk

249
00:11:35,160 --> 00:11:37,760
Speaker 1: about is incandescent lights. And these are the ones that

250
00:11:37,880 --> 00:11:40,240
Speaker 1: Edison invented, you know, the ones that people have had

251
00:11:40,240 --> 00:11:43,319
Speaker 1: in their homes until very recently. It has a little

252
00:11:43,440 --> 00:11:46,720
Speaker 1: filament in it that glows and eventually it breaks.

253
00:11:46,920 --> 00:11:47,120
Speaker 6: Right.

254
00:11:47,400 --> 00:11:49,280
Speaker 2: Yeah, Basically what people think of when they think of

255
00:11:49,280 --> 00:11:51,240
Speaker 2: a light bulb, like a round thing with a little

256
00:11:51,280 --> 00:11:52,200
Speaker 2: wire through the middle.

257
00:11:52,280 --> 00:11:54,960
Speaker 1: Yeah, that's your classic light bulb. And all the technologies

258
00:11:54,960 --> 00:11:57,080
Speaker 1: that we're going to talk about today operate under the

259
00:11:57,120 --> 00:12:01,479
Speaker 1: same essential goal, which is turn electricity into photons.

260
00:12:01,679 --> 00:12:03,440
Speaker 2: Do you think when Edison had the idea for the

261
00:12:03,520 --> 00:12:05,319
Speaker 2: light bulb, do you think he had a light bulb

262
00:12:05,320 --> 00:12:07,920
Speaker 2: over his head? Like, was that the only time in

263
00:12:08,040 --> 00:12:10,959
Speaker 2: history when like somebody was actually thinking of a light

264
00:12:10,960 --> 00:12:11,920
Speaker 2: bulb when they had an idea.

265
00:12:12,000 --> 00:12:13,520
Speaker 1: Yeah, that's where it comes from, right, that was the

266
00:12:13,520 --> 00:12:16,120
Speaker 1: first great idea, That was the first idea worthy of

267
00:12:16,120 --> 00:12:17,560
Speaker 1: having a light bulb over your head.

268
00:12:19,640 --> 00:12:20,520
Speaker 2: Technically, that's true.

269
00:12:20,559 --> 00:12:23,240
Speaker 1: Yeah, And so the idea for incandescent lights is to

270
00:12:23,320 --> 00:12:27,480
Speaker 1: find some material where you can deposit the energy from

271
00:12:27,520 --> 00:12:31,240
Speaker 1: your electrons and it'll give off lights. Right, So every

272
00:12:31,320 --> 00:12:33,600
Speaker 1: one of these strategies you want to turn fast moving

273
00:12:33,640 --> 00:12:35,800
Speaker 1: electrons into shooting off.

274
00:12:35,640 --> 00:12:39,120
Speaker 2: Photons photons to the surrounding areas. Yeah, okay, So how

275
00:12:39,120 --> 00:12:41,360
Speaker 2: do incandescent lights work? How do light bulbs work?

276
00:12:41,480 --> 00:12:43,720
Speaker 1: Regular One the amazing thing about light bulbs that people

277
00:12:43,720 --> 00:12:46,480
Speaker 1: probably don't understand is that they glow even when they're

278
00:12:46,520 --> 00:12:51,640
Speaker 1: off what. Yeah, everything glows. It's called black body radiation.

279
00:12:51,920 --> 00:12:55,160
Speaker 1: Everything in the universe gives off photons, gives off radiation,

280
00:12:55,679 --> 00:12:57,160
Speaker 1: even if it's totally black.

281
00:12:56,960 --> 00:13:00,240
Speaker 2: Even if it's a black hole. Dad, Well, technically, yes,

282
00:13:00,520 --> 00:13:02,920
Speaker 2: black holes do give a radiation, all right, Yeah, no,

283
00:13:03,000 --> 00:13:04,080
Speaker 2: that's true. I stand correct.

284
00:13:04,160 --> 00:13:06,559
Speaker 1: Yes, even black holes have a temperature. Right, Everything in

285
00:13:06,600 --> 00:13:11,040
Speaker 1: the universe that's not an absolute zero glows at some spectrum. Now,

286
00:13:11,160 --> 00:13:13,600
Speaker 1: usually you don't see it because it's invisible. It glows

287
00:13:13,640 --> 00:13:18,240
Speaker 1: it very very very long wavelengths, very low frequencies, and

288
00:13:18,280 --> 00:13:20,720
Speaker 1: so you don't see it. So, but this is why,

289
00:13:20,760 --> 00:13:24,240
Speaker 1: for example, you know infrared telescopes like the James web

290
00:13:24,280 --> 00:13:28,520
Speaker 1: Space telescope that looks for infrared light, it sees a

291
00:13:28,559 --> 00:13:30,560
Speaker 1: lot of noise that you don't even see and have

292
00:13:30,640 --> 00:13:33,560
Speaker 1: to keep it cold at like negative fifty degrees or whatever.

293
00:13:34,160 --> 00:13:37,360
Speaker 1: So everything in the universe is already glowing, but it's

294
00:13:37,440 --> 00:13:38,240
Speaker 1: not so useful.

295
00:13:38,320 --> 00:13:38,400
Speaker 7: Right.

296
00:13:38,559 --> 00:13:40,560
Speaker 1: What you want is something that glows with light that

297
00:13:40,640 --> 00:13:41,760
Speaker 1: you can see a lot.

298
00:13:41,880 --> 00:13:44,400
Speaker 2: Yeah right, Oh, I see. Black body radiation is in

299
00:13:44,440 --> 00:13:45,040
Speaker 2: the infrared.

300
00:13:45,080 --> 00:13:47,840
Speaker 1: It's much lower than the infrared, yet it's most black

301
00:13:47,840 --> 00:13:51,640
Speaker 1: body radiation, like the cosmic microwave. Background radiation is black

302
00:13:51,679 --> 00:13:55,120
Speaker 1: body radiation from that initial plasma of the universe, and

303
00:13:55,200 --> 00:13:57,439
Speaker 1: it's at like, you know, three degrees kelvin. It's a

304
00:13:57,640 --> 00:13:58,840
Speaker 1: very very long wavelengths.

305
00:13:58,880 --> 00:14:01,400
Speaker 2: But what about something that said zero degreek kelvin, like

306
00:14:01,520 --> 00:14:03,400
Speaker 2: absolute zero, would that still glow?

307
00:14:03,520 --> 00:14:05,920
Speaker 1: No, something that absolute zero can't glow. But there is

308
00:14:05,920 --> 00:14:07,600
Speaker 1: nothing in the universe at absolute zero.

309
00:14:08,240 --> 00:14:12,800
Speaker 2: So if you're like at point one degrees kelvin from

310
00:14:12,840 --> 00:14:15,560
Speaker 2: absolute zero, you would be glowing a little bit exactly.

311
00:14:15,600 --> 00:14:17,520
Speaker 1: And that's why the black hole stuff is actually quite

312
00:14:17,559 --> 00:14:21,200
Speaker 1: fascinating because when Stephen Hawking developed his ideas of black

313
00:14:21,200 --> 00:14:26,280
Speaker 1: holes having a temperature, that automatically suggests that black holes

314
00:14:26,320 --> 00:14:28,600
Speaker 1: should radiate because like everything else that has a temperature,

315
00:14:28,680 --> 00:14:31,320
Speaker 1: they should radiate. And that's why Hawking's results are sort

316
00:14:31,320 --> 00:14:34,800
Speaker 1: of black hole thermodynamics, because he's thinking about the temperature

317
00:14:34,800 --> 00:14:36,880
Speaker 1: of black holes and how that connects to how they radiate.

318
00:14:37,040 --> 00:14:39,240
Speaker 2: All Right, so everything glows in the infrared, So how

319
00:14:39,240 --> 00:14:41,480
Speaker 2: do we get things to glow in the visible light

320
00:14:41,680 --> 00:14:42,640
Speaker 2: the white light spectrum.

321
00:14:42,800 --> 00:14:44,960
Speaker 1: Yeah, so the spectrum in which you glow depends on

322
00:14:45,000 --> 00:14:48,880
Speaker 1: your temperature. So really cold stuff glows in the infrared.

323
00:14:48,920 --> 00:14:51,840
Speaker 1: If you heat something up, then it's emissions move into

324
00:14:51,840 --> 00:14:54,560
Speaker 1: the visible spectrum. So you want to make your filament

325
00:14:54,600 --> 00:14:57,040
Speaker 1: glow in the visible light instead of in the infrared light,

326
00:14:57,200 --> 00:14:58,320
Speaker 1: than what you do is you make it.

327
00:14:58,280 --> 00:15:01,480
Speaker 2: Hot, hotter and hotter. It turns the light from it

328
00:15:01,560 --> 00:15:03,720
Speaker 2: not just glows more, but it changes color.

329
00:15:03,760 --> 00:15:06,160
Speaker 1: It changes color. And that's why, for example, you heat

330
00:15:06,240 --> 00:15:08,240
Speaker 1: up metal, right and you see it glows blue, it

331
00:15:08,240 --> 00:15:11,320
Speaker 1: glows red, it glows white, for example. And the temperature

332
00:15:11,560 --> 00:15:14,440
Speaker 1: of the metal determines the frequency at which it's glowing, right,

333
00:15:14,480 --> 00:15:18,640
Speaker 1: Like white hot and red hot are different temperatures of metal, right.

334
00:15:19,120 --> 00:15:20,480
Speaker 1: And so this is a basic principle.

335
00:15:20,520 --> 00:15:22,560
Speaker 2: And what's going on in the physics sense, like what's

336
00:15:22,560 --> 00:15:24,440
Speaker 2: going on with the electrons and the atoms, why is

337
00:15:24,480 --> 00:15:27,200
Speaker 2: it changing color? And how is it giving off the light.

338
00:15:27,320 --> 00:15:28,960
Speaker 1: So it's always a good idea to try to think

339
00:15:28,960 --> 00:15:31,360
Speaker 1: about stuff microscopically. And that's not just because I'm a

340
00:15:31,440 --> 00:15:33,760
Speaker 1: particle physicist that I think we should always be thinking

341
00:15:33,840 --> 00:15:36,280
Speaker 1: about the tiny stuff. I think it really does lead

342
00:15:36,280 --> 00:15:39,880
Speaker 1: to some insight. And so what's happening microscopically when you

343
00:15:39,960 --> 00:15:42,600
Speaker 1: heat something up is that the electrons inside it, the

344
00:15:42,640 --> 00:15:45,960
Speaker 1: particles inside it, have more ways to move. They're wiggling more,

345
00:15:45,960 --> 00:15:48,440
Speaker 1: and they're bouncing more, so there's just a lot more

346
00:15:48,560 --> 00:15:52,400
Speaker 1: energy there. Now. The way something glows is when something

347
00:15:52,480 --> 00:15:55,360
Speaker 1: moves from a higher energy level to a lower energy level.

348
00:15:55,440 --> 00:15:58,160
Speaker 2: I mean, like the atoms in it decay or sort

349
00:15:58,160 --> 00:16:00,480
Speaker 2: of degrade a little bit or chill out. And when

350
00:16:00,480 --> 00:16:01,960
Speaker 2: they do that, they emit a photon.

351
00:16:02,080 --> 00:16:04,720
Speaker 1: Yeah, they're excited. They have some energy stored in them,

352
00:16:04,760 --> 00:16:07,080
Speaker 1: and that energy comes from you know, whatever you did

353
00:16:07,280 --> 00:16:11,120
Speaker 1: to heat up this material. Right. Heat means internal energy

354
00:16:11,120 --> 00:16:13,440
Speaker 1: stored in the motion of these objects. And we had

355
00:16:13,480 --> 00:16:16,160
Speaker 1: a whole podcast about what temperature means and it turns

356
00:16:16,160 --> 00:16:19,400
Speaker 1: out to be very confusing and amazing, like everything else

357
00:16:19,440 --> 00:16:20,920
Speaker 1: in the universe. But the way to think about it

358
00:16:21,000 --> 00:16:25,240
Speaker 1: microscopically is that these atoms are excited. Either the electrons

359
00:16:25,280 --> 00:16:27,960
Speaker 1: that are whizzing around them have gone up one ladder

360
00:16:28,000 --> 00:16:30,400
Speaker 1: in the energy level or two ladders or three ladders,

361
00:16:30,920 --> 00:16:33,440
Speaker 1: or maybe they're vibrating in new ways or rotating in

362
00:16:33,480 --> 00:16:35,880
Speaker 1: new ways. These are all ways that they can store energy.

363
00:16:36,000 --> 00:16:37,640
Speaker 2: The electrons are the atoms.

364
00:16:37,720 --> 00:16:39,880
Speaker 1: The electrons can move up energy levels, but the atoms

365
00:16:39,920 --> 00:16:42,480
Speaker 1: also they can vibrate. Remember, a lot of these are

366
00:16:42,480 --> 00:16:45,280
Speaker 1: in bonds, right. Metals are not just free floating gases.

367
00:16:45,520 --> 00:16:48,440
Speaker 1: There are these lattices of things tied together and they're

368
00:16:48,480 --> 00:16:50,920
Speaker 1: like you can imagine little springs between them, and then

369
00:16:51,200 --> 00:16:53,920
Speaker 1: you can imagine those things vibrating and vibrating in different ways.

370
00:16:53,920 --> 00:16:55,880
Speaker 1: They have different modes, all right.

371
00:16:55,920 --> 00:16:58,680
Speaker 2: So they're excited and so they they're giving of energy.

372
00:16:58,480 --> 00:17:00,760
Speaker 1: And then they relax because things universe don't like to

373
00:17:00,800 --> 00:17:02,960
Speaker 1: be excited. They like to spread out their energy. And

374
00:17:02,960 --> 00:17:06,080
Speaker 1: that's why things emit energy because entropy, right, energy in

375
00:17:06,080 --> 00:17:08,520
Speaker 1: the universe tends to diffuse, and so if you have

376
00:17:08,600 --> 00:17:11,640
Speaker 1: it concentrated in one little mode, like one little electron

377
00:17:11,680 --> 00:17:14,480
Speaker 1: has jumped up three energy levels, it will decay. You'll

378
00:17:14,640 --> 00:17:16,879
Speaker 1: give that energy off. And the way it does that

379
00:17:17,000 --> 00:17:18,320
Speaker 1: is by shooting off a photon.

380
00:17:18,640 --> 00:17:20,399
Speaker 2: And so the more you heat up something up, the

381
00:17:20,400 --> 00:17:23,320
Speaker 2: more you make all the atoms more excited, the more

382
00:17:23,760 --> 00:17:25,800
Speaker 2: you know photons that are going to come off of

383
00:17:25,880 --> 00:17:27,119
Speaker 2: this excitment.

384
00:17:26,640 --> 00:17:29,359
Speaker 1: Exactly, and then the higher the energy of those gaps,

385
00:17:29,359 --> 00:17:32,199
Speaker 1: So an electron can get pushed up several levels up

386
00:17:32,200 --> 00:17:34,640
Speaker 1: that ladder, and then it can jump down five levels,

387
00:17:34,880 --> 00:17:37,960
Speaker 1: and so then the photon has more energy, which corresponds

388
00:17:38,000 --> 00:17:41,879
Speaker 1: to a higher frequency. So that's how for example, hot

389
00:17:41,880 --> 00:17:44,679
Speaker 1: objects can emit in the visible spectrum instead of just

390
00:17:44,720 --> 00:17:47,120
Speaker 1: at the very very low energy levels. So the light

391
00:17:47,200 --> 00:17:50,200
Speaker 1: that they emit has more energy, which is what higher

392
00:17:50,320 --> 00:17:53,600
Speaker 1: frequency means, which is what visible light means, or in

393
00:17:53,640 --> 00:17:57,719
Speaker 1: visible light has more energy per photon than infrared light.

394
00:17:57,760 --> 00:18:00,200
Speaker 2: But I think it also has to be certain kind

395
00:18:00,280 --> 00:18:02,840
Speaker 2: of materials, right, Like when I boil water, it doesn't

396
00:18:02,880 --> 00:18:05,040
Speaker 2: start to glow. I mean it starts to glow in

397
00:18:05,080 --> 00:18:06,840
Speaker 2: the infrared, but not in the visible light.

398
00:18:06,840 --> 00:18:09,359
Speaker 1: Spiker, that's an awesome question. How hot would you have

399
00:18:09,440 --> 00:18:11,960
Speaker 1: to make water in order to make it glow? I

400
00:18:12,000 --> 00:18:13,840
Speaker 1: don't know the answer to that. That's a cool question.

401
00:18:13,920 --> 00:18:15,960
Speaker 1: But you're right, Yeah, everything glows at some level, but

402
00:18:16,240 --> 00:18:18,439
Speaker 1: not everything can be easily made to glow in the.

403
00:18:18,440 --> 00:18:21,640
Speaker 2: Business because I guess it'll melt or burn or boil.

404
00:18:21,640 --> 00:18:24,600
Speaker 1: Yeah, exactly, something else will happen to it turn into vapor.

405
00:18:24,640 --> 00:18:26,800
Speaker 2: And so that's how light bulbs work. It's that they

406
00:18:26,800 --> 00:18:29,800
Speaker 2: have a little thin wire of metal that you heat

407
00:18:29,880 --> 00:18:31,560
Speaker 2: up and then that gives us the light.

408
00:18:31,760 --> 00:18:33,760
Speaker 1: That's right. And the way you heat it up is

409
00:18:33,760 --> 00:18:36,320
Speaker 1: that you send current through it, right, You send electricity

410
00:18:36,359 --> 00:18:39,760
Speaker 1: through it, and most of these metals are resistors, meaning

411
00:18:40,000 --> 00:18:43,000
Speaker 1: that they are not perfect conductors. So the electrons as

412
00:18:43,000 --> 00:18:45,440
Speaker 1: they're trying to go through the metal are getting bounced

413
00:18:45,480 --> 00:18:48,480
Speaker 1: into atoms, right, and those atoms are stealing their energy.

414
00:18:49,080 --> 00:18:52,320
Speaker 1: And this is what heats up something when electricity passes

415
00:18:52,359 --> 00:18:54,879
Speaker 1: through it. Like you know that block that you use

416
00:18:55,000 --> 00:18:56,919
Speaker 1: to charge your laptop. Have you've been charging it for

417
00:18:56,920 --> 00:19:00,400
Speaker 1: a while, it heats up, right, that's using, that's in efficient,

418
00:19:00,440 --> 00:19:04,280
Speaker 1: it's using. It's stealing the electricity from those electrons in

419
00:19:04,400 --> 00:19:07,080
Speaker 1: order to heat up that blot. This is how you

420
00:19:07,119 --> 00:19:09,400
Speaker 1: heat up the filament of tungsten, is you pass all

421
00:19:09,440 --> 00:19:11,919
Speaker 1: this electricity through it. That heats it up and that

422
00:19:12,000 --> 00:19:12,600
Speaker 1: makes it glow.

423
00:19:12,880 --> 00:19:15,640
Speaker 2: Yeah, that's a little wire inside of the traditional light

424
00:19:15,640 --> 00:19:17,800
Speaker 2: bulb and white tungsten. Is it a special kind of

425
00:19:17,800 --> 00:19:19,720
Speaker 2: metal that can heat up a lot without melting.

426
00:19:19,840 --> 00:19:22,159
Speaker 1: Yeah, tungsten just sort of lasts a long time. But

427
00:19:22,240 --> 00:19:25,840
Speaker 1: these things are really very very inefficient. Like it's not

428
00:19:25,880 --> 00:19:28,880
Speaker 1: a very direct way to get energy into photons. Right,

429
00:19:29,359 --> 00:19:31,680
Speaker 1: You're just heating this thing up and it's glowing somewhat

430
00:19:31,680 --> 00:19:34,240
Speaker 1: in the visible but not always in the visible, and

431
00:19:34,440 --> 00:19:35,840
Speaker 1: a lot of the energy is just lost.

432
00:19:36,600 --> 00:19:39,440
Speaker 2: A lot of the energy goes into the infrared, which

433
00:19:40,080 --> 00:19:41,120
Speaker 2: is useless to us.

434
00:19:41,200 --> 00:19:43,639
Speaker 1: Yeah, it just goes into making this thing hot, right,

435
00:19:44,000 --> 00:19:46,440
Speaker 1: and not all the heat gets turned into visible light.

436
00:19:47,200 --> 00:19:50,200
Speaker 1: And so only something like five percent of the energy

437
00:19:50,200 --> 00:19:52,600
Speaker 1: that you put into a light bulb gets turned into light.

438
00:19:52,640 --> 00:19:52,920
Speaker 6: Wow.

439
00:19:53,119 --> 00:19:53,879
Speaker 2: Not super efficient.

440
00:19:54,000 --> 00:19:56,920
Speaker 1: Not super efficient, and also kind of fragile, like you're

441
00:19:57,000 --> 00:19:59,440
Speaker 1: baking this thing every single time. So it gets hot

442
00:19:59,480 --> 00:20:01,040
Speaker 1: and then it gets cold, and it gets hot and

443
00:20:01,080 --> 00:20:03,320
Speaker 1: then it gets cold, and you know that, like that

444
00:20:03,560 --> 00:20:06,240
Speaker 1: creates a lot of mechanical stress, which is why these filaments,

445
00:20:06,280 --> 00:20:09,439
Speaker 1: which are already very very thin, don't last for that long.

446
00:20:09,720 --> 00:20:13,280
Speaker 1: So your typical incandescent classic light bulb only works for

447
00:20:13,320 --> 00:20:14,560
Speaker 1: about a thousand hours.

448
00:20:14,720 --> 00:20:16,880
Speaker 2: Well they're making a comeback, you know, and like hip

449
00:20:17,080 --> 00:20:20,240
Speaker 2: restaurants and stuff, everyone's going for the incandescent bulbs. Yeah.

450
00:20:20,280 --> 00:20:22,760
Speaker 1: Well, the positive thing about incandescent bulbs is to have

451
00:20:22,800 --> 00:20:25,520
Speaker 1: a very nice glow, like it feels like sort of

452
00:20:25,600 --> 00:20:28,679
Speaker 1: a natural light. You know. The process that produces this

453
00:20:28,800 --> 00:20:31,879
Speaker 1: light gives you a spread, right, not just one color.

454
00:20:32,040 --> 00:20:33,840
Speaker 1: It's not like a laser beam in your eye. It's

455
00:20:33,840 --> 00:20:36,679
Speaker 1: a nice spread, a warm white light. And so a

456
00:20:36,680 --> 00:20:38,680
Speaker 1: lot of people like that. It's sort of more similar

457
00:20:38,680 --> 00:20:41,000
Speaker 1: to sunlight than some of the other technologies we're going

458
00:20:41,040 --> 00:20:41,720
Speaker 1: to talk about seeing.

459
00:20:41,720 --> 00:20:43,800
Speaker 2: All right, let's get into some of these other technologies

460
00:20:43,920 --> 00:20:47,880
Speaker 2: like LEDs, like fluorescent light bulbs, But first let's take

461
00:20:47,880 --> 00:20:48,520
Speaker 2: a quick break.

462
00:20:52,840 --> 00:20:55,760
Speaker 1: With big wireless providers, what you see is never what

463
00:20:55,920 --> 00:20:58,600
Speaker 1: you get. Somewhere between the store and your first month's bill,

464
00:20:58,640 --> 00:21:01,560
Speaker 1: the price that you thought you were paying magically skyrockets.

465
00:21:01,600 --> 00:21:04,520
Speaker 1: With mint Mobile, You'll never have to worry about gotcha's

466
00:21:04,600 --> 00:21:07,320
Speaker 1: ever again. When Mint Mobile says fifteen dollars a month

467
00:21:07,359 --> 00:21:09,840
Speaker 1: for a three month plan, they really mean it. I've

468
00:21:09,920 --> 00:21:12,199
Speaker 1: used mint Mobile and the call quality is always so

469
00:21:12,320 --> 00:21:14,679
Speaker 1: crisp and so clear. I can recommend it to you.

470
00:21:14,960 --> 00:21:17,680
Speaker 1: So say bye bye to your overpriced wireless plans, jaw

471
00:21:17,800 --> 00:21:21,120
Speaker 1: dropping monthly bills and unexpected overages. You can use your

472
00:21:21,160 --> 00:21:23,760
Speaker 1: own phone with any Mint Mobile plan and bring your

473
00:21:23,800 --> 00:21:26,879
Speaker 1: phone number along with your existing contacts. So dit your

474
00:21:26,880 --> 00:21:29,520
Speaker 1: overpriced wireless with mint Mobiles deal and get three months

475
00:21:29,560 --> 00:21:32,320
Speaker 1: a premium wireless service for fifteen bucks a month. To

476
00:21:32,359 --> 00:21:34,280
Speaker 1: get this new customer offer and your new three month

477
00:21:34,359 --> 00:21:36,480
Speaker 1: premium wireless plan for just fifteen bucks a month, go

478
00:21:36,520 --> 00:21:39,840
Speaker 1: to mintmobile dot com slash universe. That's mintmobile dot com

479
00:21:39,880 --> 00:21:42,520
Speaker 1: slash universe. Cut your wireless bill to fifteen bucks a month.

480
00:21:42,520 --> 00:21:45,520
Speaker 1: At mintmobile dot com slash Universe, forty five dollars upfront

481
00:21:45,560 --> 00:21:48,440
Speaker 1: payment required equivalent to fifteen dollars per month New customers

482
00:21:48,480 --> 00:21:50,920
Speaker 1: on first three month plan only speeds slower about forty

483
00:21:50,960 --> 00:21:53,920
Speaker 1: gigabytes on unlimited plan. Additional taxi spees and restrictions apply.

484
00:21:54,000 --> 00:21:55,400
Speaker 1: See mint mobile for details.

485
00:21:55,600 --> 00:21:58,600
Speaker 8: AI might be the most important new computer technology ever.

486
00:21:58,880 --> 00:22:02,119
Speaker 8: It's storming every end and literally billions of dollars are

487
00:22:02,119 --> 00:22:06,359
Speaker 8: being invested, so buckle up. The problem is that AI

488
00:22:06,480 --> 00:22:09,320
Speaker 8: needs a lot of speed and processing power, So how

489
00:22:09,320 --> 00:22:12,480
Speaker 8: do you compete without cost spiraling out of control. It's

490
00:22:12,520 --> 00:22:14,840
Speaker 8: time to upgrade to the next generation of the cloud.

491
00:22:15,160 --> 00:22:20,320
Speaker 8: Oracle Cloud Infrastructure or OCI. OCI is a single platform

492
00:22:20,359 --> 00:22:25,240
Speaker 8: for your infrastructure, database, application development, and AI needs. OCI

493
00:22:25,400 --> 00:22:27,760
Speaker 8: has four to eight times the bandwidth of other clouds,

494
00:22:28,119 --> 00:22:31,720
Speaker 8: offers one consistent price instead of variable regional pricing, and

495
00:22:31,760 --> 00:22:34,880
Speaker 8: of course nobody does data better than Oracle. So now

496
00:22:34,920 --> 00:22:37,119
Speaker 8: you can train your AI models at twice the speed

497
00:22:37,320 --> 00:22:39,680
Speaker 8: and less than half the cost of other clouds. If

498
00:22:39,680 --> 00:22:41,880
Speaker 8: you want to do more and spend less like Uber

499
00:22:42,040 --> 00:22:44,680
Speaker 8: eight by eight and Data Bricks Mosaic. Take a free

500
00:22:44,680 --> 00:22:48,600
Speaker 8: test drive of OCI at Oracle dot com slash Strategic.

501
00:22:48,920 --> 00:22:54,159
Speaker 8: That's Oracle dot com slash Strategic. Oracle dot com slash Strategic.

502
00:22:54,440 --> 00:22:57,359
Speaker 1: If you love iPhone, you'll love Apple Card. It's the

503
00:22:57,440 --> 00:23:01,320
Speaker 1: credit card designed for iPhone. It gives you unlimited daily

504
00:23:01,400 --> 00:23:04,400
Speaker 1: cash back that can earn four point four zero percent

505
00:23:04,520 --> 00:23:07,320
Speaker 1: annual percentage yield. When you open a high Yield savings

506
00:23:07,359 --> 00:23:10,199
Speaker 1: account through Apple Card, apply for Apple Card in the

507
00:23:10,280 --> 00:23:13,560
Speaker 1: wallet app, subject to credit approval. Savings is available to

508
00:23:13,600 --> 00:23:17,040
Speaker 1: Apple Card owners subject to eligibility. Apple Card and Savings

509
00:23:17,040 --> 00:23:19,920
Speaker 1: by Goldman Sachs Bank USA, Salt Lake City Branch Member,

510
00:23:20,040 --> 00:23:32,160
Speaker 1: FDIC terms and more at applecard dot com.

511
00:23:32,320 --> 00:23:35,800
Speaker 2: Right there, we're talking about how LEDs work and specifically

512
00:23:35,800 --> 00:23:37,879
Speaker 2: how lights work in general. So we're going down the

513
00:23:37,920 --> 00:23:41,280
Speaker 2: list of technologies, and so we talked about incandescent bulbs,

514
00:23:41,320 --> 00:23:44,399
Speaker 2: which I'm guessing maybe my kids will never have to

515
00:23:44,480 --> 00:23:47,639
Speaker 2: know how they work technically because everything has sort of

516
00:23:47,680 --> 00:23:49,720
Speaker 2: moved on. But the next one in the history of

517
00:23:49,800 --> 00:23:52,120
Speaker 2: light is the fluorescent light bulb. So you were saying

518
00:23:52,119 --> 00:23:54,040
Speaker 2: these were invented at around the same time as the

519
00:23:54,040 --> 00:23:57,680
Speaker 2: incandescent light bulb, but they worked on a totally different physical.

520
00:23:57,480 --> 00:23:59,600
Speaker 1: Yeah, the physics is different. The idea here is to

521
00:23:59,640 --> 00:24:02,240
Speaker 1: use ex gas and you know we talked about in

522
00:24:02,240 --> 00:24:06,520
Speaker 1: the late eighteen hundreds, people were making vacuum tubes and

523
00:24:06,640 --> 00:24:09,320
Speaker 1: you know, passing currents through it and seeing glows. And

524
00:24:09,359 --> 00:24:11,480
Speaker 1: that's actually one of the things that led to the

525
00:24:11,560 --> 00:24:14,359
Speaker 1: discovery of the electron, right. J. J. Thompson discovered the

526
00:24:14,359 --> 00:24:17,359
Speaker 1: electron by playing with these sort of evacuated tubes and

527
00:24:17,400 --> 00:24:20,280
Speaker 1: seeing how the gas inside them glows. But then people

528
00:24:20,280 --> 00:24:22,639
Speaker 1: were playing with other kinds of things and discovered that

529
00:24:22,720 --> 00:24:25,560
Speaker 1: if you pass a current through a tube that has

530
00:24:25,640 --> 00:24:28,359
Speaker 1: gas in it, you can make the gas glow. And

531
00:24:28,400 --> 00:24:31,600
Speaker 1: the physics here is pretty similar to the physics of

532
00:24:31,680 --> 00:24:34,800
Speaker 1: incandescent lights, except that you're making a gas glow instead

533
00:24:34,800 --> 00:24:37,120
Speaker 1: of making like a piece of metal glow.

534
00:24:36,920 --> 00:24:38,879
Speaker 2: I see, instead of a little wire, it's like a

535
00:24:38,920 --> 00:24:39,679
Speaker 2: tube of gas.

536
00:24:39,760 --> 00:24:43,080
Speaker 1: Yeah, and you can excite the electrons in that gas.

537
00:24:43,320 --> 00:24:45,520
Speaker 1: They go up an energy level and then they jump

538
00:24:45,560 --> 00:24:47,400
Speaker 1: back down and they give off a photon.

539
00:24:48,000 --> 00:24:49,920
Speaker 2: And I think last time we talked about these, it

540
00:24:50,320 --> 00:24:53,080
Speaker 2: sort of related to lightning the way kind of it's

541
00:24:53,160 --> 00:24:54,920
Speaker 2: it's almost like you're creating a little bit of lightning

542
00:24:54,960 --> 00:24:55,359
Speaker 2: in a bottle.

543
00:24:55,440 --> 00:24:57,240
Speaker 1: Yeah, it's lightning in a bottle, and it's a little

544
00:24:57,240 --> 00:25:00,320
Speaker 1: bit of plasma. Right. In order to pass electric city

545
00:25:00,320 --> 00:25:02,840
Speaker 1: through a gas, you have to turn it into ions.

546
00:25:02,880 --> 00:25:05,560
Speaker 1: You have to tear apart the positive and the negative

547
00:25:05,560 --> 00:25:07,920
Speaker 1: that usually the gas is made out of and make

548
00:25:07,960 --> 00:25:10,400
Speaker 1: an ion channel. And you know this sounds like star

549
00:25:10,480 --> 00:25:13,919
Speaker 1: Trek or whatever, but you're literally making a tube of

550
00:25:14,400 --> 00:25:18,280
Speaker 1: electrically charged gas. It's like a gaseous wire sort of cool.

551
00:25:18,280 --> 00:25:21,679
Speaker 1: It's like a gas that conducts electricity, right, and so

552
00:25:21,760 --> 00:25:24,680
Speaker 1: you're tearing it apart just by creating this electric field

553
00:25:24,680 --> 00:25:27,159
Speaker 1: from one side to the other and then passing that

554
00:25:27,320 --> 00:25:29,800
Speaker 1: energy through and it excites the gas. It makes the

555
00:25:29,800 --> 00:25:30,320
Speaker 1: gas like.

556
00:25:30,280 --> 00:25:33,560
Speaker 2: The atoms of the gas inside are now giving off.

557
00:25:33,640 --> 00:25:36,240
Speaker 2: They're like absorbing these electrons that are going through and

558
00:25:36,240 --> 00:25:37,560
Speaker 2: then they give them off as photon.

559
00:25:37,640 --> 00:25:40,840
Speaker 1: That's right. The microphysics of what's happening is that these electrons,

560
00:25:40,840 --> 00:25:43,639
Speaker 1: the current that's passing through will sometimes bump into an

561
00:25:43,680 --> 00:25:47,080
Speaker 1: electron in the gas atom and bump it up a

562
00:25:47,119 --> 00:25:49,679
Speaker 1: few energy levels, and then it'll fall back down and

563
00:25:49,720 --> 00:25:52,000
Speaker 1: when it does that, it gives off a photon. So

564
00:25:52,040 --> 00:25:55,640
Speaker 1: you're turning the kinetic energy of some initial electron into

565
00:25:55,680 --> 00:25:59,280
Speaker 1: an excited state of the atomic electron, which then emits

566
00:25:59,280 --> 00:26:01,480
Speaker 1: a photon. So that's how you get energy from the

567
00:26:01,520 --> 00:26:03,000
Speaker 1: electron into a photon.

568
00:26:03,040 --> 00:26:05,760
Speaker 2: And it's kind of a binary process, right, Like it's

569
00:26:05,760 --> 00:26:09,000
Speaker 2: hard to dim a fluorescent light bulb, right, Like a

570
00:26:09,040 --> 00:26:11,520
Speaker 2: little regular bulb, you can do that, but a fluorescent

571
00:26:11,560 --> 00:26:13,240
Speaker 2: you know, it's either on and off or and if

572
00:26:13,240 --> 00:26:15,600
Speaker 2: it's sort of on the edge, you'll blink and kind

573
00:26:15,640 --> 00:26:16,400
Speaker 2: of give you ice stream.

574
00:26:16,400 --> 00:26:18,520
Speaker 1: That's right, Because you need to create this plasma, you

575
00:26:18,560 --> 00:26:20,400
Speaker 1: need to like ramp it up to a high enough

576
00:26:20,480 --> 00:26:23,280
Speaker 1: voltage so that you can create this ion channel and

577
00:26:23,320 --> 00:26:25,840
Speaker 1: the whole thing starts up. It's almost like starting up

578
00:26:25,840 --> 00:26:28,680
Speaker 1: a little fusion reactor inside. Oh my god, it's sort

579
00:26:28,680 --> 00:26:29,040
Speaker 1: of awesome.

580
00:26:29,080 --> 00:26:31,960
Speaker 2: Yeah, Suddenly, florescent light bulbs are way cooler. They're lightning

581
00:26:32,040 --> 00:26:33,960
Speaker 2: in a bottle and fusion bombs two.

582
00:26:34,040 --> 00:26:35,920
Speaker 1: Yeah. And the cool thing about them is that they're

583
00:26:35,920 --> 00:26:38,639
Speaker 1: a lot more efficient doing this with gas, Like a

584
00:26:38,720 --> 00:26:41,560
Speaker 1: mercury vapor, which is what's typically used, is something like

585
00:26:41,640 --> 00:26:44,919
Speaker 1: twenty percent efficient instead of like the five percent of

586
00:26:44,960 --> 00:26:46,120
Speaker 1: your incandescent light bulb.

587
00:26:46,200 --> 00:26:49,080
Speaker 2: Where does the other seventy eight percent efficiency go into

588
00:26:49,200 --> 00:26:51,880
Speaker 2: heat as well? But they don't get us.

589
00:26:51,800 --> 00:26:54,160
Speaker 1: Well, that's exactly right. They don't get as hot, which

590
00:26:54,160 --> 00:26:56,960
Speaker 1: is why they're more efficient. Right, So more the energy

591
00:26:57,000 --> 00:26:59,200
Speaker 1: goes into creating light and less of it goes into

592
00:26:59,240 --> 00:27:02,000
Speaker 1: like heating up the actual apparatus. So I think that

593
00:27:02,040 --> 00:27:05,160
Speaker 1: all makes sense. One interesting facet which I thought was cool,

594
00:27:05,280 --> 00:27:07,720
Speaker 1: was that the best thing to use to make this

595
00:27:07,920 --> 00:27:11,160
Speaker 1: light is mercury vapor because you don't need really high

596
00:27:11,240 --> 00:27:13,680
Speaker 1: voltage and it's it's one of the most efficient ways

597
00:27:13,680 --> 00:27:17,560
Speaker 1: to do it. But mercury is like super poisonous, which

598
00:27:17,680 --> 00:27:21,440
Speaker 1: makes it like it's a bad idea. Also, mercury gives

599
00:27:21,440 --> 00:27:24,840
Speaker 1: off light, it's not visible. It gives off ultra violet light.

600
00:27:24,960 --> 00:27:27,480
Speaker 2: Oh my goodness. Yeah, poisons you and gives you cancer

601
00:27:27,560 --> 00:27:28,359
Speaker 2: at the same time.

602
00:27:29,000 --> 00:27:30,919
Speaker 1: No, but that's why a lot of these fluorescent light

603
00:27:30,920 --> 00:27:34,520
Speaker 1: bulbs are not clear. They're frosted because the inner side

604
00:27:34,560 --> 00:27:38,800
Speaker 1: of the glass contains another material which absorbs the ultra

605
00:27:38,920 --> 00:27:41,520
Speaker 1: violet light, uses some of the energy, and then gives

606
00:27:41,560 --> 00:27:43,480
Speaker 1: off light in the visible So it's like a two

607
00:27:43,600 --> 00:27:47,840
Speaker 1: step process. The mercury vapor gives off UV photons which

608
00:27:47,840 --> 00:27:51,000
Speaker 1: are then like stepped down into the visible light by

609
00:27:51,000 --> 00:27:53,720
Speaker 1: some phosphorescent coating inside the bowl.

610
00:27:54,480 --> 00:27:55,199
Speaker 2: So a lot to it.

611
00:27:55,400 --> 00:27:57,919
Speaker 1: Yeah, it's a complicated thing, and you know, you have

612
00:27:58,000 --> 00:27:59,960
Speaker 1: to create this plasma. And that's why fluorescent light bulb

613
00:28:00,160 --> 00:28:03,040
Speaker 1: until recently not as commonly used in the home. They're

614
00:28:03,160 --> 00:28:06,480
Speaker 1: more expensive and more complicated, but they're a lot more efficient,

615
00:28:06,640 --> 00:28:10,040
Speaker 1: like twenty percent instead of five percent, and they work

616
00:28:10,080 --> 00:28:13,160
Speaker 1: for like ten thousand hours instead of a thousand hours.

617
00:28:13,200 --> 00:28:16,000
Speaker 2: And the light is kind of different too. It's wier generally,

618
00:28:16,080 --> 00:28:18,720
Speaker 2: it's wider, Yeah, and it kind of drives me bunkers,

619
00:28:18,760 --> 00:28:20,480
Speaker 2: Like I don't like the light from fluorescent light bulbs.

620
00:28:20,480 --> 00:28:22,359
Speaker 2: It makes me feel like I'm, you know, in a

621
00:28:22,440 --> 00:28:26,600
Speaker 2: target or in like an alien autopsy examination room. Oh lot,

622
00:28:28,119 --> 00:28:30,880
Speaker 2: target and alien autopsy. That's where your mind goes. It's

623
00:28:31,000 --> 00:28:32,800
Speaker 2: worse worse case scenarios.

624
00:28:33,000 --> 00:28:34,680
Speaker 1: Well, actually, now that I think about it, I'd love

625
00:28:34,760 --> 00:28:36,720
Speaker 1: to be in an alien autopsy.

626
00:28:36,400 --> 00:28:38,760
Speaker 2: Yeah, or target for that, to be honest.

627
00:28:39,880 --> 00:28:41,880
Speaker 1: It's just that I don't know why the lighting in

628
00:28:42,040 --> 00:28:46,000
Speaker 1: alien autopsy scenes in science fiction is always so terrible, like,

629
00:28:46,040 --> 00:28:49,200
Speaker 1: what are they always use the horrible florists and flickering lights?

630
00:28:49,320 --> 00:28:51,640
Speaker 2: I see, Well, it's just so that the green comes

631
00:28:51,640 --> 00:28:53,480
Speaker 2: out of their skin more. You know, it makes this

632
00:28:53,680 --> 00:28:55,400
Speaker 2: there's green skin seem lovelier.

633
00:28:55,440 --> 00:28:57,760
Speaker 1: I see. The alien's agent insisted that they have it

634
00:28:57,760 --> 00:29:01,360
Speaker 1: that way, is in their contract. All right, Well, brown

635
00:29:01,480 --> 00:29:03,280
Speaker 1: m and m's and fluorescent lights pace.

636
00:29:03,160 --> 00:29:10,800
Speaker 2: Right, that's right and able. I didn't think that would

637
00:29:10,800 --> 00:29:12,000
Speaker 2: make you laugh so much, Daniel.

638
00:29:12,200 --> 00:29:14,240
Speaker 1: I don't think aliens are so vain, all right.

639
00:29:14,240 --> 00:29:18,440
Speaker 2: All right, well hopefully not. But yeah, so that's incandescent

640
00:29:18,480 --> 00:29:20,720
Speaker 2: and fluorescent lights. And so let's get into the topic

641
00:29:20,760 --> 00:29:23,240
Speaker 2: of the podcast, which is how LED lights work. And

642
00:29:23,280 --> 00:29:26,240
Speaker 2: these are pretty recent. I feel like in the last

643
00:29:26,280 --> 00:29:29,640
Speaker 2: ten years they've become more popular. And they're also sort

644
00:29:29,680 --> 00:29:32,560
Speaker 2: of everywhere, right, They're in phones, they're in TVs or

645
00:29:32,800 --> 00:29:35,240
Speaker 2: pretty much every kind of screen, even on people's watches.

646
00:29:35,280 --> 00:29:38,160
Speaker 2: Now I have LEDs, and so, first of all, Daniel,

647
00:29:38,200 --> 00:29:39,360
Speaker 2: what does LED stand for.

648
00:29:39,520 --> 00:29:44,160
Speaker 1: It sends for light emitting diode. Light emitting is obvious, right,

649
00:29:44,320 --> 00:29:48,320
Speaker 1: giving off light, and diode is this little physical thing

650
00:29:48,400 --> 00:29:51,960
Speaker 1: that was invented in the fifties and sixties. That's made

651
00:29:51,960 --> 00:29:55,280
Speaker 1: out of semiconductors. And that's really the core idea here

652
00:29:55,320 --> 00:29:58,120
Speaker 1: is that instead of using a hot little tube of

653
00:29:58,160 --> 00:30:01,080
Speaker 1: metal or a hot tube of gas, let's see if

654
00:30:01,080 --> 00:30:03,160
Speaker 1: we can build this thing out of semiconductors.

655
00:30:03,440 --> 00:30:06,480
Speaker 2: And semiconductors are what computer chips are made out of, right,

656
00:30:06,520 --> 00:30:09,520
Speaker 2: I mean, that's what computers are made out of. So

657
00:30:09,600 --> 00:30:12,560
Speaker 2: this is kind of like they adapted that technology or

658
00:30:12,600 --> 00:30:14,600
Speaker 2: they figured out they can also use it to midlight.

659
00:30:14,640 --> 00:30:16,440
Speaker 1: They can also use it to emit light, and you're right,

660
00:30:16,480 --> 00:30:20,760
Speaker 1: semiconductors are incredible also the basis of transistors, which is

661
00:30:20,760 --> 00:30:23,160
Speaker 1: how we build computer chips. One of the cool things

662
00:30:23,200 --> 00:30:25,840
Speaker 1: about semiconductors is that we can print them really finely.

663
00:30:25,880 --> 00:30:29,200
Speaker 1: We can construct super tiny circuits that have really specific

664
00:30:29,200 --> 00:30:32,840
Speaker 1: semiconductors using lithography, and that's how we make computer chips

665
00:30:32,880 --> 00:30:36,520
Speaker 1: so small. We can make LEDs really small. But first

666
00:30:36,560 --> 00:30:39,040
Speaker 1: maybe we should talk about like what a semiconductor is. Like,

667
00:30:39,480 --> 00:30:41,880
Speaker 1: it's not somebody who's like driving a semi.

668
00:30:41,600 --> 00:30:45,080
Speaker 2: For example, someone who's driving with one eye closed.

669
00:30:46,240 --> 00:30:48,320
Speaker 1: Or conducting an orchestra, but only half the.

670
00:30:48,320 --> 00:30:51,040
Speaker 2: Time, yeah, looking at their phone.

671
00:30:50,760 --> 00:30:53,040
Speaker 1: And so to understand semiconductor you have to understand where

672
00:30:53,040 --> 00:30:55,880
Speaker 1: it falls sort of between other objects like an insulator

673
00:30:56,040 --> 00:30:56,760
Speaker 1: and a conductor.

674
00:30:56,840 --> 00:31:00,520
Speaker 2: It's basically like a conductor that you can control, right,

675
00:31:00,600 --> 00:31:03,080
Speaker 2: like it's a resistor, but you can also shut it

676
00:31:03,120 --> 00:31:04,560
Speaker 2: off if you give it a different signal.

677
00:31:04,760 --> 00:31:06,080
Speaker 1: Sort of. Yeah, I think if it's sort of like

678
00:31:06,120 --> 00:31:09,600
Speaker 1: a combination between an insulator and a conductor, because in

679
00:31:09,640 --> 00:31:13,560
Speaker 1: an insulator, electrons cannot jump between atoms, like one atom

680
00:31:13,600 --> 00:31:15,840
Speaker 1: has its electrons and the other one has its electrons,

681
00:31:15,920 --> 00:31:19,040
Speaker 1: and electrons just stay in there atom. They have a

682
00:31:19,040 --> 00:31:21,800
Speaker 1: little localized little neighborhood that they hang out in. But

683
00:31:21,880 --> 00:31:24,600
Speaker 1: in a conductor, the electrons flow freely, like they don't

684
00:31:24,640 --> 00:31:27,320
Speaker 1: necessarily have an assignment. They don't have like a home address.

685
00:31:27,360 --> 00:31:30,120
Speaker 1: They just sort of like move around between atoms. It

686
00:31:30,120 --> 00:31:32,360
Speaker 1: doesn't take much energy to go from one atom to

687
00:31:32,400 --> 00:31:34,480
Speaker 1: the next. There's no barrier there.

688
00:31:34,520 --> 00:31:36,880
Speaker 2: It insulates. You can't conduct electricity there.

689
00:31:37,000 --> 00:31:39,840
Speaker 1: Yeah, So insulators electrons can't jump between atoms, and a

690
00:31:39,840 --> 00:31:43,840
Speaker 1: conductor electrons just flow very easily between atoms. Now, in

691
00:31:43,880 --> 00:31:47,320
Speaker 1: a semiconductor has both, right, it has there's a flow

692
00:31:47,440 --> 00:31:49,320
Speaker 1: zone and a no flow zone. So if you have

693
00:31:49,480 --> 00:31:53,200
Speaker 1: enough energy then you can get up into this conduction

694
00:31:53,320 --> 00:31:55,600
Speaker 1: band where you can like float around between the atoms.

695
00:31:55,600 --> 00:32:00,240
Speaker 1: So high energy electrons can jump between them, but lowergy

696
00:32:00,240 --> 00:32:02,840
Speaker 1: electrons are sort of stuck in their atom. So there's

697
00:32:02,880 --> 00:32:04,560
Speaker 1: like the cool kids that are running all over the

698
00:32:04,560 --> 00:32:06,920
Speaker 1: neighborhood and then the ones where their parents tell them

699
00:32:06,960 --> 00:32:07,680
Speaker 1: they have to stay home.

700
00:32:07,680 --> 00:32:08,480
Speaker 2: They're all mixed together.

701
00:32:08,600 --> 00:32:11,280
Speaker 1: Yeah, there's two different kinds, and so based on how

702
00:32:11,320 --> 00:32:12,960
Speaker 1: much energy you have, and so that's what we call

703
00:32:13,040 --> 00:32:16,200
Speaker 1: this band gap. There's this energy gap if you're above

704
00:32:16,200 --> 00:32:18,960
Speaker 1: a certain energy that you can move around and below

705
00:32:19,000 --> 00:32:21,760
Speaker 1: that you can't move around. So that's what a semiconductor is.

706
00:32:21,800 --> 00:32:24,960
Speaker 1: And it's fascinating because it has this band gap. And

707
00:32:25,000 --> 00:32:26,920
Speaker 1: as you said, if you excite the electrons, you can

708
00:32:26,920 --> 00:32:29,760
Speaker 1: turn it into a conductor. But some of the electrons

709
00:32:29,920 --> 00:32:32,320
Speaker 1: they're low enough energy then they're an insulator. So you

710
00:32:32,360 --> 00:32:35,400
Speaker 1: get this sort of fine grain control about the electrical flow,

711
00:32:35,440 --> 00:32:37,680
Speaker 1: which is what makes it good for building circuits and

712
00:32:37,680 --> 00:32:38,480
Speaker 1: all sorts of stuff.

713
00:32:38,480 --> 00:32:41,800
Speaker 2: But it's not a question of the energy of the electrons, right,

714
00:32:41,840 --> 00:32:43,880
Speaker 2: It's more of a question of the kind of the

715
00:32:44,000 --> 00:32:45,640
Speaker 2: energy of the medium of the material.

716
00:32:45,760 --> 00:32:49,080
Speaker 1: Yeah, the material determines sort of this structure. Right, Different

717
00:32:49,200 --> 00:32:52,640
Speaker 1: kinds of semiconductors have different size band gaps, but that

718
00:32:52,720 --> 00:32:54,800
Speaker 1: band gap is the energy of the electrons that we're

719
00:32:54,800 --> 00:32:57,480
Speaker 1: talking about. And you can build all sorts of different

720
00:32:57,520 --> 00:33:01,080
Speaker 1: kinds of semic conductors, and you can build conductors based

721
00:33:01,120 --> 00:33:04,160
Speaker 1: on what material you use, like a gallium, is it

722
00:33:04,240 --> 00:33:06,880
Speaker 1: silicon is it some combination of these two. You can

723
00:33:06,880 --> 00:33:10,240
Speaker 1: build semiconductors that have a bunch of extra electrons in them,

724
00:33:10,440 --> 00:33:12,440
Speaker 1: so that it's called P type, like there's a bunch

725
00:33:12,480 --> 00:33:16,080
Speaker 1: of extra electrons floating around. Or there's semiconductors that are

726
00:33:16,120 --> 00:33:19,400
Speaker 1: called N types that have like empty holes where electrons

727
00:33:19,400 --> 00:33:19,920
Speaker 1: should go.

728
00:33:20,480 --> 00:33:23,640
Speaker 2: Yeah, So they're both semiconductors, and they're both of the

729
00:33:23,840 --> 00:33:26,040
Speaker 2: usually mean ad a silicon, right, with some sort of

730
00:33:26,040 --> 00:33:27,800
Speaker 2: metal kind of infused in it.

731
00:33:27,960 --> 00:33:30,160
Speaker 1: Yeah, And so you often start with silicon and then

732
00:33:30,200 --> 00:33:32,840
Speaker 1: you add little bits of other stuff to make different kinds.

733
00:33:33,200 --> 00:33:36,280
Speaker 1: And a diode is just an N type semiconductor right

734
00:33:36,320 --> 00:33:39,080
Speaker 1: next to a P type semiconductor. And what this means

735
00:33:39,160 --> 00:33:41,480
Speaker 1: is very simple. It just means the electricity can flow

736
00:33:41,520 --> 00:33:44,200
Speaker 1: in one direction. That's what a diode does. So the

737
00:33:44,240 --> 00:33:46,360
Speaker 1: P type has a bunch of electrons and the N

738
00:33:46,440 --> 00:33:48,560
Speaker 1: type has a bunch of holes for those electrons to

739
00:33:48,600 --> 00:33:52,320
Speaker 1: fall into. So the P type one has electrons floating

740
00:33:52,320 --> 00:33:54,880
Speaker 1: above this band gap. They can move around, et cetera,

741
00:33:54,920 --> 00:33:57,280
Speaker 1: et cetera. When you put a current over it, they

742
00:33:57,320 --> 00:34:01,880
Speaker 1: just fall into the holes, and electrons jumping from high

743
00:34:02,040 --> 00:34:05,840
Speaker 1: energy states to low energy states is how you emit energy.

744
00:34:05,880 --> 00:34:08,680
Speaker 1: So when they do that, they release photons. So a

745
00:34:08,760 --> 00:34:11,480
Speaker 1: diode is just P type and N type stuck together,

746
00:34:11,800 --> 00:34:14,279
Speaker 1: and a light emitting diode is one where when the

747
00:34:14,320 --> 00:34:16,879
Speaker 1: electrons fall in they emit visible light.

748
00:34:17,840 --> 00:34:19,840
Speaker 2: And it has to be a special kind of material

749
00:34:20,160 --> 00:34:23,040
Speaker 2: or is it still just silicon with some kind of

750
00:34:23,040 --> 00:34:23,440
Speaker 2: metal in it.

751
00:34:23,560 --> 00:34:25,200
Speaker 1: It has to be a special kind of material to

752
00:34:25,239 --> 00:34:27,879
Speaker 1: get the right color light. And so that's really the key,

753
00:34:27,960 --> 00:34:31,920
Speaker 1: that's the core physics for why blue LEDs were so fascinating.

754
00:34:32,200 --> 00:34:35,400
Speaker 1: The first LED's people invented, this gap was kind of small,

755
00:34:35,520 --> 00:34:37,080
Speaker 1: sort of hard to make it work, and so when

756
00:34:37,080 --> 00:34:39,439
Speaker 1: they fell from P type to N type, they didn't

757
00:34:39,480 --> 00:34:42,440
Speaker 1: have that much energy, and they emitted mostly in the infrared.

758
00:34:42,600 --> 00:34:46,040
Speaker 1: And for example, the LED that's in your remote control,

759
00:34:46,080 --> 00:34:48,759
Speaker 1: the one that controls your TV, you don't see light

760
00:34:48,840 --> 00:34:51,120
Speaker 1: coming out of the top of the remote control because

761
00:34:51,120 --> 00:34:53,000
Speaker 1: it comes out in a wavelength you can't see. It

762
00:34:53,000 --> 00:34:55,719
Speaker 1: comes out as infrared light to talk to your TV,

763
00:34:55,840 --> 00:34:58,080
Speaker 1: but there's an infrared LED at the top of your

764
00:34:58,080 --> 00:35:00,960
Speaker 1: remote control. Those are the first ones they're invented. It's

765
00:35:01,000 --> 00:35:03,640
Speaker 1: actually back in the sixties that they first came out

766
00:35:03,640 --> 00:35:07,239
Speaker 1: with infrared LEDs. And then the challenge was coming up

767
00:35:07,239 --> 00:35:10,319
Speaker 1: with different kinds of material to negotiate this like P

768
00:35:10,560 --> 00:35:13,800
Speaker 1: type N type difference. So you've got a larger gap,

769
00:35:13,960 --> 00:35:16,799
Speaker 1: so you have more energy when they fell, so you

770
00:35:16,800 --> 00:35:19,000
Speaker 1: have more energy in the photons so they could be

771
00:35:19,080 --> 00:35:19,640
Speaker 1: visible light.

772
00:35:19,800 --> 00:35:22,520
Speaker 2: Oh, so it's all about the difference between the P

773
00:35:22,719 --> 00:35:25,600
Speaker 2: and the N types of materials. Yes, okay, so it

774
00:35:25,680 --> 00:35:27,520
Speaker 2: sort of depends more on the N type and on

775
00:35:27,600 --> 00:35:28,479
Speaker 2: the size of the hole.

776
00:35:28,600 --> 00:35:30,240
Speaker 1: Now the hole is just a hole for an electron.

777
00:35:30,320 --> 00:35:33,040
Speaker 1: It depends on the gap between the P type and

778
00:35:33,080 --> 00:35:35,120
Speaker 1: the end type. So you're right, it depends on the

779
00:35:35,160 --> 00:35:37,759
Speaker 1: type of material and the size of this gap. And

780
00:35:37,760 --> 00:35:39,520
Speaker 1: you're putting this P type and this ND type next

781
00:35:39,560 --> 00:35:42,120
Speaker 1: to each other, and it's basically how far they fall,

782
00:35:42,360 --> 00:35:44,160
Speaker 1: Like are they just stepping down from the curb and

783
00:35:44,160 --> 00:35:45,719
Speaker 1: they go oop and they just give off a little

784
00:35:45,719 --> 00:35:48,160
Speaker 1: bit of light. Or are they jumping down Niagara Falls

785
00:35:48,160 --> 00:35:50,319
Speaker 1: and screaming all the way down and giving off a

786
00:35:50,360 --> 00:35:51,080
Speaker 1: lot of energy?

787
00:35:51,239 --> 00:35:53,320
Speaker 2: Oh, I see the electrons go from the P type

788
00:35:53,440 --> 00:35:56,280
Speaker 2: to the N type. They jump, Yeah, I see, Yeah,

789
00:35:56,400 --> 00:35:58,279
Speaker 2: they jump where they fall. You know, depending on whether

790
00:35:58,280 --> 00:36:03,080
Speaker 2: you believe the electrons can make decisions, they're pushed or

791
00:36:03,120 --> 00:36:04,760
Speaker 2: pull They're more like pulled, right.

792
00:36:04,719 --> 00:36:07,479
Speaker 1: Yeah, they're more like pulled. And so basically an LED

793
00:36:07,640 --> 00:36:09,240
Speaker 1: is a bunch of electrons screaming.

794
00:36:09,280 --> 00:36:13,680
Speaker 2: So great, next time you look at your phone, your

795
00:36:13,680 --> 00:36:17,879
Speaker 2: phone is screaming the area photons at you every time. Yeah,

796
00:36:17,920 --> 00:36:20,600
Speaker 2: it's not just your brain that's screaming from your Twitter feed.

797
00:36:20,719 --> 00:36:22,920
Speaker 1: And the thing that's amazing about this is that it's

798
00:36:22,960 --> 00:36:26,080
Speaker 1: solid state, right. Nothing is moving here. You don't have

799
00:36:26,160 --> 00:36:28,560
Speaker 1: gas that's bouncing around, you don't have metal that's heating

800
00:36:28,640 --> 00:36:31,160
Speaker 1: up and cooling down. It's just fixed and it's just

801
00:36:31,200 --> 00:36:33,520
Speaker 1: like an electrical circuit, and that makes it last for

802
00:36:33,560 --> 00:36:36,759
Speaker 1: a very very long time. It lasts for like one

803
00:36:36,840 --> 00:36:39,480
Speaker 1: hundred thousand hours before it finally breaks.

804
00:36:39,480 --> 00:36:42,000
Speaker 2: Electrons can scream for as long as you need them to.

805
00:36:42,080 --> 00:36:42,840
Speaker 2: That's what you're saying.

806
00:36:44,280 --> 00:36:47,279
Speaker 1: That's right. Unfortunately, the lifespan of electron it is very,

807
00:36:47,360 --> 00:36:50,160
Speaker 1: very long. It's doomed to a long life of falling

808
00:36:50,200 --> 00:36:50,919
Speaker 1: down this gap.

809
00:36:51,040 --> 00:36:53,080
Speaker 2: I guess my question is what keeps the light going? Like,

810
00:36:53,120 --> 00:36:55,040
Speaker 2: once it falls into the hole, wouldn't it just stay

811
00:36:55,080 --> 00:36:55,520
Speaker 2: in the hole?

812
00:36:55,760 --> 00:36:56,960
Speaker 1: Yeah, it does, wouldn't it.

813
00:36:57,000 --> 00:36:57,800
Speaker 2: Fill up all the holes?

814
00:36:57,800 --> 00:36:59,840
Speaker 1: Well? You have a current, right, and so you're pulling

815
00:36:59,880 --> 00:37:02,080
Speaker 1: the electrons out of the end type. So the whole

816
00:37:02,080 --> 00:37:04,360
Speaker 1: thing is connected to a current. Imagine like a battery

817
00:37:04,480 --> 00:37:08,320
Speaker 1: powering the led. It's sending fresh electrons into the p

818
00:37:08,520 --> 00:37:11,080
Speaker 1: type and pulling the electrons out of the end time.

819
00:37:11,320 --> 00:37:12,520
Speaker 1: So the whole thing is a circuit.

820
00:37:12,600 --> 00:37:15,680
Speaker 2: It is like a waterfall. It's like a continual waterfall exactly.

821
00:37:15,760 --> 00:37:17,760
Speaker 1: It's just like a waterfall. You're pumping on one side

822
00:37:18,040 --> 00:37:19,839
Speaker 1: and then they scream on their way down. It's more

823
00:37:19,920 --> 00:37:21,480
Speaker 1: like a roller coaster because of the screaming.

824
00:37:22,280 --> 00:37:26,319
Speaker 2: I see, Yeah, that's right. Then they go bent down

825
00:37:26,320 --> 00:37:28,680
Speaker 2: and then the cart gets pulled over and then up

826
00:37:28,719 --> 00:37:31,160
Speaker 2: the wrap again and then down and then screen. Let's

827
00:37:31,160 --> 00:37:33,680
Speaker 2: not think of it as electrons suffering, but electrons is

828
00:37:33,680 --> 00:37:34,200
Speaker 2: having a lot of.

829
00:37:34,200 --> 00:37:36,120
Speaker 1: Fun, that's right. And you know you might wonder why

830
00:37:36,120 --> 00:37:38,320
Speaker 1: do people go on roller coasters because they scream the

831
00:37:38,360 --> 00:37:40,440
Speaker 1: whole time? Well, I guess they like to scream, and

832
00:37:40,480 --> 00:37:44,600
Speaker 1: so we can imagine that also electrons are enjoying this ride.

833
00:37:44,680 --> 00:37:45,239
Speaker 2: That's where you go.

834
00:37:45,440 --> 00:37:48,279
Speaker 1: There's thrill seekers, and they seem to be happy to

835
00:37:48,320 --> 00:37:50,680
Speaker 1: do it. Because LED's last for one hundred thousand hours

836
00:37:51,000 --> 00:37:54,160
Speaker 1: and it's very very efficient. Most of the energy that

837
00:37:54,200 --> 00:37:57,959
Speaker 1: you're sending into this circuit actually goes into emitting light. Yeah,

838
00:37:57,960 --> 00:38:00,400
Speaker 1: it's like more than fifty percent of the energy.

839
00:38:00,400 --> 00:38:03,560
Speaker 2: Wow, that's ten times, ten times more efficient than the

840
00:38:03,840 --> 00:38:04,560
Speaker 2: incandescent bule.

841
00:38:04,719 --> 00:38:08,000
Speaker 1: Yeah, ten times more efficient. And the challenge is in

842
00:38:08,200 --> 00:38:11,040
Speaker 1: finding the right gaps you get the right energy levels,

843
00:38:11,040 --> 00:38:13,440
Speaker 1: so you get the right colors. And so the first

844
00:38:13,440 --> 00:38:16,120
Speaker 1: thing was infrared, and then you know, infrared is the

845
00:38:16,160 --> 00:38:19,560
Speaker 1: lowest frequency, the longest wavelength, and then they figured out

846
00:38:19,640 --> 00:38:21,799
Speaker 1: ways to make them longer so they were visible and

847
00:38:21,840 --> 00:38:24,560
Speaker 1: then longer so you got red, you got green, And

848
00:38:24,600 --> 00:38:26,480
Speaker 1: then the challenge was blue LEDs.

849
00:38:26,960 --> 00:38:27,320
Speaker 4: Dumb.

850
00:38:28,360 --> 00:38:31,520
Speaker 2: All right, let's get into the amazing discovery that was

851
00:38:31,600 --> 00:38:34,840
Speaker 2: discovering blue LEDs and why it got the Nobel Prize.

852
00:38:34,840 --> 00:38:36,840
Speaker 2: But first, let's take a quick break.

853
00:38:41,040 --> 00:38:42,840
Speaker 1: When you pop a piece of cheese into your mouth

854
00:38:42,920 --> 00:38:46,080
Speaker 1: or enjoy a rich spoonful of greeky yogurt, you're probably

855
00:38:46,120 --> 00:38:50,160
Speaker 1: not thinking about the environmental impact of each and every bite,

856
00:38:50,200 --> 00:38:52,800
Speaker 1: But the people in the dairy industry are. US Dairy

857
00:38:52,840 --> 00:38:57,120
Speaker 1: has set themselves some ambitious sustainability goals, including being greenhouse

858
00:38:57,200 --> 00:38:59,680
Speaker 1: gas neutral by twenty to fifty. That's why they're working

859
00:38:59,719 --> 00:39:02,160
Speaker 1: hard every day to find new ways to reduce waste,

860
00:39:02,200 --> 00:39:06,399
Speaker 1: conserve natural resources, and drive down greenhouse gas emissions. Take water,

861
00:39:06,480 --> 00:39:09,560
Speaker 1: for example, most dairy farms reuse water up to four

862
00:39:09,600 --> 00:39:13,080
Speaker 1: times the same water cools the milk, cleans equipment, washes

863
00:39:13,120 --> 00:39:15,920
Speaker 1: the barn, and irrigates the crops. How is US dairy

864
00:39:15,920 --> 00:39:19,680
Speaker 1: tackling greenhouse gases? Many farms use anaerobic digestors that turn

865
00:39:19,719 --> 00:39:23,640
Speaker 1: the methane from maneuver into renewable energy that can power farms, towns,

866
00:39:23,640 --> 00:39:25,759
Speaker 1: and electric cars. So the next time you grab a

867
00:39:25,760 --> 00:39:27,799
Speaker 1: slice of pizza or lick an ice cream cone, know

868
00:39:27,840 --> 00:39:30,560
Speaker 1: that dairy farmers and processors around the country are using

869
00:39:30,560 --> 00:39:34,080
Speaker 1: the latest practices and innovations to provide the nutrient dense

870
00:39:34,200 --> 00:39:36,919
Speaker 1: dairy products we love with less of an impact visit

871
00:39:37,000 --> 00:39:39,799
Speaker 1: usdairy dot com slash sustainability to learn more.

872
00:39:40,440 --> 00:39:44,000
Speaker 3: Hi, I'm David Eagleman from the podcast Inner Cosmos, which

873
00:39:44,040 --> 00:39:47,319
Speaker 3: recently hit the number one science podcast in America. I

874
00:39:47,360 --> 00:39:51,200
Speaker 3: mean neuroscientists at Stanford, and I've spent my career exploring

875
00:39:51,280 --> 00:39:54,279
Speaker 3: the three pound universe in our heads. We're looking at

876
00:39:54,280 --> 00:39:57,520
Speaker 3: a whole new series of episodes this season to understand

877
00:39:57,640 --> 00:40:01,359
Speaker 3: why and how our lives looked way they do. Why

878
00:40:01,360 --> 00:40:04,560
Speaker 3: does your memory drift so much? Why is it so

879
00:40:04,800 --> 00:40:08,480
Speaker 3: hard to keep a secret, When should you not trust

880
00:40:08,560 --> 00:40:13,040
Speaker 3: your intuition? Why do brains so easily fall for magic tricks?

881
00:40:13,280 --> 00:40:16,719
Speaker 3: And why do they love conspiracy theories? I'm hitting these

882
00:40:16,840 --> 00:40:20,600
Speaker 3: questions and hundreds more because the more we know about

883
00:40:20,640 --> 00:40:24,560
Speaker 3: what's running under the hood, better we can steer our lives.

884
00:40:25,200 --> 00:40:28,560
Speaker 3: Join me weekly to explore the relationship between your brain

885
00:40:28,680 --> 00:40:33,279
Speaker 3: and your life by digging into unexpected questions. Listen to

886
00:40:33,280 --> 00:40:37,319
Speaker 3: Inner Cosmos with David Eagleman on the iHeartRadio app, Apple Podcasts,

887
00:40:37,440 --> 00:40:39,160
Speaker 3: or wherever you get your podcasts.

888
00:40:41,000 --> 00:40:44,160
Speaker 7: Parents, are you looking for a screen free, engaging way

889
00:40:44,160 --> 00:40:46,200
Speaker 7: to teach your kids the Bible? One that's easy to

890
00:40:46,280 --> 00:40:50,719
Speaker 7: understand and enjoyable for multiple ages. Kids Bible Stories Podcast

891
00:40:50,760 --> 00:40:53,680
Speaker 7: is here to help. I created this for my own children,

892
00:40:53,760 --> 00:40:57,040
Speaker 7: and it's now a favorite among thousands of families. Kids

893
00:40:57,160 --> 00:41:00,560
Speaker 7: love the vivid imagery, scriptures, and sound effects, while parents

894
00:41:00,600 --> 00:41:04,400
Speaker 7: appreciate the apply section for meaningful conversations. We have hundreds

895
00:41:04,440 --> 00:41:07,680
Speaker 7: and hundreds of beautiful episodes that bring the Bible to

896
00:41:07,719 --> 00:41:11,400
Speaker 7: life when you simply press play. It's a sound and

897
00:41:11,520 --> 00:41:15,200
Speaker 7: practical resource that walks alongside you as you teach your kids.

898
00:41:15,800 --> 00:41:18,759
Speaker 7: We want kids to see how incredible God's word is

899
00:41:19,000 --> 00:41:23,280
Speaker 7: in an engaging and memorable way with Kids Bible Stories Podcast.

900
00:41:24,520 --> 00:41:27,360
Speaker 7: Listen to Kids Bible Stories Podcast on the iHeartRadio app,

901
00:41:27,400 --> 00:41:30,319
Speaker 7: Apple Podcasts, or wherever you get your podcasts.

902
00:41:40,120 --> 00:41:43,040
Speaker 2: All right, Daniel, somebody got a Noble prize for discovering

903
00:41:43,440 --> 00:41:46,319
Speaker 2: the blue led. So what's so special about blue led?

904
00:41:46,520 --> 00:41:47,759
Speaker 1: I like the way you make it sound like they

905
00:41:47,760 --> 00:41:50,279
Speaker 1: discovered a blue led. Like, well, I was sweeping up

906
00:41:50,360 --> 00:41:52,080
Speaker 1: my lab and I found this thing on the ground.

907
00:41:52,080 --> 00:41:53,359
Speaker 1: Oh my god, it's a blue led.

908
00:41:53,800 --> 00:41:55,960
Speaker 2: Right, It's just what I was looking for.

909
00:41:56,160 --> 00:41:58,960
Speaker 1: Because that's how we discover particles, right, you know, we're like,

910
00:41:58,960 --> 00:42:01,040
Speaker 1: oh my gosh, look I found a tau particle and

911
00:42:01,080 --> 00:42:03,640
Speaker 1: now I get a Nobel Prize. I didn't like design

912
00:42:03,680 --> 00:42:05,719
Speaker 1: it or engineer it or invent it.

913
00:42:05,840 --> 00:42:09,400
Speaker 2: Right, it should be more like somebody designed blue d invented.

914
00:42:09,600 --> 00:42:12,040
Speaker 1: Yeah, somebody invented the blue led which is sort of

915
00:42:12,120 --> 00:42:13,240
Speaker 1: awesome and impressive.

916
00:42:13,280 --> 00:42:15,359
Speaker 2: So we couldn't just take a white LED and put

917
00:42:15,360 --> 00:42:16,359
Speaker 2: a blue filter on it.

918
00:42:16,400 --> 00:42:19,120
Speaker 1: Well, that's the thing. You can't make white LEDs without blue.

919
00:42:19,320 --> 00:42:22,560
Speaker 1: Right before we had blue LEDs, we had green and

920
00:42:22,600 --> 00:42:25,440
Speaker 1: we had red, and so you couldn't make white LEDs.

921
00:42:25,920 --> 00:42:29,240
Speaker 1: That's why blue LEDs are so important because with blue

922
00:42:29,760 --> 00:42:32,000
Speaker 1: you can make the combination you need to make white.

923
00:42:32,120 --> 00:42:36,040
Speaker 1: And nobody wants in their reading light a green light

924
00:42:36,200 --> 00:42:38,319
Speaker 1: or a red light. You want a white LED and

925
00:42:38,360 --> 00:42:39,920
Speaker 1: you couldn't make white without blue.

926
00:42:40,000 --> 00:42:42,279
Speaker 2: Oh, you need the blue. You need the blue to

927
00:42:42,320 --> 00:42:43,400
Speaker 2: make the blue.

928
00:42:43,160 --> 00:42:46,080
Speaker 1: To make the white. And that's why LEDs have exploded

929
00:42:46,160 --> 00:42:49,279
Speaker 1: in applications everywhere because now they can make essentially any

930
00:42:49,280 --> 00:42:51,320
Speaker 1: color because we have the missing blue.

931
00:42:51,360 --> 00:42:53,640
Speaker 2: Cool. So tell me what was so hard about it

932
00:42:53,680 --> 00:42:55,120
Speaker 2: and what's the physics behind it?

933
00:42:55,200 --> 00:42:57,040
Speaker 1: Yeah, and so it's sort of an interesting question, like

934
00:42:57,080 --> 00:42:59,759
Speaker 1: it really was an engineering puzzle, Like you just needed

935
00:42:59,760 --> 00:43:01,840
Speaker 1: to get the right material. You needed to get the

936
00:43:01,960 --> 00:43:04,680
Speaker 1: right material with the right thickness and configure it all

937
00:43:04,719 --> 00:43:07,759
Speaker 1: correctly to get blue. And it's tricky to get this

938
00:43:07,920 --> 00:43:10,879
Speaker 1: gap to be extra extra large, large enough to make

939
00:43:10,960 --> 00:43:13,400
Speaker 1: so that when the electrons go down that roller coaster

940
00:43:13,440 --> 00:43:16,040
Speaker 1: they scream for long enough to give you a blue photon.

941
00:43:16,640 --> 00:43:18,360
Speaker 1: And you know, it turns out to be something of

942
00:43:18,400 --> 00:43:22,040
Speaker 1: a condensed matter and solid state engineering problem, and a

943
00:43:22,040 --> 00:43:24,239
Speaker 1: couple of Japanese people figured it out. You need some

944
00:43:24,560 --> 00:43:28,520
Speaker 1: mixture of gallium nitride with other silicon substrates and then

945
00:43:28,560 --> 00:43:29,919
Speaker 1: you can get this blue led.

946
00:43:30,120 --> 00:43:32,080
Speaker 2: But I guess why was it so hard? Like when

947
00:43:32,120 --> 00:43:35,080
Speaker 2: you try to make electrons jump that much, it would

948
00:43:35,080 --> 00:43:37,960
Speaker 2: burn out or they just wouldn't do it, or you know,

949
00:43:38,000 --> 00:43:41,160
Speaker 2: they wouldn't scream as much as you wanted to. What

950
00:43:41,239 --> 00:43:42,919
Speaker 2: was the difficulty in getting this right?

951
00:43:43,200 --> 00:43:45,480
Speaker 1: It was just in finding one that would work. You know,

952
00:43:45,680 --> 00:43:47,920
Speaker 1: most things just didn't have this large enough gap, and

953
00:43:47,960 --> 00:43:50,680
Speaker 1: so it's just about finding a material that had this gap.

954
00:43:50,480 --> 00:43:51,520
Speaker 2: And that also worked.

955
00:43:51,640 --> 00:43:52,560
Speaker 1: Yeah, that also worked.

956
00:43:52,600 --> 00:43:54,120
Speaker 2: I mean you can make a gap, but it it

957
00:43:54,160 --> 00:43:55,440
Speaker 2: may not necessarily work.

958
00:43:55,320 --> 00:43:57,839
Speaker 1: Yeah, to get the electrons to flow across it. And

959
00:43:57,920 --> 00:44:00,879
Speaker 1: so we can't necessarily predict in advance something's going to work.

960
00:44:00,880 --> 00:44:02,440
Speaker 1: So they sort of had just had to search through

961
00:44:02,480 --> 00:44:04,480
Speaker 1: lots of different kinds of materials and try this and

962
00:44:04,520 --> 00:44:07,319
Speaker 1: try this, and have inside and inspiration and also just

963
00:44:07,360 --> 00:44:09,920
Speaker 1: some luck into making it work. And so that's why

964
00:44:10,000 --> 00:44:13,040
Speaker 1: I think it's interesting, like does this deserve a Physics

965
00:44:13,040 --> 00:44:17,120
Speaker 1: Nobel Prize, Like, there's no new principle discovered here. There's

966
00:44:17,160 --> 00:44:21,280
Speaker 1: no fundamental revelation of the nature of the universe or space,

967
00:44:21,360 --> 00:44:25,040
Speaker 1: time or history or whatever. It was an engineering step forward,

968
00:44:25,080 --> 00:44:28,200
Speaker 1: which hey, deep respect for the engineering step forward. But

969
00:44:28,360 --> 00:44:31,240
Speaker 1: I think the reason it got the Physics Nobel Prize

970
00:44:31,400 --> 00:44:34,560
Speaker 1: is because of the huge impact on society.

971
00:44:34,680 --> 00:44:37,360
Speaker 2: Really, you guys look down on things that are useful.

972
00:44:38,080 --> 00:44:42,240
Speaker 1: You're like, well, you know, I think the original Nobel

973
00:44:42,280 --> 00:44:45,360
Speaker 1: Prize was supposed to be about things that shape society,

974
00:44:45,920 --> 00:44:49,280
Speaker 1: and so I think Alfred Nobel would probably be pretty pleased.

975
00:44:49,719 --> 00:44:52,440
Speaker 1: But more recently, a lot of these prizes have been

976
00:44:52,440 --> 00:44:56,360
Speaker 1: awarded for like deep but maybe impractical discoveries about the

977
00:44:56,440 --> 00:44:58,719
Speaker 1: nature of neutrinos or gravitational with.

978
00:44:59,040 --> 00:45:02,520
Speaker 2: Oh, that's right, Nobel was an inventor, right, he wasn't

979
00:45:02,560 --> 00:45:03,200
Speaker 2: a physicist.

980
00:45:03,239 --> 00:45:06,560
Speaker 6: He was an engineer, exactly. You guys have co opted

981
00:45:06,560 --> 00:45:09,040
Speaker 6: our prize exactly. So in some sense, this is like

982
00:45:09,080 --> 00:45:12,799
Speaker 6: a return to Nobel's roots, Right, is recognizing something of

983
00:45:12,880 --> 00:45:16,640
Speaker 6: great import to society because it has had a huge impact. Right,

984
00:45:16,880 --> 00:45:20,400
Speaker 6: it was like the missing piece. There's nothing weird physically

985
00:45:20,440 --> 00:45:22,880
Speaker 6: about blue. It's just sort of the highest frequency and

986
00:45:22,920 --> 00:45:25,000
Speaker 6: therefore the last for us to put together.

987
00:45:25,120 --> 00:45:26,799
Speaker 2: Oh, I said, so do you think somebody should have

988
00:45:26,880 --> 00:45:30,440
Speaker 2: gotten a prize, a Nobel prize for discovering the Higgs boson?

989
00:45:30,680 --> 00:45:32,960
Speaker 2: Because the people who wanted want it for coming up

990
00:45:33,000 --> 00:45:34,600
Speaker 2: sort of with the Higgs boson, But the people who

991
00:45:34,600 --> 00:45:37,000
Speaker 2: discovered it it was mostly just sort of engineering. Right.

992
00:45:37,640 --> 00:45:39,960
Speaker 1: You just described my whole field as mostly sort of

993
00:45:40,040 --> 00:45:42,960
Speaker 1: just engineering, which is so many at fastening the angles

994
00:45:42,960 --> 00:45:44,680
Speaker 1: because I think you meant that as a diss but

995
00:45:44,760 --> 00:45:46,160
Speaker 1: you described it as engineering.

996
00:45:46,320 --> 00:45:50,000
Speaker 2: So no, I hold engineering that the highest esteemed I know.

997
00:45:50,400 --> 00:45:52,480
Speaker 2: I was actually trying to pay you a compliments.

998
00:45:52,640 --> 00:45:54,880
Speaker 1: You were trying to elevate our field by describing as engineering.

999
00:45:54,960 --> 00:45:55,160
Speaker 2: DS.

1000
00:45:55,239 --> 00:45:56,080
Speaker 1: I appreciate that.

1001
00:45:56,000 --> 00:45:57,440
Speaker 2: It's aspiring to be useful.

1002
00:45:58,040 --> 00:45:59,880
Speaker 1: Well, I'm not even sure how useful it is. Just

1003
00:46:00,040 --> 00:46:03,239
Speaker 1: over the Higgs boson. But I think the great innovation

1004
00:46:03,440 --> 00:46:07,080
Speaker 1: there was definitely in having the idea and finding it.

1005
00:46:07,239 --> 00:46:08,960
Speaker 1: I don't know how many big steps forward. I mean,

1006
00:46:09,000 --> 00:46:12,799
Speaker 1: it's a huge effort and technological achievement, but I don't

1007
00:46:12,880 --> 00:46:16,200
Speaker 1: know that we necessarily created anything new. We certainly didn't

1008
00:46:16,440 --> 00:46:19,919
Speaker 1: make anything as fascinating and impactful as the blue led

1009
00:46:20,400 --> 00:46:22,400
Speaker 1: We just sort of confirmed an idea that it was

1010
00:46:22,440 --> 00:46:25,360
Speaker 1: in people's minds. So we revealed something about the nature

1011
00:46:25,360 --> 00:46:27,520
Speaker 1: of the universe, but something that sort of had been

1012
00:46:27,560 --> 00:46:29,360
Speaker 1: suspected to exist already.

1013
00:46:29,920 --> 00:46:32,480
Speaker 2: But okay, so back to the blue led that's important

1014
00:46:32,480 --> 00:46:35,160
Speaker 2: because now you have blue, and with red and green

1015
00:46:35,360 --> 00:46:37,279
Speaker 2: you can make white light, so you can make any

1016
00:46:37,360 --> 00:46:39,759
Speaker 2: kind of color. Yes, now that you have blue LEDs.

1017
00:46:39,640 --> 00:46:42,520
Speaker 1: Yes, exactly. And so these guys invented it in the

1018
00:46:42,600 --> 00:46:44,719
Speaker 1: nineties and then they won the Nobel Prize for it

1019
00:46:44,760 --> 00:46:47,600
Speaker 1: a few years later. That's how LED's work, and that's

1020
00:46:47,600 --> 00:46:48,640
Speaker 1: why there's on boardant.

1021
00:46:48,440 --> 00:46:50,279
Speaker 2: So that the people who discovered the red LEDs and

1022
00:46:50,320 --> 00:46:52,719
Speaker 2: the green LEDs also get a prize, or only the

1023
00:46:53,120 --> 00:46:57,120
Speaker 2: one who waited till the end and procrastinated to discover

1024
00:46:57,440 --> 00:46:59,280
Speaker 2: the missing color get the prize.

1025
00:47:00,040 --> 00:47:02,319
Speaker 1: I feel like you have another horse in this race here,

1026
00:47:03,360 --> 00:47:04,680
Speaker 1: your pro procrastination.

1027
00:47:04,800 --> 00:47:06,680
Speaker 2: Yeah, I've built a whole career on it. Anyway.

1028
00:47:06,719 --> 00:47:08,920
Speaker 1: Yeah, the lesson here is weight and just sort of

1029
00:47:08,920 --> 00:47:10,799
Speaker 1: put the period at the end of the sentence and

1030
00:47:10,840 --> 00:47:13,319
Speaker 1: you'll get the prize for everybody else's work.

1031
00:47:13,719 --> 00:47:15,839
Speaker 2: Yeah, there you go. But in a way, it's true, right,

1032
00:47:15,880 --> 00:47:17,680
Speaker 2: like the person who will discovered the red and the

1033
00:47:17,680 --> 00:47:20,000
Speaker 2: green one didn't get a prize, but somehow, like you know,

1034
00:47:20,120 --> 00:47:23,440
Speaker 2: completing the triangle to get white light made a bigger splash.

1035
00:47:23,480 --> 00:47:25,640
Speaker 1: Yeah, the person who puts the capstone on the top

1036
00:47:25,680 --> 00:47:28,839
Speaker 1: of the pyramid, right, is the one that claims the prize, right.

1037
00:47:28,760 --> 00:47:30,799
Speaker 2: The one who discovers the mass particle is the one

1038
00:47:30,800 --> 00:47:33,160
Speaker 2: who But yeah, so now we can make white light

1039
00:47:33,200 --> 00:47:37,840
Speaker 2: with LEDs that is super efficient and also small, really small.

1040
00:47:37,920 --> 00:47:41,720
Speaker 2: Like maybe before you couldn't make incandescent bulbs small enough

1041
00:47:41,760 --> 00:47:45,040
Speaker 2: for you know, written at display kinds of screens, but

1042
00:47:45,120 --> 00:47:47,680
Speaker 2: now you can because LEDs, you can make them really

1043
00:47:47,719 --> 00:47:48,160
Speaker 2: really small.

1044
00:47:48,239 --> 00:47:51,319
Speaker 1: Yeah, because we can print sema conductors using these lithography

1045
00:47:51,360 --> 00:47:54,160
Speaker 1: techniques to be really really super tiny. And you know,

1046
00:47:54,239 --> 00:47:57,560
Speaker 1: we'd invented these techniques mostly so we can make transistors

1047
00:47:57,640 --> 00:48:00,880
Speaker 1: really really small, so we can make computer chips packed

1048
00:48:00,920 --> 00:48:02,600
Speaker 1: with all sorts of little circuits on them. But we

1049
00:48:02,600 --> 00:48:06,080
Speaker 1: can also use the same technology to make LEDs. And LEDs, remember,

1050
00:48:06,120 --> 00:48:09,440
Speaker 1: are not monochromatic. They're not like tiny little lasers. Right.

1051
00:48:09,680 --> 00:48:13,520
Speaker 1: Lasers shoot exactly one frequency or very very tight band

1052
00:48:13,600 --> 00:48:17,360
Speaker 1: or frequency because the photons come from one atomic step.

1053
00:48:17,840 --> 00:48:20,160
Speaker 1: Las are not quite like that. The light they emit

1054
00:48:20,239 --> 00:48:21,480
Speaker 1: is narrowly focused.

1055
00:48:21,480 --> 00:48:24,279
Speaker 2: It doesn't have just a single wave length or frequency.

1056
00:48:24,360 --> 00:48:27,040
Speaker 2: It's like it is a little bit like incandescent that

1057
00:48:27,120 --> 00:48:27,920
Speaker 2: it's kind of broad.

1058
00:48:28,120 --> 00:48:30,799
Speaker 1: Yeah. Yeah, they're broader than lasers, but not as broad

1059
00:48:30,800 --> 00:48:33,560
Speaker 1: as incandescent. So that's why there are specific color. But

1060
00:48:33,600 --> 00:48:35,920
Speaker 1: they're not like a really tight band like lasers.

1061
00:48:35,960 --> 00:48:38,520
Speaker 2: Okay, so then when I turn on the flashlight on

1062
00:48:38,560 --> 00:48:41,319
Speaker 2: my phone and I see this white light come off,

1063
00:48:41,360 --> 00:48:43,520
Speaker 2: and that helps me at night and get around at night,

1064
00:48:43,840 --> 00:48:47,000
Speaker 2: I'm actually seeing not a white LED, but like a

1065
00:48:47,000 --> 00:48:49,720
Speaker 2: whole bunch of red, blue, and green LEDs mixed together.

1066
00:48:49,800 --> 00:48:51,920
Speaker 1: That's right. And when you look on your screen and

1067
00:48:51,960 --> 00:48:54,560
Speaker 1: you see white for the blank page and the word

1068
00:48:54,560 --> 00:48:56,680
Speaker 1: document of the novel you've been writing for ten years,

1069
00:48:57,040 --> 00:49:00,000
Speaker 1: than what you're really seeing, are red, green, and blue blinking?

1070
00:49:00,040 --> 00:49:02,160
Speaker 2: Your failure actually blinking?

1071
00:49:02,520 --> 00:49:04,359
Speaker 1: But you know, that's what Newton discovered is that white

1072
00:49:04,440 --> 00:49:07,200
Speaker 1: light is actually just a mixture of colored lights. There's

1073
00:49:07,200 --> 00:49:10,440
Speaker 1: no difference. There is no white photon, there's no color

1074
00:49:10,520 --> 00:49:13,000
Speaker 1: in the spectrum that is white. White light is just

1075
00:49:13,040 --> 00:49:14,920
Speaker 1: a mixture of red, green, and blue.

1076
00:49:14,960 --> 00:49:15,240
Speaker 6: Wow.

1077
00:49:15,400 --> 00:49:20,879
Speaker 2: And so basically that increased our human level global efficiency

1078
00:49:20,960 --> 00:49:23,840
Speaker 2: for light by ten times. So now we can be

1079
00:49:23,960 --> 00:49:25,440
Speaker 2: a whole lot more eco friendly.

1080
00:49:25,520 --> 00:49:28,160
Speaker 1: Yeah, except probably just means we made a lot more bulbs,

1081
00:49:28,320 --> 00:49:30,279
Speaker 1: so probably using the same out of electricity, and now

1082
00:49:30,280 --> 00:49:31,520
Speaker 1: we're just lighting everything up.

1083
00:49:32,960 --> 00:49:35,080
Speaker 2: No, I changed all the light bulbs in my house

1084
00:49:35,120 --> 00:49:38,360
Speaker 2: for LEDs in boy, your power build drops like crazy.

1085
00:49:38,440 --> 00:49:40,680
Speaker 1: Yeah. Well do you appreciate it though? For working? Like

1086
00:49:40,719 --> 00:49:43,879
Speaker 1: when you're drawing something, do you like using natural light

1087
00:49:44,080 --> 00:49:46,640
Speaker 1: or incandescent light or LED light or does it not

1088
00:49:46,680 --> 00:49:48,839
Speaker 1: make any difference because you do everything at two am?

1089
00:49:49,520 --> 00:49:52,920
Speaker 2: Well, I draw everything on the computer, so it's all

1090
00:49:53,040 --> 00:49:57,279
Speaker 2: LED power, baby, you know, yeah, I guess so all right,

1091
00:49:57,360 --> 00:50:00,160
Speaker 2: Well that's pretty cool. I have a new respect for

1092
00:50:00,239 --> 00:50:03,000
Speaker 2: blue LEDs now and also a little respect for red

1093
00:50:03,040 --> 00:50:05,080
Speaker 2: and green LEDs you know, I feel like they got

1094
00:50:05,120 --> 00:50:06,800
Speaker 2: the short end of the colored triangle.

1095
00:50:06,840 --> 00:50:08,400
Speaker 1: They are singing the Nobel Blues.

1096
00:50:08,480 --> 00:50:10,400
Speaker 2: All right, but I think you know it points as

1097
00:50:10,480 --> 00:50:14,120
Speaker 2: to how even a small discovering physics or experimental physics

1098
00:50:14,239 --> 00:50:17,600
Speaker 2: can lead to basically a revolution in how we lead

1099
00:50:17,600 --> 00:50:20,600
Speaker 2: our lives and what kinds of devices we use every day.

1100
00:50:20,760 --> 00:50:22,960
Speaker 1: That's right. Engineering can change the world.

1101
00:50:23,120 --> 00:50:26,680
Speaker 2: What Yeah, can you guys replay that? Which is one

1102
00:50:26,680 --> 00:50:28,160
Speaker 2: more time? I just want to make sure that we

1103
00:50:28,360 --> 00:50:29,759
Speaker 2: heard it right? Can you replay it?

1104
00:50:29,880 --> 00:50:31,440
Speaker 1: Engineering can change the world.

1105
00:50:34,480 --> 00:50:37,120
Speaker 2: I'm going to download it, frame it, frame it on

1106
00:50:37,160 --> 00:50:38,160
Speaker 2: an LED frame.

1107
00:50:38,400 --> 00:50:39,800
Speaker 1: I should send you a little button. You can just

1108
00:50:39,800 --> 00:50:43,200
Speaker 1: press that and hear me say that you want.

1109
00:50:42,520 --> 00:50:45,560
Speaker 2: To hag into your phone and make it your ringtone tone?

1110
00:50:46,840 --> 00:50:49,520
Speaker 2: All right? Well, we hope you enjoyed that, and we

1111
00:50:49,560 --> 00:50:51,719
Speaker 2: hope you look at light in a whole different light.

1112
00:50:52,000 --> 00:51:02,560
Speaker 1: Thanks for tuning in, See you next time. Thanks for listening,

1113
00:51:02,560 --> 00:51:05,279
Speaker 1: and remember that Daniel and Jorge Explain the Universe is

1114
00:51:05,320 --> 00:51:09,560
Speaker 1: a production of iHeartRadio. For more podcasts from iHeart Radio,

1115
00:51:09,680 --> 00:51:14,000
Speaker 1: visit the iheartradiopapp, Apple Podcasts, or wherever you listen to

1116
00:51:14,080 --> 00:51:22,439
Speaker 1: your favorite shows. When you pop a piece of cheese

1117
00:51:22,480 --> 00:51:25,840
Speaker 1: into your mouth. You're probably not thinking about the environmental impact,

1118
00:51:26,080 --> 00:51:28,640
Speaker 1: but the people in the dairy industry are. That's why

1119
00:51:28,719 --> 00:51:31,200
Speaker 1: they're working hard every day to find new ways to

1120
00:51:31,239 --> 00:51:35,600
Speaker 1: reduce waste, conserve natural resources, and drive down greenhouse gas emissions.

1121
00:51:35,880 --> 00:51:40,080
Speaker 1: House US dairy tackling greenhouse gases. Many farms use anaerobic

1122
00:51:40,120 --> 00:51:43,880
Speaker 1: digestors to turn the methane from manure into renewable energy

1123
00:51:43,920 --> 00:51:47,480
Speaker 1: that can power farms, towns, and electric cars. Visit you

1124
00:51:47,560 --> 00:51:50,520
Speaker 1: as dairy dot COM's Last Sustainability to learn more.

1125
00:51:51,520 --> 00:51:55,080
Speaker 3: Hi, I'm David Eagleman from the podcast Inner Cosmos, which

1126
00:51:55,080 --> 00:51:58,080
Speaker 3: recently hit the number one science podcast in America. I

1127
00:51:58,160 --> 00:52:01,879
Speaker 3: mean neuroscientists at Stanford and I've spent my career exploring

1128
00:52:01,960 --> 00:52:04,080
Speaker 3: the three pound universe in our heads.

1129
00:52:04,440 --> 00:52:07,800
Speaker 2: Join me weekly to explore the relationship between your brain

1130
00:52:07,920 --> 00:52:08,640
Speaker 2: and your life.

1131
00:52:08,840 --> 00:52:11,920
Speaker 3: Because the more we know about what's running under the hood,

1132
00:52:12,200 --> 00:52:15,759
Speaker 3: better we can steer our lives. Listen to Inner Cosmos

1133
00:52:15,760 --> 00:52:19,120
Speaker 3: with David Eagleman on the iHeartRadio app, Apple Podcasts, or

1134
00:52:19,160 --> 00:52:20,799
Speaker 3: wherever you get your podcasts.

1135
00:52:21,360 --> 00:52:24,759
Speaker 7: Parents looking for a screen free, fun and engaging way

1136
00:52:24,800 --> 00:52:26,840
Speaker 7: to teach your kids the Bible as a mom. I

1137
00:52:27,040 --> 00:52:30,040
Speaker 7: was looking for the same thing, so I created Kids'

1138
00:52:30,040 --> 00:52:33,399
Speaker 7: Bible Stories podcast. Thousands of families are raving about it,

1139
00:52:33,520 --> 00:52:37,880
Speaker 7: and kids actually request to listen. With captivating sound effects, voices,

1140
00:52:37,920 --> 00:52:40,879
Speaker 7: and an apply section at the end to spark meaningful conversations,

1141
00:52:41,160 --> 00:52:44,080
Speaker 7: it's a hit with both kids and parents. Listen to

1142
00:52:44,120 --> 00:52:47,719
Speaker 7: Kids Bible Story's podcast on the iHeartRadio app, Apple Podcasts,

1143
00:52:47,800 --> 00:52:49,480
Speaker 7: or wherever you get your podcasts.