1 00:00:04,240 --> 00:00:07,240 Speaker 1: Welcome to tech Stuff, a production of I Heart Radios 2 00:00:07,320 --> 00:00:13,760 Speaker 1: How Stuff Works. Hey there, and welcome to tech Stuff. 3 00:00:13,800 --> 00:00:16,919 Speaker 1: I'm your host, Jonathan Strickland. I'm an executive producer with 4 00:00:16,960 --> 00:00:20,079 Speaker 1: iHeart Radio and a love of all things tech, and 5 00:00:20,200 --> 00:00:25,000 Speaker 1: inspired by my last episode about smoke detectors, I thought 6 00:00:25,040 --> 00:00:28,560 Speaker 1: I would do an episode about radiation and radiation detectors. 7 00:00:29,160 --> 00:00:32,479 Speaker 1: And I want to define terms like radiation and radioactivity, 8 00:00:32,520 --> 00:00:35,479 Speaker 1: to talk about the different types of radiation there are, 9 00:00:35,960 --> 00:00:40,400 Speaker 1: and to differentiate between ionizing and non ionizing radiation and 10 00:00:40,479 --> 00:00:46,680 Speaker 1: chat about the technology around it. So first, what is radiation. Well, 11 00:00:47,120 --> 00:00:50,080 Speaker 1: it's a fairly broad term with lots of different meanings 12 00:00:50,240 --> 00:00:52,960 Speaker 1: as it turns out, but I think that's part of 13 00:00:53,000 --> 00:00:55,960 Speaker 1: why there's frequently a lot of confusion around the concept 14 00:00:55,960 --> 00:00:59,040 Speaker 1: of radiation. But there are a couple of definitions that 15 00:00:59,200 --> 00:01:01,800 Speaker 1: for our purpose as we want to focus on, and 16 00:01:01,920 --> 00:01:04,880 Speaker 1: really the one that we're truly interested in is the 17 00:01:04,920 --> 00:01:09,119 Speaker 1: process of admitting radiant energy in the form of waves 18 00:01:09,240 --> 00:01:12,240 Speaker 1: or particles as a definition I took from the Miriam 19 00:01:12,360 --> 00:01:16,959 Speaker 1: Webster Dictionary. By the way, so radiation can involve electromagnetic 20 00:01:17,040 --> 00:01:20,959 Speaker 1: waves or it might involve sub atomic particles. Uh, some 21 00:01:21,160 --> 00:01:25,200 Speaker 1: radiation has the potential to be harmful, even deadly in 22 00:01:25,240 --> 00:01:30,200 Speaker 1: sufficient intensities and length of exposure. Some radiation is relatively safe, 23 00:01:30,400 --> 00:01:35,600 Speaker 1: particularly under specific controls. So let's start with some early 24 00:01:35,720 --> 00:01:40,640 Speaker 1: discoveries of electro magnetic radiation, as those predate our understanding 25 00:01:40,800 --> 00:01:46,120 Speaker 1: of particle based radiation. So our story begins in eighteen 26 00:01:46,240 --> 00:01:50,960 Speaker 1: hundred with an early scientist named William Herschel. And Willie 27 00:01:51,080 --> 00:01:53,600 Speaker 1: was interested in learning more about the spectrum of light, 28 00:01:54,200 --> 00:01:56,400 Speaker 1: and it was already understood that if you were to 29 00:01:56,400 --> 00:02:00,000 Speaker 1: pass light through a prism, you could separate light into 30 00:02:00,040 --> 00:02:03,720 Speaker 1: different colors. You know, the good old roy g BIV spectrum, 31 00:02:03,800 --> 00:02:07,920 Speaker 1: which stands for red, orange, yellow, green, blue, indigo, and violet. 32 00:02:08,480 --> 00:02:11,440 Speaker 1: The spectrum will always be in that order. Anytime you 33 00:02:11,480 --> 00:02:14,720 Speaker 1: pass light through a prism, it's going to break into 34 00:02:14,760 --> 00:02:19,480 Speaker 1: those bands in that order, and those bands actually represent 35 00:02:19,880 --> 00:02:24,760 Speaker 1: bands of frequencies of light waves. Herschel was wondering if 36 00:02:24,800 --> 00:02:28,640 Speaker 1: the different colors of light produced different amounts of heat, 37 00:02:29,160 --> 00:02:32,720 Speaker 1: So is one type of light warmer than another, So 38 00:02:32,760 --> 00:02:36,160 Speaker 1: he set up a system in which he positioned thermometers 39 00:02:36,200 --> 00:02:40,560 Speaker 1: at each color displayed from light passing through a prism. 40 00:02:40,720 --> 00:02:43,040 Speaker 1: So he sets up a prism in his window, lights 41 00:02:43,040 --> 00:02:46,800 Speaker 1: coming through it, and it's hitting a table, and it 42 00:02:46,880 --> 00:02:50,720 Speaker 1: divides up into different bands of color. He sets the 43 00:02:50,360 --> 00:02:53,720 Speaker 1: thermometers in each band of color, and he happened to 44 00:02:53,760 --> 00:02:57,000 Speaker 1: have an extra thermometer just beyond the red end of 45 00:02:57,040 --> 00:02:59,440 Speaker 1: the spectrum, so it's actually in the dark. It was 46 00:02:59,480 --> 00:03:02,560 Speaker 1: beyond the range of the visible light. He had no 47 00:03:02,600 --> 00:03:05,920 Speaker 1: way of knowing it, but he had, by happy coincidence, 48 00:03:06,280 --> 00:03:10,920 Speaker 1: placed a thermometer right where the infrared band was. And 49 00:03:10,960 --> 00:03:15,840 Speaker 1: we can't see infrared light, but that light does transmit heat. 50 00:03:16,400 --> 00:03:19,080 Speaker 1: In fact, Herschel was surprised to see that it was 51 00:03:19,200 --> 00:03:21,880 Speaker 1: that thermometer, the one that was in the darkness, just 52 00:03:22,000 --> 00:03:25,720 Speaker 1: beyond the red range, that actually registered the highest temperature 53 00:03:25,760 --> 00:03:28,600 Speaker 1: out of all the thermometers he had set out. And 54 00:03:28,639 --> 00:03:32,200 Speaker 1: we often talked about heat radiating outward from a source. 55 00:03:33,240 --> 00:03:37,480 Speaker 1: In eighteen o one, another big thinker named Johann Wilhelm 56 00:03:37,560 --> 00:03:41,760 Speaker 1: Ritter built upon Herschel's experiment. He decided to see if 57 00:03:41,760 --> 00:03:45,440 Speaker 1: perhaps there was anything beyond the other end of the spectrum, 58 00:03:45,480 --> 00:03:48,120 Speaker 1: a k a. The violet end. In fact, he really 59 00:03:48,160 --> 00:03:52,880 Speaker 1: discovered it sort of by accident. Ritter experimented by using 60 00:03:52,920 --> 00:03:56,320 Speaker 1: a substance called silver chloride, and this is a chemical 61 00:03:56,400 --> 00:04:00,800 Speaker 1: that turns black if it's exposed to sunlight. Ritter built 62 00:04:01,160 --> 00:04:05,080 Speaker 1: on the understanding that blue light would produce a greater 63 00:04:05,160 --> 00:04:09,800 Speaker 1: reaction in silver chloride than red light, so he did 64 00:04:09,800 --> 00:04:12,920 Speaker 1: a variation on Herschel's experiment. He again used a prism 65 00:04:12,960 --> 00:04:16,200 Speaker 1: to break the light into bands of color, and then 66 00:04:16,279 --> 00:04:19,480 Speaker 1: within each band of color he placed a vile a 67 00:04:19,600 --> 00:04:23,839 Speaker 1: silver chloride to see if the reactions were different across 68 00:04:23,920 --> 00:04:27,760 Speaker 1: the spectrum of light. He could see that, indeed, the 69 00:04:27,800 --> 00:04:31,360 Speaker 1: reaction did vary across the spectrum. The closer you got 70 00:04:31,400 --> 00:04:35,440 Speaker 1: to the violet side of the spectrum, the more intense 71 00:04:36,000 --> 00:04:40,600 Speaker 1: the reaction was, and it was most evident just beyond 72 00:04:41,160 --> 00:04:43,600 Speaker 1: the violet side, in an area where there was no 73 00:04:43,720 --> 00:04:47,920 Speaker 1: visible light at all. So clearly there was something going 74 00:04:47,960 --> 00:04:50,400 Speaker 1: on on that end of the spectrum. So on the 75 00:04:50,400 --> 00:04:53,599 Speaker 1: red end you were getting some sort of heat which 76 00:04:53,640 --> 00:04:56,240 Speaker 1: we now know is infrared, and on the violet end 77 00:04:56,360 --> 00:04:59,920 Speaker 1: there's something else that was really reacting to silver chloride. 78 00:05:00,400 --> 00:05:04,120 Speaker 1: So Ritter would call this chemical raise, which to this 79 00:05:04,240 --> 00:05:07,680 Speaker 1: very day we don't do anymore. Now today we call 80 00:05:07,720 --> 00:05:11,560 Speaker 1: it ultraviolet light. Herschel and Ritter had made the first 81 00:05:11,600 --> 00:05:15,599 Speaker 1: steps to increase our understanding of the electromagnetic spectrum, of 82 00:05:15,640 --> 00:05:19,680 Speaker 1: which visible light is just one tiny part, and as 83 00:05:19,680 --> 00:05:22,000 Speaker 1: we would build on that understanding, we'd also gain more 84 00:05:22,000 --> 00:05:25,480 Speaker 1: information about what effects these types of radiation can have 85 00:05:25,680 --> 00:05:28,680 Speaker 1: on us. Some of them have very little effect on us, 86 00:05:29,000 --> 00:05:32,680 Speaker 1: some of them can have a drastic effect on us. 87 00:05:33,480 --> 00:05:35,520 Speaker 1: And it would take a lot more time, but we 88 00:05:35,560 --> 00:05:38,360 Speaker 1: would gradually begin to understand that if you look at 89 00:05:38,360 --> 00:05:42,720 Speaker 1: the spectrum, it includes everything from radio waves on one 90 00:05:42,760 --> 00:05:45,880 Speaker 1: extreme end of it to gamma raise on the other 91 00:05:46,040 --> 00:05:50,720 Speaker 1: end of it, and these waves vary in wavelength, frequency, 92 00:05:50,800 --> 00:05:55,240 Speaker 1: and energy. So on one extreme end you've got those 93 00:05:55,360 --> 00:06:00,400 Speaker 1: radio waves. These can have really long wavelengths, measuring hens 94 00:06:00,400 --> 00:06:03,520 Speaker 1: of miles, like sixty two miles or a hundred kilometers 95 00:06:03,600 --> 00:06:07,840 Speaker 1: for wavelengths of certain radio frequencies. So if you had 96 00:06:07,880 --> 00:06:11,240 Speaker 1: a perfectly steady radio wave, like just imagine, it's a 97 00:06:11,240 --> 00:06:13,920 Speaker 1: perfect signal you. If you were to map it out, 98 00:06:13,920 --> 00:06:17,200 Speaker 1: it would be a beautiful sign wave. If you measured 99 00:06:17,360 --> 00:06:20,960 Speaker 1: from the peak at one point to the next peak, 100 00:06:21,600 --> 00:06:24,760 Speaker 1: that's the wavelength. That's what would have been a hundred 101 00:06:24,880 --> 00:06:30,279 Speaker 1: kilometers in distance an enormous wave. The frequency of a 102 00:06:30,360 --> 00:06:35,480 Speaker 1: wave refers to how frequently a specific point on a wavelength, 103 00:06:35,800 --> 00:06:39,239 Speaker 1: you know, like that peak, how frequently you could see 104 00:06:39,279 --> 00:06:43,159 Speaker 1: that point on each wave pass a given reference point 105 00:06:43,320 --> 00:06:47,240 Speaker 1: within a second. So with the longest radio waves at 106 00:06:47,240 --> 00:06:50,599 Speaker 1: the lowest frequencies, you're talking about a frequency of around 107 00:06:51,000 --> 00:06:55,599 Speaker 1: three thousand cycles per second, meaning that in one seconds time, 108 00:06:56,240 --> 00:07:00,440 Speaker 1: three thousand peaks past that given point of reference. Now, 109 00:07:00,440 --> 00:07:03,560 Speaker 1: one thing to keep in mind is that this is 110 00:07:03,680 --> 00:07:08,600 Speaker 1: electromagnetic radiation. An electromagnetic radiation all travels at the same speed, 111 00:07:08,839 --> 00:07:11,480 Speaker 1: that being the speed of light. Now, we do have 112 00:07:11,480 --> 00:07:15,080 Speaker 1: to remember the speed of light isn't a constant across 113 00:07:15,200 --> 00:07:20,280 Speaker 1: all media. It's a constant within each media. So we 114 00:07:20,280 --> 00:07:21,840 Speaker 1: we usually when we're talking about the speed of light, 115 00:07:21,880 --> 00:07:24,440 Speaker 1: we're talking about within the vacuum of space. But if 116 00:07:24,520 --> 00:07:28,280 Speaker 1: light is traveling through an atmosphere or through water or something, 117 00:07:28,440 --> 00:07:31,080 Speaker 1: it actually does travel at a different speed than that 118 00:07:31,680 --> 00:07:36,040 Speaker 1: because it it's all dependent upon the medium. Still, electromagnetic 119 00:07:36,320 --> 00:07:42,800 Speaker 1: radiation travels at that speed. So a wavelength of uh, 120 00:07:42,880 --> 00:07:45,600 Speaker 1: you know, one wavelength of of a radio wave is 121 00:07:45,600 --> 00:07:48,600 Speaker 1: traveling at the speed of light, as is one wavelength 122 00:07:48,640 --> 00:07:53,000 Speaker 1: of gamma radiation. However, because the radio waves are so 123 00:07:53,080 --> 00:07:57,800 Speaker 1: long and the gamma rays are so short in wavelength, 124 00:07:58,400 --> 00:08:02,160 Speaker 1: the frequency has to be different, right. The frequency of 125 00:08:02,200 --> 00:08:04,680 Speaker 1: the radio waves has to be lower than the frequency 126 00:08:04,760 --> 00:08:07,760 Speaker 1: of gamma rays because you get way more gamma rays 127 00:08:07,880 --> 00:08:11,480 Speaker 1: passing within a frame of a second, even though they're 128 00:08:11,520 --> 00:08:14,400 Speaker 1: both traveling at the same speed. All right, That gets confusing, right, 129 00:08:14,440 --> 00:08:17,280 Speaker 1: So I like to explain this with an analogy. Imagine 130 00:08:17,320 --> 00:08:22,560 Speaker 1: you've got two identical straight roads, one lane wide, and 131 00:08:22,640 --> 00:08:25,560 Speaker 1: they're right next to each other. Down one road, you 132 00:08:25,560 --> 00:08:29,480 Speaker 1: have a series of buses, and each bus super long, 133 00:08:29,800 --> 00:08:33,640 Speaker 1: measures eighteen meters in length, traveling down the road at 134 00:08:33,679 --> 00:08:37,240 Speaker 1: fifty KOs per hour, and there's one meter of space 135 00:08:37,320 --> 00:08:41,680 Speaker 1: in between each bus. So bus number one eighteen meters 136 00:08:41,760 --> 00:08:43,760 Speaker 1: long than you have a meter, and a bus number 137 00:08:43,800 --> 00:08:45,680 Speaker 1: two is eighteen meters long than you have a meter. 138 00:08:46,760 --> 00:08:49,760 Speaker 1: That's dangerous, but whatever, they're traveling down at fifty an hour, 139 00:08:49,880 --> 00:08:52,760 Speaker 1: perfectly in sync with each other. On the other road, 140 00:08:53,160 --> 00:08:55,800 Speaker 1: do you have a series of zippy little smart cars 141 00:08:55,840 --> 00:08:59,040 Speaker 1: and each smart car measures just three meters in length. 142 00:08:59,440 --> 00:09:01,720 Speaker 1: They're also going down the road at fifty kilometers per 143 00:09:01,720 --> 00:09:04,360 Speaker 1: hour with a meter of space in between each pair 144 00:09:04,400 --> 00:09:08,199 Speaker 1: of cars. Now, individual vehicles are all traveling at the 145 00:09:08,240 --> 00:09:10,920 Speaker 1: same speed, they're all traveling at fifty kilometers per hour. 146 00:09:11,040 --> 00:09:14,040 Speaker 1: But the smart cars aren't as long as the buses. 147 00:09:14,440 --> 00:09:18,760 Speaker 1: So if you were to have a accounter, there's someone 148 00:09:18,800 --> 00:09:21,360 Speaker 1: standing by the bus lane and there's someone standing by 149 00:09:21,360 --> 00:09:23,800 Speaker 1: the smart car lane, and they're holding a little counter 150 00:09:23,920 --> 00:09:27,040 Speaker 1: in their hands. The person next to the smart cars 151 00:09:27,080 --> 00:09:29,360 Speaker 1: is going to count way more smart cars in the 152 00:09:29,360 --> 00:09:32,240 Speaker 1: same amount of time as the person counting the buses. 153 00:09:32,640 --> 00:09:35,520 Speaker 1: And it's not because smart cars are traveling faster. They're not. 154 00:09:35,640 --> 00:09:38,200 Speaker 1: They're just smaller, so more of them can go by 155 00:09:38,280 --> 00:09:40,600 Speaker 1: within that given amount of time. The same thing is 156 00:09:40,640 --> 00:09:45,840 Speaker 1: true with wavelengths of the electromagnetic spectrum red light, blue light, 157 00:09:46,080 --> 00:09:48,679 Speaker 1: X rays, radio waves. They're all traveling at the same speed. 158 00:09:48,679 --> 00:09:50,920 Speaker 1: They just have different wavelengths, so they have to have 159 00:09:51,000 --> 00:09:54,280 Speaker 1: different frequencies. Now, as I said earlier, in those early 160 00:09:54,400 --> 00:09:58,360 Speaker 1: days in the nineteenth century, we didn't have this level 161 00:09:58,440 --> 00:10:02,920 Speaker 1: of understanding. We weren't aware of different wavelengths and frequencies, 162 00:10:03,200 --> 00:10:06,360 Speaker 1: and we didn't know that longer wavelengths and lower frequencies 163 00:10:06,400 --> 00:10:11,280 Speaker 1: of electromagnetic radiation carry less energy, whereas high frequencies and 164 00:10:11,480 --> 00:10:17,160 Speaker 1: very small wavelengths of electromagnetic radiation can pack way more energy. 165 00:10:17,280 --> 00:10:19,200 Speaker 1: If you were to look at the experiments of Herschel 166 00:10:19,240 --> 00:10:22,000 Speaker 1: and Ritter, you might actually think that that's not the case, 167 00:10:22,080 --> 00:10:24,960 Speaker 1: because the invisible light off the red end of the 168 00:10:25,000 --> 00:10:28,600 Speaker 1: spectrum was carrying a lot of heat. It was heating 169 00:10:28,679 --> 00:10:31,200 Speaker 1: up a thermometer more than the others, so maybe it 170 00:10:31,200 --> 00:10:34,560 Speaker 1: carries more energy. And whereas the violet side you just 171 00:10:34,600 --> 00:10:37,800 Speaker 1: saw silver chloride change color. So it would take a 172 00:10:37,840 --> 00:10:40,640 Speaker 1: lot more experimentation to get a deeper understanding of the 173 00:10:40,679 --> 00:10:44,040 Speaker 1: actual nature of electromagnetic radiation. Now to go into the 174 00:10:44,040 --> 00:10:48,480 Speaker 1: full history of how that understanding would unfold is the 175 00:10:48,520 --> 00:10:51,720 Speaker 1: stuff of college lecture series, So I'll just give very 176 00:10:51,800 --> 00:10:54,520 Speaker 1: brief summaries to get us kind of closer to our objective. 177 00:10:54,960 --> 00:10:58,920 Speaker 1: In the nineteenth century you had numerous scientists and inventors 178 00:10:58,960 --> 00:11:01,520 Speaker 1: who were observing all sorts of interesting stuff that would 179 00:11:01,600 --> 00:11:06,240 Speaker 1: later become integrated into our knowledge of electromagnetism. So Michael 180 00:11:06,240 --> 00:11:09,720 Speaker 1: Faraday did a great deal of work exploring the relationship 181 00:11:09,800 --> 00:11:14,160 Speaker 1: between electric and magnetic fields. For example, his work would 182 00:11:14,200 --> 00:11:19,120 Speaker 1: inspire a Scottish physicist named James Clerk Maxwell to look 183 00:11:19,120 --> 00:11:23,160 Speaker 1: into the matter further, and Maxwell made predictions about electromagnetic 184 00:11:23,240 --> 00:11:27,160 Speaker 1: radiation based on those early experiments and observation, saying, well, 185 00:11:27,960 --> 00:11:30,720 Speaker 1: based on what we know, I expect that will eventually 186 00:11:30,760 --> 00:11:36,200 Speaker 1: find something that fits this mathematical uh example of what 187 00:11:36,440 --> 00:11:39,280 Speaker 1: should be there, and his predictions proved to be accurate, 188 00:11:39,440 --> 00:11:41,800 Speaker 1: and they in turn would serve as an important foundation 189 00:11:41,800 --> 00:11:45,120 Speaker 1: for Albert Einstein's special theory of relativity, as the one 190 00:11:45,120 --> 00:11:48,600 Speaker 1: that gives us the famous equation equals mc squared, which 191 00:11:48,640 --> 00:11:51,520 Speaker 1: tells us that energy and mass are related at an 192 00:11:51,559 --> 00:11:56,480 Speaker 1: intrinsic level. And Maxwell's observations about electromagnetic radiation would lead 193 00:11:56,480 --> 00:12:00,240 Speaker 1: to a theory about heat radiation that in turn would 194 00:12:00,280 --> 00:12:06,240 Speaker 1: be overturned by Max Planck, whose formulation of quantum hypothesis 195 00:12:06,240 --> 00:12:09,000 Speaker 1: to describe how heat radiates would become the predominant one. 196 00:12:09,360 --> 00:12:11,560 Speaker 1: But all of that is a little outside of our scope. 197 00:12:11,640 --> 00:12:14,200 Speaker 1: So the point I wanted to make is that the 198 00:12:14,280 --> 00:12:18,840 Speaker 1: nineteenth century was a boom time for scientific observations and discoveries, 199 00:12:19,080 --> 00:12:21,040 Speaker 1: and the things we would learn would serve us well 200 00:12:21,080 --> 00:12:23,720 Speaker 1: as we moved into the next phase of understanding of radiation. 201 00:12:23,760 --> 00:12:26,760 Speaker 1: And what it's all about. So the other big discoveries 202 00:12:26,800 --> 00:12:29,800 Speaker 1: that relate to this episode came about at the end 203 00:12:30,160 --> 00:12:32,280 Speaker 1: of the nineteenth century, so we get to look at 204 00:12:32,280 --> 00:12:36,520 Speaker 1: both ends of the eighteen hundreds. In eight Vilhelm runjeon 205 00:12:36,880 --> 00:12:39,760 Speaker 1: which I mentioned him in the last episode, he was 206 00:12:39,800 --> 00:12:42,920 Speaker 1: experimenting with a cathode ray tube, and I talked about 207 00:12:43,160 --> 00:12:46,559 Speaker 1: that again in the Smoke Detective episode. Essentially, these are 208 00:12:46,640 --> 00:12:49,480 Speaker 1: devices that produce streams of electrons by heating up a 209 00:12:49,520 --> 00:12:52,080 Speaker 1: filament inside a glass vacuum tube, kind of similar to 210 00:12:52,120 --> 00:12:56,719 Speaker 1: a light bulb. Runjen found that as he applied an 211 00:12:56,720 --> 00:13:00,520 Speaker 1: electric voltage to the cathode ray tube a light detection 212 00:13:00,640 --> 00:13:04,080 Speaker 1: screen in his lab that was made out of barium 213 00:13:04,280 --> 00:13:09,600 Speaker 1: platina cyanide fluorest, it actually lit up. It detected light 214 00:13:09,640 --> 00:13:12,080 Speaker 1: even though there was no visible light there. So he 215 00:13:12,120 --> 00:13:16,400 Speaker 1: began to experiment with this phenomenon, this invisible light that 216 00:13:16,520 --> 00:13:19,880 Speaker 1: was causing this this detector to light up, and that 217 00:13:19,960 --> 00:13:25,440 Speaker 1: included putting objects between the cathode ray tube and the screen, 218 00:13:25,520 --> 00:13:27,080 Speaker 1: and he saw that whatever was coming out of the 219 00:13:27,120 --> 00:13:30,200 Speaker 1: tube seemed to be penetrating through objects and it was 220 00:13:30,240 --> 00:13:33,040 Speaker 1: still hitting the screen on the other side. He found 221 00:13:33,040 --> 00:13:38,320 Speaker 1: that if he put photographic film, the energy would interact 222 00:13:38,360 --> 00:13:40,280 Speaker 1: with the photographic film, and if you put something in 223 00:13:40,320 --> 00:13:43,760 Speaker 1: between the film and the cathode ray tube, he could 224 00:13:43,760 --> 00:13:48,160 Speaker 1: get a really interesting image of it. Uh, it's like 225 00:13:48,240 --> 00:13:52,679 Speaker 1: you could see through certain stuff pretty clearly. So, for example, 226 00:13:52,880 --> 00:13:55,480 Speaker 1: his hand, he put his hand in front of it 227 00:13:55,720 --> 00:13:58,839 Speaker 1: and he took a photo. Then the picture would show 228 00:13:59,240 --> 00:14:04,160 Speaker 1: the skeleton in hand. It would it would show through 229 00:14:04,520 --> 00:14:07,920 Speaker 1: the soft tissues of his hand, and he thought, well, 230 00:14:07,960 --> 00:14:12,080 Speaker 1: this is interesting. He discovered a new type of radiation 231 00:14:12,120 --> 00:14:14,480 Speaker 1: and he called it the X ray because what the 232 00:14:14,480 --> 00:14:17,559 Speaker 1: heck was going to call it? It was an unknown quantity, 233 00:14:17,760 --> 00:14:21,960 Speaker 1: and in mathematics we often refer to unknown quantities as X, 234 00:14:22,040 --> 00:14:24,680 Speaker 1: like solve for X. So it was meant to be 235 00:14:24,720 --> 00:14:29,640 Speaker 1: a placeholder. X rays just it turned into the permanent 236 00:14:29,720 --> 00:14:32,640 Speaker 1: name for the stuff. Now. Initially, no one was aware 237 00:14:32,880 --> 00:14:36,200 Speaker 1: that X ray radiation was potentially dangerous with its shorter 238 00:14:36,320 --> 00:14:41,360 Speaker 1: wavelength and higher frequency and energy than visible light. In fact, 239 00:14:41,400 --> 00:14:43,840 Speaker 1: no one was even sure that was another form of light. 240 00:14:44,120 --> 00:14:46,320 Speaker 1: They thought it might be, but they weren't certain, and 241 00:14:46,400 --> 00:14:50,240 Speaker 1: that wouldn't be proven until nineteen twelve. But people began 242 00:14:50,280 --> 00:14:54,560 Speaker 1: to understand that there was some potential danger the X 243 00:14:54,640 --> 00:14:59,040 Speaker 1: rays fairly early on. In eighteen nineties six, the year 244 00:14:59,160 --> 00:15:05,360 Speaker 1: after Runton's UH discovery, the journal Nature published an article 245 00:15:05,400 --> 00:15:08,560 Speaker 1: with the title The Harmful Effects of X rays. And 246 00:15:08,600 --> 00:15:11,240 Speaker 1: in that article there was a story about a guy 247 00:15:11,280 --> 00:15:14,920 Speaker 1: who had worked as an X ray demonstrator in London, 248 00:15:15,480 --> 00:15:19,960 Speaker 1: and he described the effects of X ray exposure that 249 00:15:20,400 --> 00:15:25,800 Speaker 1: he experienced, particularly on his hands, after working for a 250 00:15:25,840 --> 00:15:29,440 Speaker 1: full summer doing demonstrations with X ray machines for several 251 00:15:29,440 --> 00:15:33,320 Speaker 1: hours a day, I'm going to quote an excerpt. In 252 00:15:33,360 --> 00:15:37,240 Speaker 1: the first two or three weeks, I felt no inconvenience, 253 00:15:37,560 --> 00:15:40,000 Speaker 1: but after a while appeared on the fingers of my 254 00:15:40,160 --> 00:15:44,320 Speaker 1: right hand many dark spots which pierced under the skin, 255 00:15:44,760 --> 00:15:48,280 Speaker 1: and gradually they became very painful. The rest of the 256 00:15:48,280 --> 00:15:52,760 Speaker 1: skin was red and strongly inflamed. My hand was so 257 00:15:52,840 --> 00:15:56,160 Speaker 1: bad that I was constantly forced to bathe it in 258 00:15:56,400 --> 00:16:01,040 Speaker 1: very cold water. An ointment momentarily on the pain. But 259 00:16:01,160 --> 00:16:05,000 Speaker 1: the epidermist had dried up, had become hard and yellow 260 00:16:05,280 --> 00:16:09,600 Speaker 1: like parchment, and completely insensible, so I was not surprised 261 00:16:09,840 --> 00:16:15,320 Speaker 1: when my hand began to peel. From that point, the 262 00:16:15,360 --> 00:16:17,920 Speaker 1: guy goes on to describe how things got even worse, 263 00:16:18,320 --> 00:16:21,160 Speaker 1: like he began to lose fingernails and stuff. But I'm 264 00:16:21,160 --> 00:16:24,240 Speaker 1: gonna leave out the rest of the grizzly details. The 265 00:16:24,280 --> 00:16:26,880 Speaker 1: point is people are starting to notice that the longer 266 00:16:26,920 --> 00:16:30,680 Speaker 1: someone was exposed to X rays, the more severe the 267 00:16:30,760 --> 00:16:34,640 Speaker 1: consequences seemed to be. Short exposures did not appear to 268 00:16:34,640 --> 00:16:38,080 Speaker 1: be as serious, but this was something that people were 269 00:16:38,080 --> 00:16:41,080 Speaker 1: starting to get a little concerned about that would grow 270 00:16:41,720 --> 00:16:43,920 Speaker 1: in the years to come. But first, let's take a 271 00:16:44,000 --> 00:16:54,560 Speaker 1: quick break before we jump into that discussion. Okay, so 272 00:16:55,120 --> 00:16:57,240 Speaker 1: before we took our break, I was talking about how 273 00:16:57,280 --> 00:17:01,120 Speaker 1: people were beginning to understand that X rays could be dangerous. 274 00:17:01,880 --> 00:17:07,160 Speaker 1: That didn't stop early irresponsible implementations of X ray machines. However, 275 00:17:07,359 --> 00:17:10,399 Speaker 1: people thought of these as curiosities. They were things to 276 00:17:10,480 --> 00:17:14,919 Speaker 1: be celebrated and experienced. Thomas Edison thought everyone would have 277 00:17:15,000 --> 00:17:17,399 Speaker 1: one in their own home and thought perhaps they should 278 00:17:17,480 --> 00:17:20,280 Speaker 1: have them, because again, they didn't understand the dangers yet. 279 00:17:20,600 --> 00:17:23,880 Speaker 1: People would even have X ray parties in which guests 280 00:17:23,920 --> 00:17:27,359 Speaker 1: would take X ray photos of themselves, you know, of 281 00:17:27,440 --> 00:17:31,600 Speaker 1: their foot, or their hand, or even their face, and 282 00:17:31,760 --> 00:17:34,359 Speaker 1: they would get to keep the photographs at the end 283 00:17:34,400 --> 00:17:38,800 Speaker 1: of the party. Shoe stores installed X ray fluoroscopes to 284 00:17:38,840 --> 00:17:41,280 Speaker 1: get a look at a person's foot, And while a 285 00:17:41,320 --> 00:17:44,440 Speaker 1: person visiting the store wouldn't likely walk away with a 286 00:17:44,560 --> 00:17:47,960 Speaker 1: lethal dose of radiation, the folks who were working at 287 00:17:47,960 --> 00:17:52,080 Speaker 1: the store were exposed to X rays much more frequently 288 00:17:52,160 --> 00:17:55,919 Speaker 1: and for longer durations, and many of them would suffer 289 00:17:55,960 --> 00:17:59,360 Speaker 1: the consequences. But all of those awful discoveries would take 290 00:17:59,480 --> 00:18:04,320 Speaker 1: some times, so people didn't immediately notice the issues. Meanwhile, 291 00:18:04,680 --> 00:18:07,720 Speaker 1: let's get back to the discovery of radioactivity by talking 292 00:18:07,760 --> 00:18:12,600 Speaker 1: about the other kind of radiation, not the electro magnetic type. 293 00:18:12,960 --> 00:18:15,560 Speaker 1: So in eighteen ninety six, which was that same year 294 00:18:15,720 --> 00:18:18,600 Speaker 1: that the Nature article about the dangers of X rays 295 00:18:18,680 --> 00:18:22,240 Speaker 1: came out, there was a physicist named al Marie Beccarel 296 00:18:22,640 --> 00:18:25,840 Speaker 1: who was wondering if some materials he was working with 297 00:18:25,960 --> 00:18:30,040 Speaker 1: might produce the same sort of energy that Rundgen's X 298 00:18:30,160 --> 00:18:33,920 Speaker 1: rays seemed to create. One of those materials that Beckerel 299 00:18:34,040 --> 00:18:37,800 Speaker 1: was working with was a crystal made up of uranium salts. Now, 300 00:18:37,840 --> 00:18:41,959 Speaker 1: the various materials Beccarel had interest in all shared a 301 00:18:42,000 --> 00:18:45,959 Speaker 1: common trait. They were all phosphorescent, so they could all glow, 302 00:18:46,840 --> 00:18:49,560 Speaker 1: and he wondered if they were giving off the same 303 00:18:49,600 --> 00:18:52,920 Speaker 1: sort of invisible light stuff that run Gen was observing 304 00:18:52,920 --> 00:18:56,119 Speaker 1: with X rays. So Beckarel set up an experiment. He 305 00:18:56,200 --> 00:18:59,679 Speaker 1: put down a photographic plate. He totally covered it so 306 00:18:59,720 --> 00:19:01,720 Speaker 1: that one of it would be exposed to light because 307 00:19:01,720 --> 00:19:05,639 Speaker 1: that would activate the photoreactive chemicals on the plate. And 308 00:19:05,720 --> 00:19:08,760 Speaker 1: on top of the covering he put a selection of 309 00:19:08,840 --> 00:19:13,720 Speaker 1: his phosphorescent crystals to see if any of them would 310 00:19:13,720 --> 00:19:17,159 Speaker 1: interact with the photo reactive chemicals. And he exposed the 311 00:19:17,160 --> 00:19:19,399 Speaker 1: whole thing to the sun, you know, thinking that the 312 00:19:19,440 --> 00:19:23,800 Speaker 1: sun would charge these various crystals. And at the end 313 00:19:23,840 --> 00:19:26,000 Speaker 1: of the experiment he discovered that out of all the 314 00:19:26,000 --> 00:19:28,280 Speaker 1: different things he was testing, only one seemed to have 315 00:19:28,320 --> 00:19:31,040 Speaker 1: any effect at all, and that was the rock crystal 316 00:19:31,080 --> 00:19:34,199 Speaker 1: that was actually made up of uranium salt, and that 317 00:19:34,280 --> 00:19:36,200 Speaker 1: was the only one that seemed to have fogged up 318 00:19:36,280 --> 00:19:40,199 Speaker 1: the the photoplate. So he thought, well, I'll do a 319 00:19:40,240 --> 00:19:43,240 Speaker 1: longer test. I'll leave it out in the sun longer, 320 00:19:43,320 --> 00:19:45,960 Speaker 1: see if I get a bigger, more clear result. But 321 00:19:46,040 --> 00:19:49,040 Speaker 1: the weather at that point wasn't cooperating. It had gotten cloudy, 322 00:19:49,119 --> 00:19:50,760 Speaker 1: so he couldn't put it out in the sun. So 323 00:19:51,119 --> 00:19:55,200 Speaker 1: he takes his photographic plates and his uranium salts and 324 00:19:55,400 --> 00:19:58,119 Speaker 1: he stores them away and waits for the weather to 325 00:19:58,160 --> 00:20:00,560 Speaker 1: get better. So they were actually stored next to each 326 00:20:00,600 --> 00:20:03,960 Speaker 1: other in a dark cabinet. Several days later, as the 327 00:20:03,960 --> 00:20:06,879 Speaker 1: weather was starting to finally clear out, he was getting 328 00:20:06,880 --> 00:20:10,040 Speaker 1: ready to conduct his experiment, but he decided, you know what, 329 00:20:10,240 --> 00:20:12,840 Speaker 1: before I do this, I better make sure these photographic 330 00:20:12,880 --> 00:20:16,720 Speaker 1: plates are still good, because the chemicals can actually expire, 331 00:20:17,040 --> 00:20:20,800 Speaker 1: and I'd be wasting my time if they aren't working anymore. 332 00:20:21,119 --> 00:20:24,160 Speaker 1: So he picks one and develops it, and it happened 333 00:20:24,200 --> 00:20:27,040 Speaker 1: to be one that was close to the iranium salts. 334 00:20:27,320 --> 00:20:30,439 Speaker 1: Rock He was surprised to discover that the bits of 335 00:20:30,440 --> 00:20:33,080 Speaker 1: the photographic plate that had been close to those uranium 336 00:20:33,080 --> 00:20:36,119 Speaker 1: salts had images on them, even though the salts had 337 00:20:36,160 --> 00:20:38,320 Speaker 1: not been exposed to sunlight. They've been stored in a 338 00:20:38,440 --> 00:20:42,400 Speaker 1: dark cupboard, and he concluded that the uranium salts themselves 339 00:20:42,560 --> 00:20:45,000 Speaker 1: were giving off some sort of emission that was being 340 00:20:45,080 --> 00:20:48,920 Speaker 1: captured on this photographic plate. Henri Becarel had a couple 341 00:20:48,920 --> 00:20:54,280 Speaker 1: of enterprising and brilliant assistants. One was Pierre Curie and 342 00:20:54,359 --> 00:20:58,560 Speaker 1: the other was Marie Sklodowska, who would marry Pierre and 343 00:20:58,600 --> 00:21:04,840 Speaker 1: become Marie Curie. She uh really was fascinated by radioactivity, 344 00:21:05,000 --> 00:21:07,119 Speaker 1: and together with her husband, they began to study the 345 00:21:07,240 --> 00:21:11,000 Speaker 1: ranium salts as well as looking for other similar materials 346 00:21:11,040 --> 00:21:15,760 Speaker 1: that seemed to display this radioactive phenomena. They tested some 347 00:21:15,840 --> 00:21:19,439 Speaker 1: mining operation waste. It's called a pitch blend. The mining 348 00:21:19,680 --> 00:21:21,600 Speaker 1: operations were happy to get rid of it because it 349 00:21:21,680 --> 00:21:25,480 Speaker 1: was just run off from their operations, and they found 350 00:21:25,520 --> 00:21:28,720 Speaker 1: that it could contained traces of radioactive material, and eventually 351 00:21:28,720 --> 00:21:31,080 Speaker 1: they were able to separate a small amount of it 352 00:21:31,200 --> 00:21:33,600 Speaker 1: from the rest of the pitch blend, and it would 353 00:21:33,680 --> 00:21:38,200 Speaker 1: later be called radium. It was far more radioactive than 354 00:21:38,280 --> 00:21:42,320 Speaker 1: the uranium salts they had already worked with. The Curies 355 00:21:42,400 --> 00:21:44,960 Speaker 1: and Beckrel would receive the Nobel Prize in Physics for 356 00:21:45,000 --> 00:21:49,160 Speaker 1: their discoveries. Runen also received one earlier for his discovery 357 00:21:49,160 --> 00:21:52,800 Speaker 1: of X rays, and then Pierre Curie would later tragically 358 00:21:52,920 --> 00:21:55,919 Speaker 1: die in a traffic accident. Marie would go on to 359 00:21:56,000 --> 00:22:00,159 Speaker 1: discover another radioact development, this one called polonium, and she 360 00:22:00,200 --> 00:22:03,360 Speaker 1: would receive a second Nobel Prize, though that second one 361 00:22:03,440 --> 00:22:06,240 Speaker 1: was in chemistry. She's one of only a few people 362 00:22:06,240 --> 00:22:09,760 Speaker 1: who have ever received more than one Nobel Prize. Now, 363 00:22:09,760 --> 00:22:13,240 Speaker 1: one thing Beckerel did with his own research was proved 364 00:22:13,640 --> 00:22:16,639 Speaker 1: that the energy coming out of this uranium salt was 365 00:22:16,720 --> 00:22:19,600 Speaker 1: not the same thing as X rays, and he did 366 00:22:19,640 --> 00:22:23,040 Speaker 1: this by testing the uranium salts against X rays with 367 00:22:23,080 --> 00:22:26,480 Speaker 1: a device that could generate a magnetic field. So X 368 00:22:26,560 --> 00:22:30,440 Speaker 1: rays would pass through the magnetic field unimpeded. And that's 369 00:22:30,440 --> 00:22:33,920 Speaker 1: because X ray radiation has no electric charge, and thus 370 00:22:33,920 --> 00:22:36,320 Speaker 1: it has no magnetic field of its own, so it's 371 00:22:36,320 --> 00:22:38,800 Speaker 1: not affected by magnetic field. It just passes through. Is 372 00:22:38,840 --> 00:22:41,959 Speaker 1: that there's nothing else there but the radiation coming from 373 00:22:42,000 --> 00:22:46,679 Speaker 1: the uranium salts bent upon encountering the magnetic field, and 374 00:22:46,720 --> 00:22:48,800 Speaker 1: that told Beckarel that whatever was coming out of the 375 00:22:48,880 --> 00:22:52,280 Speaker 1: uranium salts had an electric charge to it, because it 376 00:22:52,359 --> 00:22:53,879 Speaker 1: had to have an electric charge in or to have 377 00:22:53,920 --> 00:22:57,240 Speaker 1: its own magnetic field and thus be either attracted or 378 00:22:57,280 --> 00:23:00,840 Speaker 1: repelled by the magnetic field and his testing vice. So 379 00:23:00,920 --> 00:23:05,359 Speaker 1: Beckerel tested numerous types of radioactive substances using this approach 380 00:23:05,720 --> 00:23:10,160 Speaker 1: and observed three basic results. Either radiation would bend one 381 00:23:10,200 --> 00:23:15,399 Speaker 1: way using certain radioactive materials, and he would conclude, this 382 00:23:15,520 --> 00:23:19,919 Speaker 1: is a positive radiation material because it is being attracted 383 00:23:19,960 --> 00:23:22,240 Speaker 1: to the negative side of the magnetic field and repelled 384 00:23:22,240 --> 00:23:25,200 Speaker 1: by the positive side, or it would bend the other way, 385 00:23:25,359 --> 00:23:27,639 Speaker 1: so he would have the opposite conclusion. Okay, this is 386 00:23:27,760 --> 00:23:31,159 Speaker 1: negative radiation because it's being attracted to the positive side 387 00:23:31,200 --> 00:23:34,480 Speaker 1: and repelled by the negative side, or it passed straight 388 00:23:34,520 --> 00:23:37,200 Speaker 1: through like X rays, and it would have no electrical 389 00:23:37,240 --> 00:23:39,280 Speaker 1: charge at all, so it would be neutral. So you 390 00:23:39,320 --> 00:23:44,040 Speaker 1: had positive, negative, and electrically neutral radiation. In their work, 391 00:23:44,240 --> 00:23:48,199 Speaker 1: the Curies and Beckarel noted that prolonged exposure to some 392 00:23:48,240 --> 00:23:51,880 Speaker 1: of these radioactive materials would result in injuries and ailments, 393 00:23:53,080 --> 00:23:55,480 Speaker 1: like if you handled some of the more radioactive stuff 394 00:23:55,480 --> 00:23:57,840 Speaker 1: like radium for any length of time, you could actually 395 00:23:57,880 --> 00:24:02,280 Speaker 1: get burns on your skin, and you could suffer radiation sickness, 396 00:24:02,320 --> 00:24:06,919 Speaker 1: which includes symptoms like nausea, but the extent of the 397 00:24:07,040 --> 00:24:12,200 Speaker 1: damage was unknown for years. Marie cry died in nineteen 398 00:24:12,320 --> 00:24:16,680 Speaker 1: thirty four of a plastic anemia, which was probably a 399 00:24:16,720 --> 00:24:20,639 Speaker 1: consequence of her exposure to radioactive material over the years. 400 00:24:21,200 --> 00:24:24,720 Speaker 1: It certainly would have increased the odds of her developing that, 401 00:24:25,280 --> 00:24:28,000 Speaker 1: and that's something that is is good to just mention 402 00:24:28,200 --> 00:24:31,159 Speaker 1: in general is that when we think of radiation, we 403 00:24:31,200 --> 00:24:34,760 Speaker 1: often think of the radiation sickness, the sort of acute 404 00:24:34,840 --> 00:24:38,080 Speaker 1: symptoms you can have if you have a sudden exposure 405 00:24:38,119 --> 00:24:42,159 Speaker 1: to an intense amount of radiation. But in many ways, 406 00:24:42,560 --> 00:24:47,159 Speaker 1: the consequences of exposure to radiation are really more about 407 00:24:47,240 --> 00:24:53,240 Speaker 1: the increased risk of developing UH conditions like cancer. UH. 408 00:24:53,280 --> 00:24:56,159 Speaker 1: And it doesn't necessarily mean that if you do develop cancer, 409 00:24:56,240 --> 00:24:58,960 Speaker 1: that it was a direct result of that exposure to radiation, 410 00:24:59,560 --> 00:25:02,520 Speaker 1: but rather or that the exposure to radiation increased the 411 00:25:02,560 --> 00:25:06,359 Speaker 1: odds that you would develop cancer. It's a complicated thing 412 00:25:06,440 --> 00:25:09,239 Speaker 1: to look at because without knowing all the variables, you 413 00:25:09,280 --> 00:25:14,880 Speaker 1: cannot say conclusively that X caused why, but you can't 414 00:25:14,880 --> 00:25:18,920 Speaker 1: say that X made Y way more likely. That's what 415 00:25:19,000 --> 00:25:23,159 Speaker 1: we think with Currie, that she probably developed a plastic 416 00:25:23,160 --> 00:25:26,159 Speaker 1: anemia as a consequence of this exposure to stuff like 417 00:25:26,280 --> 00:25:29,359 Speaker 1: radium over the years. Many of her belongings and even 418 00:25:29,640 --> 00:25:34,280 Speaker 1: a cookbook she used, are actually stored in shielded containers 419 00:25:34,320 --> 00:25:38,800 Speaker 1: to this day because they're still radioactive dangerously. So the 420 00:25:38,880 --> 00:25:44,200 Speaker 1: lack of understanding about the consequences of radiation exposure would 421 00:25:44,240 --> 00:25:49,080 Speaker 1: have many more nasty consequences, just as it had with 422 00:25:49,280 --> 00:25:54,280 Speaker 1: the X ray fad. For example, because radium is phosphorescent, 423 00:25:54,760 --> 00:25:57,760 Speaker 1: it was seen as a useful material for stuff like 424 00:25:58,200 --> 00:26:02,159 Speaker 1: the hands of watches, like analog watches. He would paint 425 00:26:02,200 --> 00:26:06,119 Speaker 1: an analog watches minute and our hands with radium, and 426 00:26:06,160 --> 00:26:08,040 Speaker 1: that would make it glow in the dark and made 427 00:26:08,080 --> 00:26:10,399 Speaker 1: it really easy to read the time, even if you 428 00:26:10,440 --> 00:26:13,520 Speaker 1: were in low lighting. While the amount of radium on 429 00:26:13,600 --> 00:26:17,080 Speaker 1: these watches was very very small and not likely to 430 00:26:17,160 --> 00:26:21,240 Speaker 1: harm somebody who was wearing the watch, the employees responsible 431 00:26:21,280 --> 00:26:27,160 Speaker 1: for painting the watch hands received way more radiation exposure. Colloquially, 432 00:26:27,400 --> 00:26:32,679 Speaker 1: they were called radium girls, and the management positions at 433 00:26:32,680 --> 00:26:37,919 Speaker 1: these facilities frequently had significant protection from radiation, but the 434 00:26:38,000 --> 00:26:40,880 Speaker 1: same could not be said for the women on the 435 00:26:40,920 --> 00:26:44,359 Speaker 1: front lines, the women actually doing the work painting the 436 00:26:44,480 --> 00:26:49,000 Speaker 1: radium onto these watch hands. It also wasn't uncommon for 437 00:26:49,080 --> 00:26:52,439 Speaker 1: a worker to lick the end of her brush to 438 00:26:52,640 --> 00:26:55,199 Speaker 1: shape it so that she could more easily paint the 439 00:26:55,240 --> 00:26:59,320 Speaker 1: watch hand. So that meant these workers were occasionally depositing 440 00:26:59,480 --> 00:27:02,440 Speaker 1: little amounts of radium directly on their tongues. They were 441 00:27:02,640 --> 00:27:08,600 Speaker 1: ingesting radium. Radium when ingested, will deposit itself in bone, 442 00:27:09,119 --> 00:27:12,000 Speaker 1: much like calcium would, so several of the workers would 443 00:27:12,080 --> 00:27:16,120 Speaker 1: ultimately grow ill with radiation sickness. A group of five 444 00:27:16,200 --> 00:27:19,760 Speaker 1: of them later brought a lawsuit against their company. That 445 00:27:19,800 --> 00:27:24,680 Speaker 1: company was the United States Radium Company. They charged them 446 00:27:24,680 --> 00:27:28,560 Speaker 1: with being irresponsible in areas of health and safety, and 447 00:27:28,600 --> 00:27:32,639 Speaker 1: in turn that prompted a detailed study into what the 448 00:27:32,720 --> 00:27:36,560 Speaker 1: long term effects of radium exposure are and it's awful 449 00:27:36,680 --> 00:27:39,880 Speaker 1: that our knowledge came at such a steep price. At 450 00:27:39,880 --> 00:27:42,960 Speaker 1: the same time, the results of that study would lead 451 00:27:43,000 --> 00:27:46,439 Speaker 1: to massive changes in health and safety regulations for the 452 00:27:46,480 --> 00:27:50,280 Speaker 1: benefit of workers in the United States. From these discoveries, 453 00:27:50,520 --> 00:27:54,480 Speaker 1: physicists began to learn more about the nature of radioactive 454 00:27:54,520 --> 00:27:58,880 Speaker 1: material in general. They observed that there were different kinds 455 00:27:59,000 --> 00:28:04,560 Speaker 1: of radiation beyond just calling it positive, negative, or electrically neutral. 456 00:28:05,200 --> 00:28:08,640 Speaker 1: Some radiation seem to have more penetrative abilities. They could 457 00:28:08,680 --> 00:28:13,000 Speaker 1: penetrate further into solid matter than other types of radiation. 458 00:28:13,320 --> 00:28:16,000 Speaker 1: So you might have one type of radiation that isn't 459 00:28:16,040 --> 00:28:19,359 Speaker 1: able to penetrate solid matter effectively, and another one seems 460 00:28:19,359 --> 00:28:22,320 Speaker 1: to go right through stuff as if there's no problem. 461 00:28:22,400 --> 00:28:26,800 Speaker 1: A physicist named Ernest Rutherford conducted numerous experiments with radioactive 462 00:28:26,840 --> 00:28:29,600 Speaker 1: material and at this point we were beginning to understand 463 00:28:29,600 --> 00:28:33,600 Speaker 1: that radioactivity was a process in which certain materials undergo 464 00:28:34,520 --> 00:28:38,280 Speaker 1: a process called decay, and that is the form that 465 00:28:38,320 --> 00:28:43,320 Speaker 1: they are in. The radioactive form is inherently unstable. You 466 00:28:43,360 --> 00:28:44,800 Speaker 1: can if you want to think of it in terms 467 00:28:44,840 --> 00:28:48,320 Speaker 1: of want, I mean putting motivation is ridiculous because we're 468 00:28:48,320 --> 00:28:52,000 Speaker 1: talking about atomic particles here. But it's a form of 469 00:28:52,040 --> 00:28:55,200 Speaker 1: an atom that does not want to be that form. 470 00:28:55,320 --> 00:29:00,280 Speaker 1: It's unstable. So these materials will spontaneously but not necessary early, 471 00:29:00,440 --> 00:29:04,880 Speaker 1: quickly break apart and give off energy and subatomic particles 472 00:29:04,920 --> 00:29:09,240 Speaker 1: as they decay to a more stable form. Rutherford classified 473 00:29:09,280 --> 00:29:13,360 Speaker 1: three types of radiation. He said this was all based 474 00:29:13,360 --> 00:29:16,120 Speaker 1: off the penetrative properties of radiation, how far they could 475 00:29:16,120 --> 00:29:21,640 Speaker 1: penetrate into matter. The three types he classified were alpha radiation, 476 00:29:21,880 --> 00:29:26,560 Speaker 1: beta radiation, and gamma radiation. Alpha particles had the least 477 00:29:26,560 --> 00:29:30,000 Speaker 1: amount of ability to penetrate matter, and gamma rays were 478 00:29:30,040 --> 00:29:34,880 Speaker 1: the opposite. They could very easily penetrate matter. Upon further study, 479 00:29:35,200 --> 00:29:40,760 Speaker 1: scientists discovered that an alpha particle is relatively massive on 480 00:29:40,800 --> 00:29:43,640 Speaker 1: the atomic scale of things. It actually consists of an 481 00:29:43,640 --> 00:29:47,960 Speaker 1: ejected helium nucleus. A helium nucleus is two protons and 482 00:29:48,040 --> 00:29:51,240 Speaker 1: two neutrons. This is the type of radiation given off 483 00:29:51,280 --> 00:29:53,880 Speaker 1: by a mera sirium to forty one. That's the radioactive 484 00:29:53,880 --> 00:29:56,680 Speaker 1: material that's inside smoke detectors that I talked about in 485 00:29:56,680 --> 00:30:00,440 Speaker 1: the last episode. The ionization chambers have this type of 486 00:30:00,480 --> 00:30:03,720 Speaker 1: radioactive material in them, so you probably have some of 487 00:30:03,720 --> 00:30:07,080 Speaker 1: the stuff in your house right now. Alpha particles are 488 00:30:07,120 --> 00:30:11,440 Speaker 1: not able to penetrate matter very well, and they're big 489 00:30:11,560 --> 00:30:14,800 Speaker 1: enough and slow enough that they can't really get through skin, 490 00:30:15,200 --> 00:30:17,719 Speaker 1: at least not most of the time, so they're not 491 00:30:17,840 --> 00:30:21,840 Speaker 1: likely to have it affects you. Uh. They can't even 492 00:30:21,880 --> 00:30:24,280 Speaker 1: go through very much air. After a couple of inches, 493 00:30:24,280 --> 00:30:27,840 Speaker 1: they've lost the energy to move forward. Breathing in alpha 494 00:30:27,920 --> 00:30:30,440 Speaker 1: particles would be a real risk, and you wouldn't want 495 00:30:30,440 --> 00:30:32,920 Speaker 1: to swallow any of it either, so you don't want 496 00:30:32,960 --> 00:30:35,840 Speaker 1: to come into contact with the stuff, But having it 497 00:30:36,120 --> 00:30:38,840 Speaker 1: enclosed in a smoke detector in its own little chamber 498 00:30:38,880 --> 00:30:43,080 Speaker 1: in the smoke detector is more than enough protection that 499 00:30:43,200 --> 00:30:47,920 Speaker 1: you wouldn't receive any sort of significant radiation exposure from 500 00:30:48,080 --> 00:30:51,240 Speaker 1: the ameer sirium inside a smoke detector. You would receive 501 00:30:51,600 --> 00:30:54,440 Speaker 1: way more if you just went outside for a few hours. 502 00:30:54,840 --> 00:30:58,600 Speaker 1: So it's not that big. It's it's it's like background 503 00:30:58,680 --> 00:31:04,160 Speaker 1: levels of radiation UM. Beta particles are lighter than alpha particles, 504 00:31:04,200 --> 00:31:08,800 Speaker 1: and they move fast. They're actually ejected electrons. They can 505 00:31:08,840 --> 00:31:12,320 Speaker 1: travel further than alpha particles through the air. An alpha particle, 506 00:31:12,480 --> 00:31:14,120 Speaker 1: like I said, I can only move a couple of inches, 507 00:31:14,360 --> 00:31:19,200 Speaker 1: but beta particles can move several feet. They're also moderately penetrating. 508 00:31:19,560 --> 00:31:22,080 Speaker 1: They can pass through human skin, at least under the 509 00:31:22,160 --> 00:31:24,960 Speaker 1: surface level of human skin, So if you're in contact 510 00:31:24,960 --> 00:31:28,000 Speaker 1: with beta emitting material for a prolonged amount of time, 511 00:31:28,560 --> 00:31:31,640 Speaker 1: you could suffer a skin injury like a skin burn. UH. 512 00:31:31,760 --> 00:31:37,480 Speaker 1: Stuff that emits beta radiation includes carbon fourteen, sulfur thirty five, 513 00:31:37,560 --> 00:31:41,200 Speaker 1: and strontium ninety UH. Those numbers at the ends of 514 00:31:41,240 --> 00:31:45,160 Speaker 1: those names are important that designates isotopes. Isotopes are forms 515 00:31:45,240 --> 00:31:47,600 Speaker 1: of an atom that have a different number of neutrons, 516 00:31:47,680 --> 00:31:49,400 Speaker 1: but of course they have the same number of protons 517 00:31:49,400 --> 00:31:52,240 Speaker 1: and electrons. If you start having different number of protons, 518 00:31:52,240 --> 00:31:54,960 Speaker 1: then you end up with a different element. So the 519 00:31:55,000 --> 00:31:59,160 Speaker 1: most common form of carbon is carbon twelve. Carbon twelve 520 00:31:59,160 --> 00:32:02,520 Speaker 1: has six proto ons and six neutrons, but you can 521 00:32:02,560 --> 00:32:07,560 Speaker 1: also find carbon fourteen that has six protons and eight neutrons, 522 00:32:07,600 --> 00:32:12,280 Speaker 1: but it's unstable. It will undergo radioactive decay over time, 523 00:32:12,360 --> 00:32:15,520 Speaker 1: so it will spontaneously decay and give off beta emissions. 524 00:32:16,360 --> 00:32:19,840 Speaker 1: Gamma radiation, like X ray radiation, is a form of 525 00:32:19,920 --> 00:32:23,160 Speaker 1: electromagnetic radiation. If you were to look at the full 526 00:32:23,200 --> 00:32:26,960 Speaker 1: spectrum of electromagnetic radiation, radio waves are on one end 527 00:32:27,280 --> 00:32:30,680 Speaker 1: with a very long, low frequency low energy waves. Gamma 528 00:32:30,760 --> 00:32:33,440 Speaker 1: rays are on the opposite, so this is the very 529 00:32:33,560 --> 00:32:39,200 Speaker 1: very very short wavelengths incredibly high frequencies. They pack a 530 00:32:39,240 --> 00:32:43,200 Speaker 1: ton of energy in them. X rays are slightly less energetic, 531 00:32:43,240 --> 00:32:45,680 Speaker 1: but there are still far more powerful than visible light, 532 00:32:46,040 --> 00:32:48,720 Speaker 1: which is why they can penetrate through solid objects better 533 00:32:48,760 --> 00:32:51,920 Speaker 1: than visible light could, and gamma rays are even better 534 00:32:51,960 --> 00:32:55,520 Speaker 1: at it than X rays are. These rays are electrically neutral, 535 00:32:55,680 --> 00:32:58,320 Speaker 1: so magnetic fields won't cause them to change their paths. 536 00:32:58,360 --> 00:33:01,800 Speaker 1: They'll just keep going straight. They can travel many feet 537 00:33:01,960 --> 00:33:05,200 Speaker 1: through the air. They can penetrate several inches into human tissue. 538 00:33:05,240 --> 00:33:10,840 Speaker 1: In fact, it requires significant shielding to protect against gamma radiation. 539 00:33:11,680 --> 00:33:15,560 Speaker 1: Radium two twenty six amidst gamma radiation, as do several 540 00:33:15,600 --> 00:33:19,640 Speaker 1: other radioactive materials, And this is really dangerous stuff. It 541 00:33:19,680 --> 00:33:22,320 Speaker 1: will not turn you into the Incredible Hulk, but it 542 00:33:22,440 --> 00:33:27,800 Speaker 1: might cause nasty, nasty problems for you. Now, in addition 543 00:33:27,840 --> 00:33:30,840 Speaker 1: to all these observations and the growing realization that some 544 00:33:30,920 --> 00:33:34,400 Speaker 1: forms of radioactivity posed a serious health hazard to humans, 545 00:33:34,760 --> 00:33:38,120 Speaker 1: scientists discovered that these forms of radiation would interact with 546 00:33:38,160 --> 00:33:42,920 Speaker 1: other particles and ionize them. That is, when the interaction 547 00:33:42,960 --> 00:33:47,080 Speaker 1: would happen, the particles would have electrons split off of them, 548 00:33:47,200 --> 00:33:49,880 Speaker 1: and by particles, I'm really talking about atoms and molecules, 549 00:33:49,880 --> 00:33:52,080 Speaker 1: I shouldn't use the word particle. I should say these 550 00:33:52,080 --> 00:33:54,920 Speaker 1: atoms are molecules. When they would encounter this kind of radiation, 551 00:33:55,240 --> 00:33:59,400 Speaker 1: they would have electrons stripped away, and the remaining molecule 552 00:33:59,560 --> 00:34:03,160 Speaker 1: or atom would end up having a net positive charge 553 00:34:03,640 --> 00:34:06,920 Speaker 1: because it just lost electrons. Electrons have a negative charge. 554 00:34:07,320 --> 00:34:12,319 Speaker 1: Were referred to this general type of radiation as ionizing radiation. 555 00:34:12,760 --> 00:34:18,680 Speaker 1: It has created ions. Not all radiation is ionizing. Radio 556 00:34:18,680 --> 00:34:23,360 Speaker 1: waves for example, are not ionizing radiation, nor are microwaves 557 00:34:23,560 --> 00:34:27,120 Speaker 1: or visible light. These types of radiation don't have enough 558 00:34:27,320 --> 00:34:31,920 Speaker 1: energy to ionize other particles, and it's why it's safe 559 00:34:31,920 --> 00:34:35,240 Speaker 1: for us to broadcast radio waves and to walk around 560 00:34:35,640 --> 00:34:37,719 Speaker 1: with radio waves going all over the place. They don't 561 00:34:37,760 --> 00:34:40,200 Speaker 1: affect us, we don't interact with them. Makes sense that 562 00:34:40,239 --> 00:34:43,280 Speaker 1: we would evolve in such a way where the radio 563 00:34:43,320 --> 00:34:46,040 Speaker 1: waves wouldn't affect us. This is why if you were 564 00:34:46,040 --> 00:34:48,400 Speaker 1: to live next to a cell phone tower, you would 565 00:34:48,400 --> 00:34:52,600 Speaker 1: not receive harmful radiation in the form of ionizing radiation, 566 00:34:53,120 --> 00:34:56,759 Speaker 1: because that's not the type that cell phone towers can emit. Uh, 567 00:34:57,480 --> 00:35:01,960 Speaker 1: they just don't pack the punch at ionizing radiation like alpha, 568 00:35:02,160 --> 00:35:05,400 Speaker 1: beta and gamma radiation as a different story, That stuff 569 00:35:05,440 --> 00:35:09,000 Speaker 1: really can mess us up, and for that reason, it's 570 00:35:09,000 --> 00:35:11,200 Speaker 1: a good thing to be able to detect it so 571 00:35:11,239 --> 00:35:15,280 Speaker 1: that we can remove ourselves or the radioactive material from 572 00:35:15,320 --> 00:35:18,719 Speaker 1: the environment that otherwise would pose a real threat to 573 00:35:18,760 --> 00:35:21,239 Speaker 1: our long term health. So when we come back, I'll 574 00:35:21,280 --> 00:35:24,600 Speaker 1: talk more about what is actually going on with the 575 00:35:24,680 --> 00:35:28,480 Speaker 1: radioactive interactions in our bodies, as well as the device 576 00:35:28,640 --> 00:35:31,840 Speaker 1: used to detect it, and it's typically called a Geiger counter. 577 00:35:32,120 --> 00:35:42,440 Speaker 1: But we'll be right back and I'll talk about then. Okay, 578 00:35:42,800 --> 00:35:47,320 Speaker 1: So radiation interacting with the human body that ionizing radiation 579 00:35:48,880 --> 00:35:52,319 Speaker 1: can damage the cells in our body. Now, we have 580 00:35:52,480 --> 00:35:56,400 Speaker 1: systems in our body that are really good at repairing damage, 581 00:35:56,800 --> 00:36:01,760 Speaker 1: So it's entirely possible to encounter radiation suffer some damage 582 00:36:01,800 --> 00:36:03,640 Speaker 1: as long as the damage. As long as the radiation 583 00:36:03,680 --> 00:36:07,759 Speaker 1: wasn't so intense and the exposure so extreme that you 584 00:36:07,800 --> 00:36:14,080 Speaker 1: didn't have uh, mortal wounds from acute exposure, you might 585 00:36:14,239 --> 00:36:18,840 Speaker 1: very well recover without any issue. But radiation can damage 586 00:36:18,960 --> 00:36:24,040 Speaker 1: the d n A inside ourselves, and occasionally that can 587 00:36:24,120 --> 00:36:27,840 Speaker 1: lead to other big problems, such as the development of cancer, 588 00:36:28,120 --> 00:36:31,839 Speaker 1: which is why we say exposure to radiation increases your 589 00:36:31,960 --> 00:36:36,080 Speaker 1: risk of developing cancer. It doesn't necessarily mean that we 590 00:36:36,120 --> 00:36:40,799 Speaker 1: can easily draw a line from exposure to development, but 591 00:36:40,960 --> 00:36:45,000 Speaker 1: we certainly know that it increases your risk of developing it. 592 00:36:45,000 --> 00:36:48,640 Speaker 1: It could be the reason that someone develops cancer. But 593 00:36:49,680 --> 00:36:53,719 Speaker 1: there's so many variables it's impossible to say in any 594 00:36:54,000 --> 00:36:57,000 Speaker 1: you know, given case, uh, specific cases, you might be 595 00:36:57,040 --> 00:36:59,719 Speaker 1: able to trace it down, but now in general, you 596 00:36:59,760 --> 00:37:02,960 Speaker 1: can't just easily make that that conclusion. It is clear 597 00:37:03,480 --> 00:37:07,840 Speaker 1: that acute exposure to high levels of of ionizing radiation 598 00:37:08,560 --> 00:37:13,120 Speaker 1: will cause injury and sickness and increase risk of more 599 00:37:13,239 --> 00:37:17,920 Speaker 1: serious health problems further down the line. So we want 600 00:37:17,960 --> 00:37:21,200 Speaker 1: to be able to detect that stuff early before we 601 00:37:21,480 --> 00:37:26,480 Speaker 1: risk having a longer exposure to it. Radiations invisible frequently 602 00:37:27,000 --> 00:37:31,080 Speaker 1: exposure to lower levels of it could be very harmful, 603 00:37:31,080 --> 00:37:34,560 Speaker 1: but they might not be noticeable. We might not register 604 00:37:34,680 --> 00:37:39,319 Speaker 1: it just from our own personal experience. So how do 605 00:37:39,400 --> 00:37:41,040 Speaker 1: we detect it? And that's where we get to the 606 00:37:41,040 --> 00:37:44,600 Speaker 1: Geiger Counter. It's named after a guy named Hans Geiger Counter. 607 00:37:45,600 --> 00:37:48,880 Speaker 1: Now I'm just kidding, it's actually just Hans Geiger. Some 608 00:37:48,920 --> 00:37:53,640 Speaker 1: people actually call these devices Geiger Mueller counters, because another 609 00:37:53,719 --> 00:37:57,920 Speaker 1: guy named Valter Mueller took Geiger's design and tweaked it 610 00:37:58,000 --> 00:38:02,200 Speaker 1: a bit about two decades after the initial invention of 611 00:38:02,239 --> 00:38:05,520 Speaker 1: the Geiger counter to improve its performance. Some folks just 612 00:38:05,800 --> 00:38:09,880 Speaker 1: shorten this down to GM counters. But Hans Geiger was 613 00:38:09,920 --> 00:38:13,319 Speaker 1: a physicist who worked very closely with Ernest Rutherford, whom 614 00:38:13,320 --> 00:38:15,799 Speaker 1: I mentioned earlier as being the smarty pants who was 615 00:38:16,200 --> 00:38:20,480 Speaker 1: classifying radiation as alpha, beta, and gamma, and Geiger came 616 00:38:20,560 --> 00:38:23,560 Speaker 1: up with a device that initially was meant to detect 617 00:38:23,680 --> 00:38:26,839 Speaker 1: alpha particles. He would eventually expand it so he could 618 00:38:26,880 --> 00:38:29,960 Speaker 1: detect other types of radiation too, and he did it 619 00:38:30,000 --> 00:38:33,960 Speaker 1: with a pretty clever approach. Al Right, so I mentioned 620 00:38:34,000 --> 00:38:37,560 Speaker 1: that these types of radiation have enough energy to ionize 621 00:38:37,600 --> 00:38:42,560 Speaker 1: particles right to create electrically charged particles by stripping away electrons. 622 00:38:42,560 --> 00:38:45,560 Speaker 1: So ions have a net electrical charge there. It's either 623 00:38:45,680 --> 00:38:47,799 Speaker 1: positive or negative in general, but in this case we're 624 00:38:47,800 --> 00:38:51,640 Speaker 1: talking about positive ions. And the movement of electrically charged 625 00:38:51,680 --> 00:38:55,600 Speaker 1: particles has a name. It's electricity. That's what that is. 626 00:38:56,080 --> 00:38:59,160 Speaker 1: So thought Geiger. If I can create a device that 627 00:38:59,280 --> 00:39:03,360 Speaker 1: detects the presence of ions, then it stands to reason 628 00:39:03,640 --> 00:39:07,719 Speaker 1: that something in the area is causing these ions to 629 00:39:07,840 --> 00:39:12,360 Speaker 1: form something like radioactive material over time. Geiger counters, like 630 00:39:12,400 --> 00:39:14,160 Speaker 1: I said, would be able to detect all sorts of 631 00:39:14,160 --> 00:39:17,160 Speaker 1: different types of radiation, but initially it was all about 632 00:39:17,239 --> 00:39:20,960 Speaker 1: alpha radiation. And here's how it would work. A typical 633 00:39:21,080 --> 00:39:25,520 Speaker 1: Geiger counter has a meter that's connected to a wand 634 00:39:25,800 --> 00:39:28,719 Speaker 1: or tube. So the meter is your indicator. The meter 635 00:39:28,840 --> 00:39:30,799 Speaker 1: is what tells you if you get a hit, if 636 00:39:30,800 --> 00:39:36,440 Speaker 1: there's a spike that indicates radiation. Inside the tube or 637 00:39:36,440 --> 00:39:40,320 Speaker 1: the wand is a chamber, and inside the chamber is 638 00:39:40,360 --> 00:39:43,880 Speaker 1: a low pressure gas and typically there's a a window 639 00:39:44,280 --> 00:39:47,120 Speaker 1: made out of plastic on one side of this chamber. 640 00:39:48,200 --> 00:39:51,480 Speaker 1: Also in that same chamber with the low pressure gas 641 00:39:52,200 --> 00:39:55,280 Speaker 1: is a thin metal wire of tungsten. You can almost 642 00:39:55,320 --> 00:39:58,800 Speaker 1: think of it as like the filament on a light bulb, 643 00:39:59,520 --> 00:40:02,960 Speaker 1: and the fire runs to the end of the tube 644 00:40:03,000 --> 00:40:07,360 Speaker 1: that leads into the the cable that in turn attaches 645 00:40:07,400 --> 00:40:11,280 Speaker 1: to the meter, and at the end of that wire 646 00:40:11,600 --> 00:40:15,640 Speaker 1: there is an electrode with a high positive voltage. Now 647 00:40:15,680 --> 00:40:17,360 Speaker 1: the other end of the wire is not connected to 648 00:40:17,400 --> 00:40:22,560 Speaker 1: another contact. There's no complete circuit here, so you just 649 00:40:22,600 --> 00:40:28,040 Speaker 1: have a very high positive voltage on the wire. But 650 00:40:28,080 --> 00:40:31,600 Speaker 1: it creates an electric field between the metal wire and 651 00:40:31,640 --> 00:40:35,440 Speaker 1: the outside of the tube. So if the gas inside 652 00:40:35,680 --> 00:40:42,160 Speaker 1: the tube, this low pressure gas, encounters ionizing radiation, then 653 00:40:42,160 --> 00:40:46,359 Speaker 1: that radiation will strip electrons away from the gas molecules 654 00:40:46,480 --> 00:40:50,440 Speaker 1: inside the chamber. The stripped electrons, because of their negative charge, 655 00:40:50,960 --> 00:40:57,600 Speaker 1: will immediately zap the toungusten wire inside this one because 656 00:40:57,640 --> 00:41:01,800 Speaker 1: again we've applied a strong positive voltage to that wire. 657 00:41:02,239 --> 00:41:05,880 Speaker 1: So the electrons having the negative charge are attracted to 658 00:41:05,920 --> 00:41:09,280 Speaker 1: the positive charge of the tungsten wire. UH This usually 659 00:41:09,320 --> 00:41:12,600 Speaker 1: means that there's a big rush of electrons. As electrons 660 00:41:12,640 --> 00:41:15,200 Speaker 1: are moving, they will bash into other molecules, which will 661 00:41:15,239 --> 00:41:18,600 Speaker 1: strip over other electrons, so you'll get a quick zap. 662 00:41:18,840 --> 00:41:23,120 Speaker 1: Then you typically have to quench the Geiger counter, but 663 00:41:23,760 --> 00:41:25,920 Speaker 1: that really doesn't matter for the rest of this discussion. 664 00:41:25,960 --> 00:41:28,080 Speaker 1: I mean, it matters, but we're gonna focus on how 665 00:41:28,120 --> 00:41:31,640 Speaker 1: this is detecting things. So you get a bunch of 666 00:41:31,640 --> 00:41:35,240 Speaker 1: electrons that hit this tungsten wire that creates a pulse 667 00:41:35,320 --> 00:41:38,360 Speaker 1: of electricity, and the pulse is what feeds through a 668 00:41:38,400 --> 00:41:42,080 Speaker 1: cable that goes to the meter, and the meter registers 669 00:41:42,120 --> 00:41:44,480 Speaker 1: that there's been a pulse of electricity, which means that 670 00:41:44,560 --> 00:41:48,000 Speaker 1: there's been the generation of ions inside this chamber, which 671 00:41:48,000 --> 00:41:52,439 Speaker 1: in turn means you've encountered some sort of ionizing radiation. Uh. 672 00:41:52,520 --> 00:41:56,839 Speaker 1: The wire might also pass the signal through an amplifier. 673 00:41:57,400 --> 00:42:00,880 Speaker 1: The amplifier will increase the power of that signal and 674 00:42:00,960 --> 00:42:03,040 Speaker 1: send it to a loud speaker, and that's where you 675 00:42:03,080 --> 00:42:05,279 Speaker 1: get that clicking noise. So if you've ever seen a 676 00:42:05,280 --> 00:42:07,759 Speaker 1: movie where someone's using a Geiger counter and you're hearing 677 00:42:07,800 --> 00:42:11,480 Speaker 1: a series of clicks, that's because the idea is that 678 00:42:11,560 --> 00:42:15,440 Speaker 1: the wires picking up electric pulses due to ions, and 679 00:42:15,480 --> 00:42:17,560 Speaker 1: then that's being sent to a loud speakers, so that's 680 00:42:17,600 --> 00:42:21,600 Speaker 1: what's making the clicking noise. The beauty of this design 681 00:42:21,840 --> 00:42:26,239 Speaker 1: is that it isolates the ions source from the environment. 682 00:42:26,600 --> 00:42:30,200 Speaker 1: Right the source of the ions is this gas inside 683 00:42:30,200 --> 00:42:33,880 Speaker 1: a chamber. The gas is kept separate from the surrounding environment, 684 00:42:34,120 --> 00:42:37,760 Speaker 1: so you don't have to worry about somehow encountering ions 685 00:42:37,760 --> 00:42:40,480 Speaker 1: out in the wild, Like if you were standing next 686 00:42:40,520 --> 00:42:44,400 Speaker 1: to an ion generator. Let's say you've gotten ionization purifier, 687 00:42:44,520 --> 00:42:48,680 Speaker 1: something that's meant to purify the air in your room, 688 00:42:48,840 --> 00:42:52,160 Speaker 1: you shouldn't get a readoubt from your Geiger counter because 689 00:42:52,680 --> 00:42:56,719 Speaker 1: the ions being generated by this ionization chamber would not 690 00:42:56,840 --> 00:43:02,200 Speaker 1: be interacting with the gas inside the Geiger counters chamber. Instead, 691 00:43:02,480 --> 00:43:05,200 Speaker 1: the only time the gas and the Giger counter should 692 00:43:05,239 --> 00:43:08,960 Speaker 1: be ionizing at all is if you're coming into range 693 00:43:09,120 --> 00:43:14,799 Speaker 1: of ionizing radiation. So dependent upon the intensity of the 694 00:43:14,840 --> 00:43:17,839 Speaker 1: readelts you're getting, you would know kind of how much 695 00:43:17,960 --> 00:43:22,800 Speaker 1: radiation you were experiencing at any given moment. And again, 696 00:43:23,440 --> 00:43:26,640 Speaker 1: radiation exposure on its own does not immediately mean that 697 00:43:26,719 --> 00:43:30,680 Speaker 1: you mutate or you you know, suffer terrible injuries unless 698 00:43:30,719 --> 00:43:35,560 Speaker 1: it's an incredibly intense amount of radiation uh at very 699 00:43:35,600 --> 00:43:38,040 Speaker 1: high energies. But it does mean that you need to, 700 00:43:38,400 --> 00:43:41,439 Speaker 1: you know, get out of there and to find some 701 00:43:41,560 --> 00:43:45,000 Speaker 1: other place to be. One thing I didn't really talk 702 00:43:45,000 --> 00:43:48,520 Speaker 1: about in this episode was the concept of half life's 703 00:43:48,560 --> 00:43:51,799 Speaker 1: and that is important because half life's also give us 704 00:43:51,840 --> 00:43:57,840 Speaker 1: an idea of how long radioactive material could potentially remain dangerous. 705 00:43:57,840 --> 00:43:59,520 Speaker 1: And when you're looking at half lives that are on 706 00:43:59,600 --> 00:44:05,120 Speaker 1: thousands of years, you're talking about uh, time that extends 707 00:44:05,200 --> 00:44:09,520 Speaker 1: beyond that which humans have been on Earth right as 708 00:44:09,560 --> 00:44:12,440 Speaker 1: at least as human beings as we understand them, but 709 00:44:13,320 --> 00:44:16,000 Speaker 1: we might trace it back to an earlier evolutionary form 710 00:44:16,040 --> 00:44:19,080 Speaker 1: of humans. But you start looking at some of these 711 00:44:19,080 --> 00:44:21,799 Speaker 1: materials and you realize, wow, this stuff is going to 712 00:44:21,800 --> 00:44:25,759 Speaker 1: be radioactive for longer than humans have been walking around 713 00:44:25,760 --> 00:44:29,440 Speaker 1: on Earth as human beings. Uh. That's why you get 714 00:44:29,480 --> 00:44:33,200 Speaker 1: people who are concerned about things like nuclear power, where 715 00:44:33,640 --> 00:44:36,120 Speaker 1: one of the byproducts of nuclear power tends to be 716 00:44:36,360 --> 00:44:40,360 Speaker 1: nuclear waste that is radioactive. Some of that nuclear waste 717 00:44:40,600 --> 00:44:44,880 Speaker 1: will be radioactive and dangerously so for a relatively short time. 718 00:44:45,000 --> 00:44:48,959 Speaker 1: But there are other types of nuclear waste that will 719 00:44:49,040 --> 00:44:53,200 Speaker 1: be radioactive for a very long time and sure in 720 00:44:53,520 --> 00:44:56,879 Speaker 1: uh it's not emitting radiation at a level high enough 721 00:44:56,920 --> 00:45:00,640 Speaker 1: for it to you know, be dangerous if we don't 722 00:45:00,760 --> 00:45:05,160 Speaker 1: treat it carefully, but it's persistent and and long time 723 00:45:05,200 --> 00:45:08,520 Speaker 1: exposure to it will increase our risk of developing really 724 00:45:09,440 --> 00:45:14,520 Speaker 1: nasty diseases like cancer, So that's where that concern comes in. Now. 725 00:45:14,560 --> 00:45:17,280 Speaker 1: There are a lot of different approaches to nuclear power 726 00:45:17,360 --> 00:45:21,279 Speaker 1: to mitigate the creation of nuclear waste, and there are 727 00:45:21,280 --> 00:45:23,000 Speaker 1: a lot of plans on what to do with that 728 00:45:23,080 --> 00:45:26,240 Speaker 1: nuclear waste to try and keep it far enough away 729 00:45:26,239 --> 00:45:28,879 Speaker 1: from people to not be a problem, but that all 730 00:45:28,960 --> 00:45:32,040 Speaker 1: runs into a lot of other social issues that are 731 00:45:32,040 --> 00:45:36,640 Speaker 1: harder to solve than technical issues. Um. On the flip side, 732 00:45:36,640 --> 00:45:40,160 Speaker 1: we're also looking at possibilities like fusion power, which is 733 00:45:40,880 --> 00:45:45,759 Speaker 1: very different from the fission process that generates a lot 734 00:45:45,800 --> 00:45:50,600 Speaker 1: of nuclear waste, but those are topics for a different episode. 735 00:45:50,719 --> 00:45:54,120 Speaker 1: I hope you have a greater understanding of how radiation 736 00:45:54,200 --> 00:45:57,239 Speaker 1: works and what it actually means, as well as how 737 00:45:57,280 --> 00:45:59,719 Speaker 1: Geiger counters work. Again, I think it's a very elegant 738 00:45:59,760 --> 00:46:03,680 Speaker 1: way to try and detect radiation it's not so much 739 00:46:03,719 --> 00:46:07,759 Speaker 1: detecting the radiation directly, but rather the effects of radiation 740 00:46:08,440 --> 00:46:11,920 Speaker 1: on something that we can more easily observe directly. And 741 00:46:12,200 --> 00:46:15,520 Speaker 1: I think that's a very clever approach to uh to 742 00:46:16,200 --> 00:46:20,560 Speaker 1: creating a meter. If you guys have suggestions for future 743 00:46:20,680 --> 00:46:23,919 Speaker 1: episodes of tech Stuff, reach out to me and let 744 00:46:23,960 --> 00:46:28,320 Speaker 1: me know. On social media, the handle at both Twitter 745 00:46:28,400 --> 00:46:32,280 Speaker 1: and Facebook is exactly the same. That handle is text 746 00:46:32,320 --> 00:46:35,400 Speaker 1: stuff H s W and I'll talk to you again 747 00:46:36,239 --> 00:46:42,879 Speaker 1: really soon. Text Stuff is a production of I Heart 748 00:46:42,960 --> 00:46:46,360 Speaker 1: Radio's How Stuff Works. For more podcasts from I heart Radio, 749 00:46:46,680 --> 00:46:49,880 Speaker 1: visit the I heart Radio app, Apple Podcasts, or wherever 750 00:46:49,960 --> 00:46:51,480 Speaker 1: you listen to your favorite shows.