1 00:00:04,400 --> 00:00:07,800 Speaker 1: Welcome to tech Stuff, a production from I Heart Radio. 2 00:00:11,800 --> 00:00:14,200 Speaker 1: Hey there, and welcome to tech Stuff. I'm your host 3 00:00:14,280 --> 00:00:17,000 Speaker 1: Jonathan Strickland. I'm an executive producer with iHeart Radio and 4 00:00:17,040 --> 00:00:20,119 Speaker 1: How the tech are you Now. In a recent tech 5 00:00:20,200 --> 00:00:24,079 Speaker 1: News episode, I talked about how a Microsoft engineer named 6 00:00:24,239 --> 00:00:28,720 Speaker 1: Raymond Chen revealed that the music video for Janet Jackson's 7 00:00:29,840 --> 00:00:34,640 Speaker 1: hit Rhythm Nation was at one time the crasher of laptops, 8 00:00:35,000 --> 00:00:38,559 Speaker 1: or at least of certain laptops. Some folks discovered that 9 00:00:38,720 --> 00:00:42,320 Speaker 1: if they played this video on their laptop computer, or 10 00:00:42,520 --> 00:00:45,320 Speaker 1: if their laptop computer was close to something else that 11 00:00:45,400 --> 00:00:50,680 Speaker 1: was playing this music video, the computer would spontaneously crash. Now, 12 00:00:50,800 --> 00:00:54,560 Speaker 1: to be clear, these computers were not nasty, as miss 13 00:00:54,720 --> 00:00:58,880 Speaker 1: Jackson might say. They were not music critics. It turns 14 00:00:58,920 --> 00:01:03,800 Speaker 1: out that a sound played in that music video matched 15 00:01:03,880 --> 00:01:07,759 Speaker 1: the resonant frequency of the hard disk drives in these laptops, 16 00:01:08,120 --> 00:01:11,119 Speaker 1: though it took some time to suss that out. Chen 17 00:01:11,319 --> 00:01:14,440 Speaker 1: said that these were hard drives that we're spending at 18 00:01:14,440 --> 00:01:18,200 Speaker 1: five thousand four rpm. That's revolutions per minute, so going 19 00:01:18,200 --> 00:01:21,759 Speaker 1: around five thousand, four hundred times every minute. That's actually 20 00:01:22,160 --> 00:01:24,560 Speaker 1: on the lower end of what we typically see with 21 00:01:24,680 --> 00:01:27,080 Speaker 1: hard disk drives, they can top out at more than 22 00:01:27,160 --> 00:01:30,360 Speaker 1: twice as fast as that. But it's not bad. I mean, 23 00:01:30,400 --> 00:01:33,520 Speaker 1: you can still go out and buy a hard disk 24 00:01:33,600 --> 00:01:37,000 Speaker 1: drive today that's at five thousand PM. People typically like 25 00:01:37,600 --> 00:01:39,760 Speaker 1: faster ones. It means that you can read and write 26 00:01:39,840 --> 00:01:45,080 Speaker 1: information to such a hard drive faster. Anyway, the sound 27 00:01:45,120 --> 00:01:49,680 Speaker 1: from the music video was causing the hard drives to vibrate. 28 00:01:50,200 --> 00:01:53,960 Speaker 1: The platters inside would vibrate, and ultimately this would prompt 29 00:01:54,000 --> 00:01:57,360 Speaker 1: the computers to crash. So today I thought i'd talk 30 00:01:57,520 --> 00:02:00,160 Speaker 1: a little bit about hard drives, a bit of out 31 00:02:00,200 --> 00:02:03,480 Speaker 1: resonant frequencies, how a sound could cause a hard drive 32 00:02:03,520 --> 00:02:08,000 Speaker 1: to actually crash, and maybe talk about some myths surrounding resonance, 33 00:02:08,000 --> 00:02:12,680 Speaker 1: including one that I kind of perpetuated last week. So 34 00:02:13,040 --> 00:02:18,079 Speaker 1: I gotta hold myself up to a correction here anyway. 35 00:02:18,120 --> 00:02:20,920 Speaker 1: First up, if you were to take a hard drive apart, 36 00:02:21,400 --> 00:02:23,880 Speaker 1: don't do that, by the way, You're more than likely 37 00:02:23,880 --> 00:02:27,079 Speaker 1: going to destroy it. But you would see that inside 38 00:02:27,120 --> 00:02:31,399 Speaker 1: the hard disk drive you have a spindle, and on 39 00:02:31,440 --> 00:02:34,600 Speaker 1: the spindle would be at least one disc or platter. 40 00:02:34,919 --> 00:02:37,840 Speaker 1: More likely it would actually be more than one, perhaps 41 00:02:37,840 --> 00:02:41,040 Speaker 1: a stack of them, and each platter would be separated 42 00:02:41,200 --> 00:02:45,119 Speaker 1: from its neighbors by a small gap, and the platters 43 00:02:45,160 --> 00:02:48,280 Speaker 1: are kind of similar to a compact disk in some ways, 44 00:02:48,360 --> 00:02:52,680 Speaker 1: but compact discs store information that's read and written through 45 00:02:53,040 --> 00:02:57,960 Speaker 1: an optical drive. So with light laser specifically, hard disks 46 00:02:58,240 --> 00:03:03,800 Speaker 1: store information magneticle, not through optics. Now, this platter or 47 00:03:03,840 --> 00:03:08,480 Speaker 1: these platters are what spin inside a hard disk drive coding. 48 00:03:08,520 --> 00:03:12,359 Speaker 1: The platter is a thin layer of magnetic grains, so 49 00:03:13,560 --> 00:03:18,720 Speaker 1: using an electro magnetic head, the computer can write data 50 00:03:18,960 --> 00:03:24,000 Speaker 1: to the platter by realigning these magnetic grains so that 51 00:03:24,040 --> 00:03:28,320 Speaker 1: they point in a specific direction, essentially pointing magnetic north 52 00:03:28,400 --> 00:03:31,880 Speaker 1: or pointing magnetic south, and thus they can represent zeros 53 00:03:32,000 --> 00:03:36,000 Speaker 1: and ones. When the platter spins beneath the head or 54 00:03:36,240 --> 00:03:40,400 Speaker 1: above the head, depending on how this goes, and the 55 00:03:40,440 --> 00:03:44,160 Speaker 1: head is in passive mode, there's a little detector essentially 56 00:03:44,840 --> 00:03:48,080 Speaker 1: on the head that can pick up the magnetic fluctuations 57 00:03:48,520 --> 00:03:53,240 Speaker 1: from these aligned regions that are passing near it as 58 00:03:53,280 --> 00:03:56,800 Speaker 1: the disc is spinning, so it's being read now. The 59 00:03:56,840 --> 00:04:00,600 Speaker 1: head in this case can look a bit like tweezers 60 00:04:00,760 --> 00:04:04,000 Speaker 1: in a sense. There's typically a pair of arms, one 61 00:04:04,080 --> 00:04:07,040 Speaker 1: that goes over the top of the platter one that's beneath. 62 00:04:07,280 --> 00:04:10,600 Speaker 1: They are not making contact with the platter. In fact, 63 00:04:11,000 --> 00:04:13,640 Speaker 1: if they were to touch the platter, that would damage 64 00:04:13,720 --> 00:04:16,440 Speaker 1: the hard drive. You gotta keep in mind, these platters 65 00:04:16,440 --> 00:04:22,440 Speaker 1: are spinning super fast, so these electro magnets are separated 66 00:04:22,680 --> 00:04:25,720 Speaker 1: from the platters. They're not actually touching, they're they're hovering 67 00:04:25,760 --> 00:04:29,480 Speaker 1: above and below um. So really like every head is 68 00:04:29,560 --> 00:04:32,240 Speaker 1: usually a pair of red Wright heads. There's one on top, 69 00:04:32,320 --> 00:04:35,320 Speaker 1: one beneath each platter that allows the computer to store 70 00:04:35,360 --> 00:04:38,559 Speaker 1: information on either side of platters. And as I said, 71 00:04:38,720 --> 00:04:41,359 Speaker 1: your typical hard drive often has several of these platters 72 00:04:41,480 --> 00:04:44,240 Speaker 1: arranged in a stack, separated from each of them by 73 00:04:44,279 --> 00:04:47,560 Speaker 1: a small gap, and each platter has its own read 74 00:04:47,680 --> 00:04:51,320 Speaker 1: right head. But that is the super basic way that 75 00:04:51,440 --> 00:04:54,680 Speaker 1: hard drives work. I'm not even getting into things like 76 00:04:55,200 --> 00:04:58,320 Speaker 1: actually how you store a file on these platters, because 77 00:04:58,320 --> 00:05:00,640 Speaker 1: it's not as simple as like the roove on a 78 00:05:00,839 --> 00:05:03,840 Speaker 1: on a vinyl album representing a song. It's not like that. 79 00:05:04,600 --> 00:05:07,560 Speaker 1: But the reason for this rapid rotational speed is that 80 00:05:07,640 --> 00:05:10,200 Speaker 1: you do want to be able to read and write 81 00:05:10,240 --> 00:05:14,760 Speaker 1: information from this hard disk drive quickly. And you know, 82 00:05:15,000 --> 00:05:18,960 Speaker 1: if it didn't spin at these fast rates, it would 83 00:05:18,960 --> 00:05:21,880 Speaker 1: take forever, which is hyperbolie. It would take a really 84 00:05:21,880 --> 00:05:24,840 Speaker 1: long time for your computer to retrieve stored information from 85 00:05:24,880 --> 00:05:27,919 Speaker 1: the hard disk drive. And it blows my mind that 86 00:05:28,000 --> 00:05:32,359 Speaker 1: you can have platters spending times per minute or faster 87 00:05:32,920 --> 00:05:37,040 Speaker 1: and read or write information to those platters, storing gigabytes 88 00:05:37,080 --> 00:05:41,000 Speaker 1: of data in the process. Technology is really kind of 89 00:05:41,120 --> 00:05:46,800 Speaker 1: like magic, except you know it works. Now. If you 90 00:05:46,839 --> 00:05:50,120 Speaker 1: have a mechanical device like this, clearly everything needs to 91 00:05:50,160 --> 00:05:53,600 Speaker 1: be improper alignment or else you're going to have problems. 92 00:05:54,160 --> 00:05:57,080 Speaker 1: Jostling a hard disk drive can potentially knock a disc 93 00:05:57,160 --> 00:06:00,279 Speaker 1: off kilter, which would mean that once the spin doll 94 00:06:00,600 --> 00:06:03,479 Speaker 1: that the disks start on starts to spin, you're gonna 95 00:06:03,520 --> 00:06:07,520 Speaker 1: have some damage, possibly catastrophic damage. The platters need to 96 00:06:07,560 --> 00:06:12,160 Speaker 1: maintain both horizontal and vertical alignment, and honestly, knowing how 97 00:06:12,200 --> 00:06:14,880 Speaker 1: delicate a hard disk drive can be, I'm actually amazed 98 00:06:14,920 --> 00:06:17,599 Speaker 1: that my first ever MP three players survived for so 99 00:06:17,680 --> 00:06:20,800 Speaker 1: many years. I had a creative Zen device which had 100 00:06:20,800 --> 00:06:24,200 Speaker 1: a spinning hard disk drive inside of it, which is 101 00:06:24,240 --> 00:06:27,080 Speaker 1: a very tiny little hard drive, and I say I'm 102 00:06:27,120 --> 00:06:29,320 Speaker 1: amazed that survived because I know that thing took a 103 00:06:29,360 --> 00:06:32,080 Speaker 1: tumble more than once, and the impact could have been 104 00:06:32,200 --> 00:06:34,680 Speaker 1: enough to damage the hard drive, but I guess I 105 00:06:34,720 --> 00:06:38,719 Speaker 1: had more luck than brains anyway. According to a data 106 00:06:38,720 --> 00:06:44,200 Speaker 1: recovery firm called drive Savers, of hard disk drive failures 107 00:06:44,200 --> 00:06:48,000 Speaker 1: are the result of damage recording surfaces, typically created as 108 00:06:48,040 --> 00:06:51,479 Speaker 1: the result of a physical shock. Other potential causes for 109 00:06:51,520 --> 00:06:56,440 Speaker 1: failure include things like circuit board problems uh stiction, which 110 00:06:56,520 --> 00:07:00,560 Speaker 1: is the combination of friction and sticking, where if you 111 00:07:00,600 --> 00:07:02,400 Speaker 1: haven't used a hard des drive for a long time, 112 00:07:02,480 --> 00:07:05,640 Speaker 1: sometimes there can be this kind of friction sticking issue 113 00:07:05,880 --> 00:07:11,240 Speaker 1: that impedes the disks from spinning. And also drive motor failure, 114 00:07:11,280 --> 00:07:13,840 Speaker 1: which makes up like less than a percent of all 115 00:07:13,920 --> 00:07:17,720 Speaker 1: the hard disk drive failures. So usually the motor doesn't 116 00:07:17,840 --> 00:07:20,480 Speaker 1: isn't the problem. By the time the motor has given out, 117 00:07:20,520 --> 00:07:23,640 Speaker 1: something else has already failed in that hard disk. Now, 118 00:07:24,120 --> 00:07:26,320 Speaker 1: if something were to cause the hard drive to stop 119 00:07:26,360 --> 00:07:28,640 Speaker 1: spinning while it's in operation, you get a hard disk 120 00:07:28,680 --> 00:07:32,000 Speaker 1: drive failure in that prompts a full crash of the computer. 121 00:07:32,440 --> 00:07:36,240 Speaker 1: And this brings us to Janet or miss Jackson. If 122 00:07:36,280 --> 00:07:39,080 Speaker 1: I'm nasty, and it turns out that the song Rhythm 123 00:07:39,240 --> 00:07:43,240 Speaker 1: Nation has within it a frequency that resonates with a 124 00:07:43,280 --> 00:07:47,680 Speaker 1: certain popular model of hard disk drives from many years ago. 125 00:07:47,800 --> 00:07:50,680 Speaker 1: So this isn't really about current tech. We're actually talking 126 00:07:50,720 --> 00:07:54,600 Speaker 1: about machines that were sold around the year two thousand five. 127 00:07:55,160 --> 00:07:58,760 Speaker 1: So really kind of amazing that this even became a problem, 128 00:07:58,840 --> 00:08:03,440 Speaker 1: right because Rhythm Nation came out in nine, this particular 129 00:08:04,240 --> 00:08:08,920 Speaker 1: uh laptop that was prone to this kind of stuff, 130 00:08:09,000 --> 00:08:11,840 Speaker 1: or these laptops, I should say, because they all had 131 00:08:11,920 --> 00:08:14,400 Speaker 1: this hard drive in common. It wasn't the laptops fault. 132 00:08:14,800 --> 00:08:19,200 Speaker 1: Those were sold around two thousand five, and specifically, the 133 00:08:19,200 --> 00:08:21,840 Speaker 1: the sound frequency from the music video would resonate with 134 00:08:21,880 --> 00:08:25,240 Speaker 1: the natural resonant frequency produced by the hard drive when 135 00:08:25,280 --> 00:08:28,560 Speaker 1: the platter is spinning. So let's talk about frequency and 136 00:08:28,720 --> 00:08:33,800 Speaker 1: sound and resonance for a bit. With waves. Frequency refers 137 00:08:33,840 --> 00:08:36,840 Speaker 1: to the number of waves that pass a fixed point 138 00:08:37,240 --> 00:08:39,800 Speaker 1: within a given amount of time, and we use the 139 00:08:39,880 --> 00:08:44,319 Speaker 1: metric hurts to measure frequencies. So one hurts is equal 140 00:08:44,360 --> 00:08:48,319 Speaker 1: to one wave passing a fixed point in one second. 141 00:08:48,880 --> 00:08:52,240 Speaker 1: Two hurts would mean two waves would pass that point 142 00:08:52,640 --> 00:08:56,240 Speaker 1: in one second. Now, notice I didn't say sound waves 143 00:08:56,280 --> 00:08:59,680 Speaker 1: here because Hurts can refer to any kind of wave 144 00:08:59,800 --> 00:09:03,760 Speaker 1: or oscillation, so we can use frequency to talk about 145 00:09:03,760 --> 00:09:07,520 Speaker 1: stuff like light or sound or all sorts of other things. 146 00:09:07,559 --> 00:09:10,559 Speaker 1: But in this episode we're mostly concerned with sound. So 147 00:09:11,520 --> 00:09:14,720 Speaker 1: if you were to play the middle C on a piano, 148 00:09:15,080 --> 00:09:19,120 Speaker 1: and assuming that piano had been tuned according to VERD tuning, 149 00:09:19,360 --> 00:09:23,480 Speaker 1: which is not standard uh, the note would produce a 150 00:09:23,480 --> 00:09:27,680 Speaker 1: frequency of two hundred fifty six hurts. So that means 151 00:09:27,760 --> 00:09:31,480 Speaker 1: the sound wave travels at two hundred fifty six waves 152 00:09:31,880 --> 00:09:36,160 Speaker 1: past a given fixed point per second. Now, sound waves 153 00:09:36,320 --> 00:09:40,800 Speaker 1: are really vibrations, right. Physical vibrations is a physical phenomenon. 154 00:09:41,840 --> 00:09:44,920 Speaker 1: It is why there's no sound in space, because you 155 00:09:45,000 --> 00:09:51,320 Speaker 1: don't have stuff close enough to transmit vibration from one 156 00:09:51,400 --> 00:09:54,800 Speaker 1: thing to another, and you have to have stuff close 157 00:09:54,880 --> 00:09:58,440 Speaker 1: enough to vibrate and affect other things in order for 158 00:09:58,480 --> 00:10:02,040 Speaker 1: that to propagate for it to travel. Most of the 159 00:10:02,080 --> 00:10:06,520 Speaker 1: stuff we hear is traveling through the air, So in 160 00:10:06,559 --> 00:10:09,880 Speaker 1: this case, the vibrations we're talking about are typically these 161 00:10:09,960 --> 00:10:14,080 Speaker 1: little fluctuations in air pressure. You can kind of imagine 162 00:10:14,280 --> 00:10:18,000 Speaker 1: that these changes in air pressure are effectively pushing against 163 00:10:18,080 --> 00:10:22,280 Speaker 1: and pulling on your ear drum. Just slightly, which then 164 00:10:22,320 --> 00:10:27,319 Speaker 1: transmits those vibrations to our inner ear. Our brains ultimately 165 00:10:27,360 --> 00:10:31,600 Speaker 1: interpret this signal as sound, and the frequency at which 166 00:10:31,600 --> 00:10:34,960 Speaker 1: the air fluctuations affect our ear drums determines what pitch 167 00:10:35,120 --> 00:10:40,680 Speaker 1: we hear. So slower frequencies produce lower pitches. Faster frequencies 168 00:10:40,960 --> 00:10:47,160 Speaker 1: produce faster pitches. Two fifty six fluctuations like full fluctuations 169 00:10:47,160 --> 00:10:53,640 Speaker 1: per second produces middle C. Now, let's talk about resonant frequencies. 170 00:10:54,400 --> 00:10:57,800 Speaker 1: Systems have a frequency that they tend to oscillate at. 171 00:10:58,120 --> 00:11:01,400 Speaker 1: The reason middle C sounds like middle C is that 172 00:11:01,440 --> 00:11:03,880 Speaker 1: there is a string in that piano that's at the 173 00:11:04,000 --> 00:11:07,400 Speaker 1: right length and it's at the right tension to produce 174 00:11:07,960 --> 00:11:11,679 Speaker 1: that frequency. When that string is struck by a hammer, 175 00:11:11,920 --> 00:11:13,800 Speaker 1: when you push down on the key, a hammer strikes 176 00:11:13,840 --> 00:11:17,760 Speaker 1: the string and it vibrates at this frequency, and thus 177 00:11:17,800 --> 00:11:21,360 Speaker 1: we hear that middle C. Similarly, if you take a 178 00:11:21,400 --> 00:11:24,840 Speaker 1: wine glass and you tap the wine glass, you will 179 00:11:24,920 --> 00:11:28,640 Speaker 1: hear it ring out a tone. That tone is the 180 00:11:28,760 --> 00:11:32,560 Speaker 1: resonant frequency, the natural frequency for that glass. It's the 181 00:11:32,559 --> 00:11:36,880 Speaker 1: frequency at which it tends to oscillate naturally when struck. Now, 182 00:11:37,200 --> 00:11:41,200 Speaker 1: if you were to produce that same tone near the glass, 183 00:11:41,520 --> 00:11:44,600 Speaker 1: you would cause the glass to vibrate. You would induce 184 00:11:44,760 --> 00:11:48,240 Speaker 1: vibration in the glass. If you produce the tone with 185 00:11:48,400 --> 00:11:52,920 Speaker 1: enough volume or amplitude, if we're talking about waves, that 186 00:11:53,080 --> 00:11:56,280 Speaker 1: vibration can start to deform the glass enough to cause 187 00:11:56,320 --> 00:11:59,439 Speaker 1: the wine glass to shatter. And you've probably seen examples 188 00:11:59,480 --> 00:12:01,520 Speaker 1: of this, you know. The classic one is you have 189 00:12:01,559 --> 00:12:05,240 Speaker 1: an opera singer singing a clear note and holding a 190 00:12:05,280 --> 00:12:09,200 Speaker 1: wine glass and the glass inevitably breaks apart. That is 191 00:12:09,240 --> 00:12:11,680 Speaker 1: possible if you have someone with the lung power and 192 00:12:11,720 --> 00:12:15,160 Speaker 1: the singing ability to produce a strong enough sound at 193 00:12:15,160 --> 00:12:19,440 Speaker 1: the right frequency, but it ain't easy. In demonstrations and 194 00:12:19,520 --> 00:12:23,600 Speaker 1: physics classes, folks typically use a tone producer and an 195 00:12:23,600 --> 00:12:27,000 Speaker 1: amplifier and a speaker, which simplifies things, and it's also 196 00:12:27,440 --> 00:12:29,840 Speaker 1: safer than holding a glass close to your face while 197 00:12:29,840 --> 00:12:32,640 Speaker 1: trying to make it explode. You can also really dial 198 00:12:32,760 --> 00:12:36,600 Speaker 1: into the proper frequency, and you can kind of think 199 00:12:36,640 --> 00:12:38,760 Speaker 1: of this as being similar to pushing someone who is 200 00:12:38,800 --> 00:12:40,960 Speaker 1: swinging on a swing set. If you push at just 201 00:12:41,160 --> 00:12:44,880 Speaker 1: the right moment in their arc, you can really get 202 00:12:44,920 --> 00:12:48,319 Speaker 1: them to go higher without putting in too much effort 203 00:12:48,320 --> 00:12:50,400 Speaker 1: in your push but it does have to be at 204 00:12:50,440 --> 00:12:52,640 Speaker 1: just the right moment within the arc of the swing 205 00:12:52,720 --> 00:12:56,080 Speaker 1: to give a boost rather than interfere with the arc 206 00:12:56,160 --> 00:12:59,280 Speaker 1: of the swing. The sound waves are kind of giving 207 00:12:59,320 --> 00:13:01,679 Speaker 1: the glass of it just the right frequency for it 208 00:13:01,720 --> 00:13:05,480 Speaker 1: to oscillate and to keep oscillating. When we come back, 209 00:13:05,880 --> 00:13:08,360 Speaker 1: we'll talk about what this has to do with hard drives, 210 00:13:08,679 --> 00:13:12,000 Speaker 1: and we'll talk a bit more about some misconceptions about resonants, 211 00:13:12,000 --> 00:13:26,920 Speaker 1: including one that that I kind of talked about. Okay, 212 00:13:26,960 --> 00:13:31,120 Speaker 1: So Rhythm Nations music video had within the music video 213 00:13:31,160 --> 00:13:34,640 Speaker 1: a sound that was at a frequency that matched the 214 00:13:34,640 --> 00:13:38,520 Speaker 1: hard disk drives resonant frequency when it was spinning. So 215 00:13:40,040 --> 00:13:43,000 Speaker 1: if you were to play the Rhythm Nation music video 216 00:13:43,200 --> 00:13:46,080 Speaker 1: on one of these laptops, that sound would start to 217 00:13:46,880 --> 00:13:51,240 Speaker 1: push the platters on the hard disk drive at the 218 00:13:51,280 --> 00:13:53,920 Speaker 1: frequency that they were naturally going to vibrate at, so 219 00:13:54,240 --> 00:13:57,440 Speaker 1: they would start vibrating more and more, and that would 220 00:13:57,520 --> 00:14:01,040 Speaker 1: cause the hard disk drive to ash and the subsequent 221 00:14:01,040 --> 00:14:04,400 Speaker 1: computer crash. So how do you solve this problem? If 222 00:14:04,440 --> 00:14:07,480 Speaker 1: if hard disk drives are delicate, you know, that's why 223 00:14:07,480 --> 00:14:11,800 Speaker 1: they're in these very sturdy cases typically because they need 224 00:14:11,840 --> 00:14:15,960 Speaker 1: to be protected from everything else. Well, if they're so delicate, 225 00:14:16,000 --> 00:14:19,640 Speaker 1: how do you protect against this issue? Well, the hard 226 00:14:19,680 --> 00:14:22,320 Speaker 1: disk drive is a mechanical device, and everything has already 227 00:14:22,320 --> 00:14:24,880 Speaker 1: been engineered to work a specific way, so it's not 228 00:14:25,120 --> 00:14:28,120 Speaker 1: super easy to change the hard disk drive. You've already 229 00:14:28,120 --> 00:14:31,080 Speaker 1: sold all these laptops that have it in there. So 230 00:14:31,320 --> 00:14:34,280 Speaker 1: the solution was really to create a sound filter that 231 00:14:34,320 --> 00:14:39,720 Speaker 1: would mask the frequency, the resonant frequency. So essentially, this 232 00:14:39,800 --> 00:14:44,640 Speaker 1: filter would block laptops from playing that specific frequency. All 233 00:14:44,640 --> 00:14:47,400 Speaker 1: the other frequencies could play because they weren't going to 234 00:14:47,480 --> 00:14:51,640 Speaker 1: resonate with the hard disk, but this one wouldn't, and 235 00:14:51,800 --> 00:14:54,120 Speaker 1: chances are it was tough for human listeners to even 236 00:14:54,120 --> 00:14:56,240 Speaker 1: tell the difference, because being able to pick out a 237 00:14:56,280 --> 00:14:58,760 Speaker 1: specific frequency from a whole bunch of them in a 238 00:14:58,840 --> 00:15:02,240 Speaker 1: song is and something your average person can do. So 239 00:15:02,280 --> 00:15:05,160 Speaker 1: the thought was, yeah, this is technically going to have 240 00:15:05,200 --> 00:15:08,320 Speaker 1: an impact on certain media that contains this frequency, but 241 00:15:08,440 --> 00:15:10,000 Speaker 1: chances are no one's going to be able to tell 242 00:15:10,000 --> 00:15:13,520 Speaker 1: the difference anyway, and it won't matter if it's crashing computer, 243 00:15:13,640 --> 00:15:16,680 Speaker 1: So let's just block that from being able to play 244 00:15:16,720 --> 00:15:20,880 Speaker 1: on these kinds of laptops. So that filter saved the day. 245 00:15:20,920 --> 00:15:23,720 Speaker 1: But you could theoretically be working on your computer, and 246 00:15:23,720 --> 00:15:26,600 Speaker 1: the video for him Nation might play on some other device, 247 00:15:27,320 --> 00:15:31,480 Speaker 1: like say your home entertainment system. Presumably your home entertainment 248 00:15:31,480 --> 00:15:34,560 Speaker 1: system would not have this sound filter on it, so 249 00:15:34,960 --> 00:15:37,880 Speaker 1: your laptop might still crash because that frequency would be 250 00:15:37,920 --> 00:15:42,560 Speaker 1: present in that version of the music video. So one 251 00:15:42,560 --> 00:15:46,240 Speaker 1: reason I think Chen brought this up was that if 252 00:15:46,280 --> 00:15:48,760 Speaker 1: we forget about these things, if we forget about these 253 00:15:48,840 --> 00:15:54,360 Speaker 1: kinds of odd cases that require these patched solutions, then 254 00:15:54,400 --> 00:15:58,200 Speaker 1: we end up with stuff that's no longer really necessary. So, 255 00:15:58,240 --> 00:16:01,680 Speaker 1: like I said earlier, this regular problem was affecting machines 256 00:16:01,760 --> 00:16:05,480 Speaker 1: sold around two thousand five. The hard drives today are different, 257 00:16:05,520 --> 00:16:07,680 Speaker 1: and a lot of laptops don't even use hard disk 258 00:16:07,720 --> 00:16:11,320 Speaker 1: drives anymore. They use solid state drives, which don't have 259 00:16:11,320 --> 00:16:14,920 Speaker 1: any moving parts in them, And that means that filter 260 00:16:15,480 --> 00:16:19,080 Speaker 1: may not actually be necessary anymore. It might not be needed, 261 00:16:19,120 --> 00:16:22,120 Speaker 1: but it might still be in place on machines because 262 00:16:22,200 --> 00:16:25,000 Speaker 1: it was in earlier machines, and it ends up being 263 00:16:25,080 --> 00:16:30,120 Speaker 1: a carryover. So, in other words, something that was originally 264 00:16:30,440 --> 00:16:33,240 Speaker 1: put in place in order to fix a problem stays 265 00:16:33,280 --> 00:16:36,920 Speaker 1: in place because people haven't bothered to remove it. And 266 00:16:36,960 --> 00:16:39,280 Speaker 1: if we don't remember why we put something there to 267 00:16:39,360 --> 00:16:42,360 Speaker 1: begin with, we could just be living with stuff that 268 00:16:42,400 --> 00:16:46,080 Speaker 1: doesn't really do anything anymore, or that can can, at 269 00:16:46,160 --> 00:16:50,000 Speaker 1: least at some level impact our experience when we want 270 00:16:50,000 --> 00:16:53,440 Speaker 1: to jam out to Rhythm Nation. But let's talk about 271 00:16:53,440 --> 00:16:57,080 Speaker 1: some other residant frequency stories and myths, and let's start 272 00:16:57,160 --> 00:16:59,880 Speaker 1: with one I kind of whiffed on last week. So 273 00:17:00,240 --> 00:17:03,160 Speaker 1: I mentioned when first covering the story that subjecting something 274 00:17:03,160 --> 00:17:07,520 Speaker 1: to its resonant frequency can be quite destructive, as illustrated 275 00:17:07,600 --> 00:17:12,520 Speaker 1: by the wineglass demonstration that clearly shows that a resident 276 00:17:12,600 --> 00:17:18,480 Speaker 1: frequency can break something well. I also mentioned suspension bridges 277 00:17:18,760 --> 00:17:22,120 Speaker 1: in that particular news item, which I really should have 278 00:17:22,600 --> 00:17:25,119 Speaker 1: stopped to think about, because I already knew this was 279 00:17:25,160 --> 00:17:29,800 Speaker 1: not really relevant or correct, but for some reason to 280 00:17:29,840 --> 00:17:32,640 Speaker 1: just skip my mind. But I was referencing a real 281 00:17:32,680 --> 00:17:39,560 Speaker 1: world disaster that frequently is mentioned uh in concert with resonans, 282 00:17:40,000 --> 00:17:45,080 Speaker 1: but the actual cause of the destruction wasn't resonants. The 283 00:17:45,160 --> 00:17:49,120 Speaker 1: disaster in question was the collapse of the Tacoma Narrows 284 00:17:49,200 --> 00:17:53,280 Speaker 1: Bridge in the state of Washington in the United States. 285 00:17:53,320 --> 00:17:56,840 Speaker 1: So construction on this suspension bridge began in the nineteen thirties. 286 00:17:57,119 --> 00:17:59,919 Speaker 1: The finished project opened for traffic on July first night, 287 00:18:00,000 --> 00:18:04,439 Speaker 1: ten forty, and on November seven of that year we 288 00:18:04,560 --> 00:18:08,240 Speaker 1: got the collapse. So first, let's talk about what a 289 00:18:08,320 --> 00:18:13,760 Speaker 1: suspension bridge is. So it has advantages over your traditional 290 00:18:14,240 --> 00:18:18,160 Speaker 1: solid bridges that had, you know, multiple arcs of solid 291 00:18:18,200 --> 00:18:21,520 Speaker 1: material spanning whatever it is you're building the bridge across, 292 00:18:21,520 --> 00:18:24,240 Speaker 1: whether it's a chasm or river or a bay or 293 00:18:24,240 --> 00:18:27,199 Speaker 1: whatever it might be. One of the big advantages of 294 00:18:27,200 --> 00:18:30,080 Speaker 1: a suspension bridges that you need way less material to 295 00:18:30,119 --> 00:18:33,720 Speaker 1: make a suspension bridge than one of these traditional bridges were. 296 00:18:33,720 --> 00:18:35,600 Speaker 1: Really the only thing you have to worry about is 297 00:18:35,640 --> 00:18:38,600 Speaker 1: that the bridge is able to, you know, withstand the 298 00:18:38,600 --> 00:18:42,840 Speaker 1: gravitational force of it being pulled down, right. That's it. 299 00:18:43,160 --> 00:18:47,600 Speaker 1: Like otherwise they're pretty sturdy. Suspension bridges have other concerns. 300 00:18:47,760 --> 00:18:50,840 Speaker 1: Suspension bridges can be lighter, that can be less expensive 301 00:18:51,040 --> 00:18:54,879 Speaker 1: to build because you're using less material, and since the 302 00:18:54,920 --> 00:18:57,920 Speaker 1: public typically foots the bill for a construction of bridges, 303 00:18:58,560 --> 00:19:02,359 Speaker 1: making construction less spensive is a pretty high priority in 304 00:19:02,440 --> 00:19:06,960 Speaker 1: most projects. So a suspension bridge consists of two towers, 305 00:19:07,840 --> 00:19:10,800 Speaker 1: kind of like Tolkien, and these two towers are connected 306 00:19:10,840 --> 00:19:14,440 Speaker 1: to each other by cables. Those cables also extend further 307 00:19:14,920 --> 00:19:19,560 Speaker 1: to attached to either end of the bridged area. You 308 00:19:19,640 --> 00:19:24,240 Speaker 1: have rods that connect these cables to the bridges surface, 309 00:19:24,560 --> 00:19:27,720 Speaker 1: which is also known as the deck uh And so 310 00:19:27,760 --> 00:19:31,080 Speaker 1: the deck is suspended above whatever it is. The bridge 311 00:19:31,119 --> 00:19:33,399 Speaker 1: is crossing the chasm, the bay, the river, whatever it 312 00:19:33,480 --> 00:19:37,280 Speaker 1: might be. Thus we get suspension bridge. Now, the Tacoma 313 00:19:37,400 --> 00:19:41,399 Speaker 1: Narrows Bridge was the third longest suspension bridge at the 314 00:19:41,400 --> 00:19:45,000 Speaker 1: time of its construction, and in an effort to maximize 315 00:19:45,040 --> 00:19:49,720 Speaker 1: cost efficiency, the bridge was using plate girders along the 316 00:19:49,800 --> 00:19:53,520 Speaker 1: sides of the bridge to provide rigidity to the deck. Now, 317 00:19:53,560 --> 00:19:58,560 Speaker 1: typically instead of girders, you would use trusses, but trusses 318 00:19:58,560 --> 00:20:01,879 Speaker 1: would require more material and thus would have been more expensive, 319 00:20:01,920 --> 00:20:05,159 Speaker 1: So this was one of the considerations. One of the 320 00:20:05,160 --> 00:20:08,960 Speaker 1: the compromises made to have the bridge be less expensive 321 00:20:09,080 --> 00:20:11,639 Speaker 1: was to go with this model where you kind of 322 00:20:11,680 --> 00:20:15,360 Speaker 1: had this this ribbon like effect across the bridge as 323 00:20:15,400 --> 00:20:20,919 Speaker 1: opposed to trusses to make it more rigid. So this 324 00:20:21,000 --> 00:20:25,160 Speaker 1: compromise meant the bridge was more flexible than other suspension bridges. 325 00:20:25,240 --> 00:20:30,320 Speaker 1: Too flexible, you would say. Construction workers who were working 326 00:20:30,440 --> 00:20:33,040 Speaker 1: on building the darn thing referred to it as the 327 00:20:33,160 --> 00:20:37,240 Speaker 1: galloping Gurdie because of the girders and because well even 328 00:20:37,280 --> 00:20:39,399 Speaker 1: before the bridge opened, it was clear that the bridge 329 00:20:39,560 --> 00:20:43,919 Speaker 1: moved more than it necessarily should, at least under certain conditions. 330 00:20:44,440 --> 00:20:49,840 Speaker 1: So on November seven in Washington, the winds were in 331 00:20:49,920 --> 00:20:54,280 Speaker 1: high force, and as these high sustained winds were hitting 332 00:20:54,359 --> 00:20:59,120 Speaker 1: the suspension bridge, vorteses were forming. So when a fluid 333 00:20:59,640 --> 00:21:03,920 Speaker 1: hits a blunt object, vortices form as the fluid moves 334 00:21:04,000 --> 00:21:07,400 Speaker 1: around and then beyond the object. So if you could 335 00:21:07,440 --> 00:21:09,200 Speaker 1: see the wind, you would see it was creating this 336 00:21:09,280 --> 00:21:14,760 Speaker 1: sort of wiggly vortices behind the components that was hitting 337 00:21:14,760 --> 00:21:18,919 Speaker 1: on the bridge. And we were talking about some issues 338 00:21:18,920 --> 00:21:23,520 Speaker 1: with residents here. If those vibrations were at the right frequency, 339 00:21:23,600 --> 00:21:26,760 Speaker 1: then it starts to impart vibrations into the bridge itself 340 00:21:26,800 --> 00:21:28,919 Speaker 1: and the bridge begins to move up and down. And that, 341 00:21:29,000 --> 00:21:32,000 Speaker 1: in fact did happen, So there was at least some 342 00:21:32,119 --> 00:21:35,960 Speaker 1: movement of the bridge on November seven that related to residents. However, 343 00:21:37,480 --> 00:21:42,040 Speaker 1: that was not what caused the bridge to ultimately break 344 00:21:42,080 --> 00:21:46,479 Speaker 1: apart and collapse. So the bridge began to twist, not 345 00:21:46,560 --> 00:21:49,280 Speaker 1: just move up and down, but starting to twist along 346 00:21:49,320 --> 00:21:52,199 Speaker 1: its length, and that was really the problem, and that 347 00:21:52,240 --> 00:21:56,760 Speaker 1: twisting didn't come from residents. Instead, the wind was hitting 348 00:21:56,760 --> 00:22:00,760 Speaker 1: these girders along the side, and the vote disease that 349 00:22:00,840 --> 00:22:05,520 Speaker 1: we're forming, we're causing the bridge to move in a 350 00:22:05,560 --> 00:22:08,320 Speaker 1: specific way, like one side would move down, the other 351 00:22:08,359 --> 00:22:12,520 Speaker 1: side would move up. But then the bridge would try 352 00:22:12,600 --> 00:22:16,000 Speaker 1: to return back to its neutral position, you know, being level, 353 00:22:16,119 --> 00:22:18,800 Speaker 1: instead of being tilted to the left or to the right. 354 00:22:19,480 --> 00:22:22,600 Speaker 1: But when it would return, it would go beyond its 355 00:22:22,640 --> 00:22:26,320 Speaker 1: normal rest spot due to momentum, kind of like how 356 00:22:26,359 --> 00:22:29,320 Speaker 1: if you pluck a string, it actually moves beyond its 357 00:22:29,400 --> 00:22:32,880 Speaker 1: rest position when it when it uh when you let 358 00:22:32,880 --> 00:22:35,720 Speaker 1: it go. So the wind would then push on the 359 00:22:35,720 --> 00:22:39,080 Speaker 1: girders again as they had reached their other side, kind 360 00:22:39,119 --> 00:22:41,879 Speaker 1: of like you know, pushing someone on a swing. And 361 00:22:42,760 --> 00:22:47,400 Speaker 1: this introduced what engineers referred to as aero elastic flutter. 362 00:22:47,920 --> 00:22:49,359 Speaker 1: If you hold up a sheet of paper to the 363 00:22:49,359 --> 00:22:51,920 Speaker 1: wind and you see it like fluttering back and forth, 364 00:22:52,040 --> 00:22:55,080 Speaker 1: vibrating kind of in your hand, you can see an 365 00:22:55,080 --> 00:22:59,760 Speaker 1: example of aero elastic flutter. This is not resonance, it's 366 00:22:59,760 --> 00:23:04,600 Speaker 1: a separate phenomenon. So it ends up shaking up the bridge. 367 00:23:04,640 --> 00:23:07,680 Speaker 1: But it's not because it's at a resonant frequency. It's 368 00:23:07,720 --> 00:23:10,399 Speaker 1: because the wind is creating these war disease that are 369 00:23:10,440 --> 00:23:13,800 Speaker 1: putting additional pressures on the bridge and making it twist 370 00:23:13,840 --> 00:23:16,720 Speaker 1: back and forth. And you know, when you physically move 371 00:23:16,760 --> 00:23:19,840 Speaker 1: stuff like that, like if you're wiggling something over and 372 00:23:19,880 --> 00:23:22,719 Speaker 1: over and over again, you weaken it. And at around 373 00:23:22,760 --> 00:23:26,920 Speaker 1: eleven am, some concrete from the bridge structure broke loose 374 00:23:26,920 --> 00:23:29,960 Speaker 1: from the deck and fell down. Then a cable broke 375 00:23:30,160 --> 00:23:33,679 Speaker 1: and that drastically impacted stabilization, and it began to twist 376 00:23:33,720 --> 00:23:39,119 Speaker 1: even more violently, and eventually the bridge buckled and collapsed. 377 00:23:39,800 --> 00:23:42,719 Speaker 1: Reports say that at the peak of the twisting motion, 378 00:23:43,359 --> 00:23:45,399 Speaker 1: the sidewalk on one side, like the left side of 379 00:23:45,400 --> 00:23:48,320 Speaker 1: the bridge, would be nearly thirty feet higher than the 380 00:23:48,400 --> 00:23:51,879 Speaker 1: sidewalk on the opposite side of the bridge, like on 381 00:23:51,920 --> 00:23:55,119 Speaker 1: the right side. Um, as you were going down the bridge, 382 00:23:55,359 --> 00:23:59,560 Speaker 1: and that is terrifying to think of. Also, there's film 383 00:23:59,600 --> 00:24:02,640 Speaker 1: of the is happening. You can watch videos on YouTube 384 00:24:02,680 --> 00:24:06,280 Speaker 1: showing the twisting of the Tacoma Narrows Bridge and it 385 00:24:06,440 --> 00:24:10,560 Speaker 1: is dramatic to say the least. But as I said, 386 00:24:10,800 --> 00:24:15,679 Speaker 1: resonance ultimately did not play the major part of destruction 387 00:24:15,840 --> 00:24:19,879 Speaker 1: on that bridge. It did have an impact, but the 388 00:24:19,960 --> 00:24:26,240 Speaker 1: actual destruction came from these vortices and the arrow elastic flutter. Now, 389 00:24:26,280 --> 00:24:29,879 Speaker 1: when we come back, we'll talk about another mythical story 390 00:24:29,920 --> 00:24:34,320 Speaker 1: about residents and our good friend Nicola Tesla. But first 391 00:24:34,359 --> 00:24:47,600 Speaker 1: let's take a quick break Ah Tesla. Depending on what 392 00:24:47,720 --> 00:24:51,480 Speaker 1: circles you run in on the Internet, Tesla can either 393 00:24:51,600 --> 00:24:57,040 Speaker 1: be looked at as a very eccentric, tortured person who 394 00:24:57,680 --> 00:25:01,320 Speaker 1: had to struggle with mental health both issues for much 395 00:25:01,359 --> 00:25:04,080 Speaker 1: of his life and who got the raw end of 396 00:25:04,119 --> 00:25:07,439 Speaker 1: the deal on more than one occasion, but also was 397 00:25:08,280 --> 00:25:11,720 Speaker 1: a heck of a self promoter. Or you might see 398 00:25:11,760 --> 00:25:17,200 Speaker 1: him as an unimpeachable source of genius and innovation who 399 00:25:17,240 --> 00:25:21,879 Speaker 1: had come up with almost magical technologies that never manifested 400 00:25:21,880 --> 00:25:24,120 Speaker 1: but he totally had them in his head, like death 401 00:25:24,240 --> 00:25:28,679 Speaker 1: rays and stuff. Um. I tend to go on the 402 00:25:28,760 --> 00:25:32,680 Speaker 1: more modest side, uh and and I would never say 403 00:25:32,680 --> 00:25:36,679 Speaker 1: that Tesla was not a genius. He clearly was a genius, 404 00:25:37,480 --> 00:25:40,360 Speaker 1: but again he was a born self promoter. In fact, 405 00:25:40,400 --> 00:25:43,159 Speaker 1: I would say he was pretty darn similar to Thomas Edison, 406 00:25:43,480 --> 00:25:46,160 Speaker 1: in that regard, and a lot of folks kind of 407 00:25:46,200 --> 00:25:49,040 Speaker 1: referred to Thomas Edison as being lex luthor to Nick 408 00:25:49,119 --> 00:25:53,800 Speaker 1: Nicola Tesla's superman. Uh that there were two sides of 409 00:25:53,920 --> 00:25:57,639 Speaker 1: the same coin. Uh. I think that's being more than 410 00:25:57,680 --> 00:26:02,200 Speaker 1: a little melodramatic personally. But one thing Nikola Tesla experimented 411 00:26:02,280 --> 00:26:07,960 Speaker 1: with was an oscillating or reciprocating electric generator, and in 412 00:26:08,000 --> 00:26:11,160 Speaker 1: fact he got it to work. The principle was very 413 00:26:11,280 --> 00:26:14,200 Speaker 1: much sound. It's just that he found a better way 414 00:26:14,200 --> 00:26:17,080 Speaker 1: of accomplishing what his goal was, which was to create 415 00:26:18,240 --> 00:26:25,480 Speaker 1: a a sustained, consistent alternating current. So let's break this down. Now. 416 00:26:25,720 --> 00:26:27,719 Speaker 1: Imagine that you've got kind of like it looks kind 417 00:26:27,720 --> 00:26:31,879 Speaker 1: of like a metal post that's several inches long, maybe 418 00:26:32,160 --> 00:26:35,920 Speaker 1: you know, maybe up to a foot or maybe even bigger, uh, 419 00:26:35,960 --> 00:26:39,720 Speaker 1: and cylindrical in nature. Inside of that, you had a 420 00:26:39,800 --> 00:26:44,200 Speaker 1: chamber where there was a piston that could go up 421 00:26:44,200 --> 00:26:50,000 Speaker 1: and down the chamber cylinder. This piston would drive a 422 00:26:50,160 --> 00:26:54,439 Speaker 1: post like an iron core that had copper wire wrapped 423 00:26:54,440 --> 00:26:57,439 Speaker 1: around it, and this wire would connect to a circuit 424 00:26:57,440 --> 00:27:01,520 Speaker 1: of some sort and that would freely move up and 425 00:27:01,600 --> 00:27:05,879 Speaker 1: down the length of this one chamber based upon the 426 00:27:05,920 --> 00:27:11,240 Speaker 1: movements of this piston inside a cylinder. Now surrounding this 427 00:27:11,520 --> 00:27:15,120 Speaker 1: rod with copper coil on it was an electro magnet 428 00:27:15,880 --> 00:27:20,280 Speaker 1: connected to a battery. So a battery generates direct current. 429 00:27:20,720 --> 00:27:23,640 Speaker 1: That means the electricity always flows in the same direction 430 00:27:23,760 --> 00:27:27,600 Speaker 1: from uh, I mean, if you're talking about you're talking 431 00:27:27,640 --> 00:27:30,200 Speaker 1: about the way Benjamin Franklin thought of it. It goes 432 00:27:30,240 --> 00:27:33,479 Speaker 1: from positive to negative. The actual electrons go from negative 433 00:27:33,520 --> 00:27:36,000 Speaker 1: to positive. But you know, you you get what I'm saying, 434 00:27:36,080 --> 00:27:39,120 Speaker 1: So it always flows in that direction that cannot reverse 435 00:27:39,400 --> 00:27:45,120 Speaker 1: with direct current. So the electro magnet inside this piston 436 00:27:45,240 --> 00:27:49,920 Speaker 1: generator thing was acting just like a stationary permanent magnet was. 437 00:27:49,960 --> 00:27:52,400 Speaker 1: In fact, Tesla could have just put a very powerful 438 00:27:52,440 --> 00:27:54,639 Speaker 1: permanent magnet in this thing. It would have worked the 439 00:27:54,680 --> 00:27:59,000 Speaker 1: same way when you move a conductor through a stationary 440 00:27:59,080 --> 00:28:02,720 Speaker 1: magnetic field. So like you have a conductive material and 441 00:28:02,800 --> 00:28:06,680 Speaker 1: you pass it through a magnetic field that induces electricity 442 00:28:06,720 --> 00:28:11,200 Speaker 1: to flow within the conductor. You induce electric current by 443 00:28:11,200 --> 00:28:16,600 Speaker 1: moving the conductor up and down past this electric magnetic field. 444 00:28:16,680 --> 00:28:21,040 Speaker 1: Rather then you know, having this oscillating or reciprocating action 445 00:28:21,080 --> 00:28:24,399 Speaker 1: as the the coil moves up and down through this 446 00:28:24,400 --> 00:28:27,960 Speaker 1: this magnetic field. You actually have a similar effect as 447 00:28:28,000 --> 00:28:32,960 Speaker 1: if the magnetic field was fluctuating, was reversing its current 448 00:28:33,040 --> 00:28:35,719 Speaker 1: back and forth. So it's it's almost the same as 449 00:28:35,720 --> 00:28:40,120 Speaker 1: if the the coil were stationary, but the electro magnet 450 00:28:40,160 --> 00:28:43,160 Speaker 1: around it was powered by alternating current. Now, the reason 451 00:28:43,160 --> 00:28:46,360 Speaker 1: why this is important is that that would actually reverse 452 00:28:46,440 --> 00:28:51,560 Speaker 1: the flow of electricity through that coil. You generate alternating 453 00:28:51,640 --> 00:28:55,720 Speaker 1: current by moving this this coil up and down through 454 00:28:55,760 --> 00:28:59,040 Speaker 1: this magnetic field. So you take a direct current source 455 00:28:59,120 --> 00:29:04,560 Speaker 1: from the battery into this reciprocating electric generator, and by 456 00:29:04,600 --> 00:29:10,760 Speaker 1: moving this piston up and down, you can output alternating current. UH. 457 00:29:10,800 --> 00:29:13,440 Speaker 1: To provide the up and down power to move the coil, 458 00:29:13,920 --> 00:29:16,520 Speaker 1: we have to go to the piston. Now, in this 459 00:29:16,640 --> 00:29:21,440 Speaker 1: early invention, the piston was driven by steam power. Now, 460 00:29:21,480 --> 00:29:26,440 Speaker 1: I wish I could adequately describe Tesla's design here because 461 00:29:26,440 --> 00:29:30,240 Speaker 1: it really was genius. I mean, it was a beautiful 462 00:29:30,320 --> 00:29:33,959 Speaker 1: approach to creating a piston that can move up and 463 00:29:34,080 --> 00:29:38,080 Speaker 1: down be driven by steam, and it was beautifully simple 464 00:29:38,880 --> 00:29:42,960 Speaker 1: uh in design. However, to describe it is really hard 465 00:29:43,040 --> 00:29:45,680 Speaker 1: to do without visual aids. There are videos that You 466 00:29:45,720 --> 00:29:48,880 Speaker 1: can watch that show how this worked, and I recommend 467 00:29:48,960 --> 00:29:51,560 Speaker 1: you check it out if you want. But what you 468 00:29:51,600 --> 00:29:55,680 Speaker 1: need to know is that Tesla's piston served also as 469 00:29:55,680 --> 00:29:58,840 Speaker 1: a valve, and that valve controlled where steam could enter 470 00:29:59,000 --> 00:30:02,880 Speaker 1: an exit the cylinder that the piston was moving in. 471 00:30:03,280 --> 00:30:07,120 Speaker 1: So Tesla was using steam for both directions of the 472 00:30:07,160 --> 00:30:09,960 Speaker 1: stroke of the piston. So the upward and the downward 473 00:30:10,040 --> 00:30:12,680 Speaker 1: movements of the piston were driven by steam. Steam would 474 00:30:12,680 --> 00:30:16,080 Speaker 1: push the piston down, steam would push the piston back up, 475 00:30:16,520 --> 00:30:19,640 Speaker 1: and this would drive that coil to move up and 476 00:30:19,720 --> 00:30:24,480 Speaker 1: down the magnetic field further up inside the electric generator, 477 00:30:24,920 --> 00:30:28,960 Speaker 1: and thus the piston was providing the reciprocating motion. Now 478 00:30:29,040 --> 00:30:33,520 Speaker 1: let's get to resonance. So the story Tesla told is 479 00:30:33,560 --> 00:30:36,280 Speaker 1: that he was working in the lab late one night 480 00:30:36,320 --> 00:30:41,040 Speaker 1: when his eyes beheld an eerie sight because his reciprocating 481 00:30:41,080 --> 00:30:44,920 Speaker 1: electric generator or some oscillator that was similar to it 482 00:30:44,960 --> 00:30:48,600 Speaker 1: because it changes from story to story, was moving at 483 00:30:48,640 --> 00:30:54,000 Speaker 1: the same frequency as his buildings natural frequency. Some versions 484 00:30:54,000 --> 00:30:57,560 Speaker 1: of the story say that he had attached the piston 485 00:30:57,680 --> 00:31:01,040 Speaker 1: to a girder to provide stability, because obviously, if you 486 00:31:01,080 --> 00:31:03,840 Speaker 1: have something that's moving up and down rapidly. It's going 487 00:31:03,880 --> 00:31:05,800 Speaker 1: to be clattering all over the place unless you has 488 00:31:05,920 --> 00:31:09,600 Speaker 1: strap it down somewhere. So he was saying that he 489 00:31:09,680 --> 00:31:14,320 Speaker 1: was tuning in the resonance or the frequency rather of 490 00:31:14,360 --> 00:31:18,360 Speaker 1: this oscillator, so it resonated with the girder that it 491 00:31:18,400 --> 00:31:22,160 Speaker 1: was connected to within his building, and thus he began 492 00:31:22,240 --> 00:31:27,560 Speaker 1: to introduce increasingly violent vibrations into the building, and those 493 00:31:27,720 --> 00:31:30,760 Speaker 1: vibrations continue to build an intensity, and it led to 494 00:31:30,840 --> 00:31:34,240 Speaker 1: a small man made earthquake, leading a lot of people 495 00:31:34,640 --> 00:31:39,960 Speaker 1: to call this Tesla's earthquake machine. Then the story goes 496 00:31:40,000 --> 00:31:44,360 Speaker 1: that police and ambulances responded to the scene and they 497 00:31:44,360 --> 00:31:48,040 Speaker 1: got there justice Tesla was either taking a sledgehammer to 498 00:31:48,080 --> 00:31:50,720 Speaker 1: his generator to stop it from tearing the joint apart, 499 00:31:51,320 --> 00:31:53,960 Speaker 1: or that he had already stopped it and that he 500 00:31:54,000 --> 00:31:56,320 Speaker 1: was just playing coy and saying, oh, I didn't even 501 00:31:56,320 --> 00:32:00,880 Speaker 1: notice an earthquake. Now, could such a thing be possible? 502 00:32:02,400 --> 00:32:06,280 Speaker 1: Maybe you could theoretically create a reciprocating device and tune 503 00:32:06,320 --> 00:32:09,520 Speaker 1: it to a frequency that induces vibrations in a structure, 504 00:32:10,400 --> 00:32:13,560 Speaker 1: And theoretically you could maybe do one powerful enough that 505 00:32:13,680 --> 00:32:17,560 Speaker 1: ultimately it would start to cause damage. But We need 506 00:32:17,560 --> 00:32:21,040 Speaker 1: to keep several things in mind here. One is that 507 00:32:21,240 --> 00:32:26,640 Speaker 1: Tesla mostly told this story in his declining years. Uh. 508 00:32:26,880 --> 00:32:31,239 Speaker 1: The account I see most frequently cited comes from an 509 00:32:31,320 --> 00:32:37,600 Speaker 1: article that was published in nineteen on Tesla's seventy ninth birthday, 510 00:32:37,760 --> 00:32:43,120 Speaker 1: and that the actual shaking of the building was said 511 00:32:43,160 --> 00:32:47,200 Speaker 1: to have happened either in eighty seven or eight eight eight, 512 00:32:47,360 --> 00:32:50,120 Speaker 1: according to that article. So even that article doesn't get 513 00:32:50,160 --> 00:32:54,360 Speaker 1: specific on when this supposedly happened, and a different source 514 00:32:55,120 --> 00:33:00,240 Speaker 1: targets the the event to eight, so we don't even 515 00:33:00,240 --> 00:33:05,880 Speaker 1: have agreement of when this supposed earthquake happened. Tesla also 516 00:33:06,360 --> 00:33:09,960 Speaker 1: told other stories at that same party that are referenced 517 00:33:09,960 --> 00:33:12,400 Speaker 1: in the article I was mentioning, like the fact that 518 00:33:12,440 --> 00:33:15,520 Speaker 1: he had discovered cosmic radiation before anyone else did, he 519 00:33:15,560 --> 00:33:18,320 Speaker 1: just didn't think to tell anyone about it, and that 520 00:33:18,440 --> 00:33:21,840 Speaker 1: he found there are particles that traveled perhaps as much 521 00:33:21,880 --> 00:33:24,520 Speaker 1: as five times faster than the speed of light, which 522 00:33:24,680 --> 00:33:29,480 Speaker 1: just isn't true. So my point is that Tesla is 523 00:33:29,600 --> 00:33:33,440 Speaker 1: at best and unreliable source when it comes to stories 524 00:33:33,480 --> 00:33:38,240 Speaker 1: about his own work. In many ways, his life depended 525 00:33:38,320 --> 00:33:41,120 Speaker 1: upon his fame at this stage in his life he 526 00:33:41,200 --> 00:33:43,760 Speaker 1: was drifting from hotel to hotel in an effort to 527 00:33:43,800 --> 00:33:48,680 Speaker 1: avoid homelessness, and hotels would be happy to receive the 528 00:33:48,720 --> 00:33:52,360 Speaker 1: famous Tesla at least initially, but eventually his welcome would 529 00:33:52,360 --> 00:33:54,640 Speaker 1: wear out and he'd take the show on the road again. 530 00:33:55,040 --> 00:33:59,280 Speaker 1: So I have my doubts about Tesla's stories. At least 531 00:33:59,280 --> 00:34:02,800 Speaker 1: I doubt he was producing enough vibration to simulate an earthquake. 532 00:34:03,280 --> 00:34:05,719 Speaker 1: And I definitely doubt the versions that suggests that not 533 00:34:05,760 --> 00:34:09,839 Speaker 1: only was this building shaking, but that glass was bursting 534 00:34:09,920 --> 00:34:13,239 Speaker 1: from nearby buildings and that the road outside was quaking. 535 00:34:13,760 --> 00:34:16,480 Speaker 1: I don't believe that for a second. And one reason 536 00:34:16,520 --> 00:34:18,880 Speaker 1: I doubt this is that you've got a lot of 537 00:34:18,920 --> 00:34:23,160 Speaker 1: material and buildings that can have a dampening effect on vibrations. Right. 538 00:34:23,239 --> 00:34:29,160 Speaker 1: Not everything is contributing to this resonant frequency, this resonant oscillation. 539 00:34:29,640 --> 00:34:36,080 Speaker 1: Some stuff ends up resisting that and inhibiting that. And typically, 540 00:34:36,120 --> 00:34:40,279 Speaker 1: or usually, like the larger the thing you're trying to 541 00:34:40,280 --> 00:34:43,840 Speaker 1: to to vibrate, the larger the thing you're trying to 542 00:34:44,040 --> 00:34:47,919 Speaker 1: shake apart, the more force you need to really get 543 00:34:47,960 --> 00:34:50,840 Speaker 1: things going. In other words, if you walk up to 544 00:34:51,120 --> 00:34:54,160 Speaker 1: a building and you happen to know exactly how frequently 545 00:34:54,200 --> 00:34:57,480 Speaker 1: you need to tap on a girder to match the 546 00:34:58,000 --> 00:35:02,439 Speaker 1: frequency of that girder, and you do it. Uh yeah, 547 00:35:02,520 --> 00:35:04,960 Speaker 1: you're tapping at it, and you could probably feel those 548 00:35:05,040 --> 00:35:08,200 Speaker 1: vibrations along the length of the girder, but you're not 549 00:35:08,239 --> 00:35:11,000 Speaker 1: gonna force it to break apart. You'd have to use 550 00:35:11,040 --> 00:35:13,319 Speaker 1: more force than that. Pushing a kid at just the 551 00:35:13,400 --> 00:35:15,520 Speaker 1: right moment in the swings arc gives the kid a 552 00:35:15,520 --> 00:35:18,359 Speaker 1: significant boost, but you do have to push. You can't 553 00:35:18,400 --> 00:35:20,840 Speaker 1: just you know, like tap, it's not gonna do anything. 554 00:35:21,200 --> 00:35:24,560 Speaker 1: So the source of the vibrations have to produce waves 555 00:35:24,560 --> 00:35:28,399 Speaker 1: of significant amplitude to affect something like a building. Same 556 00:35:28,440 --> 00:35:31,560 Speaker 1: thing with the wine glass. Right, If you can produce 557 00:35:31,600 --> 00:35:34,920 Speaker 1: the right note, but you're not producing it at a 558 00:35:35,000 --> 00:35:38,560 Speaker 1: high enough volume, the glass won't break. It will vibrate. 559 00:35:39,320 --> 00:35:41,640 Speaker 1: If you put something like a piece of paper inside 560 00:35:41,640 --> 00:35:44,160 Speaker 1: the glass, you'll see the paper jump around because the 561 00:35:44,200 --> 00:35:47,360 Speaker 1: glass will be vibrating, but it won't be enough to 562 00:35:47,520 --> 00:35:51,320 Speaker 1: cause the glass to deform to the point where it breaks. 563 00:35:51,360 --> 00:35:55,719 Speaker 1: So I just doubt that Tesla's oscillator would be able 564 00:35:55,800 --> 00:35:58,200 Speaker 1: to do it, particularly the way he was describing it. 565 00:35:58,280 --> 00:36:01,880 Speaker 1: In his later descriptions of the technology, he said that 566 00:36:02,440 --> 00:36:06,200 Speaker 1: he had as an air powered one that could fit 567 00:36:06,239 --> 00:36:09,320 Speaker 1: in your pocket. So it was like a smaller version 568 00:36:10,080 --> 00:36:15,680 Speaker 1: of the oscillating electric generator. So technically, yes, I think 569 00:36:16,280 --> 00:36:18,920 Speaker 1: you could do this if you had something that was 570 00:36:19,040 --> 00:36:27,600 Speaker 1: significantly powerful enough to introduce vibrations that would ultimately cause destruction. 571 00:36:27,960 --> 00:36:32,520 Speaker 1: I just don't think Tesla's did it. I don't think so, 572 00:36:33,640 --> 00:36:36,160 Speaker 1: but I could be wrong. It's it's the hard thing 573 00:36:36,239 --> 00:36:39,840 Speaker 1: is that there just aren't any reliable sources outside of Tesla, 574 00:36:39,920 --> 00:36:43,040 Speaker 1: and Tesla was not a reliable source. He made a 575 00:36:43,080 --> 00:36:48,719 Speaker 1: lot of claims that have been unsubstantiated, and many of 576 00:36:48,760 --> 00:36:52,200 Speaker 1: them I believe were really meant to help keep him 577 00:36:52,320 --> 00:36:55,360 Speaker 1: in the public eye so that he could, you know, 578 00:36:55,680 --> 00:37:00,600 Speaker 1: live out his life with as little hardship as he could. Again, 579 00:37:01,360 --> 00:37:06,280 Speaker 1: he lived rather tortured existence, So no hard feelings against 580 00:37:06,280 --> 00:37:09,000 Speaker 1: the guy. He was just trying to get through life 581 00:37:09,840 --> 00:37:13,920 Speaker 1: under frustrating, to say the least circumstances. I mean, I 582 00:37:13,920 --> 00:37:17,000 Speaker 1: could go into the whole story about Tesla and Marconi. 583 00:37:17,040 --> 00:37:19,919 Speaker 1: If you think Tesla and Edison is one of those 584 00:37:19,960 --> 00:37:24,200 Speaker 1: big tales of two people, you know, posed against each other, 585 00:37:24,239 --> 00:37:27,560 Speaker 1: which really I would say Edison Westinghouse really is that story. 586 00:37:28,080 --> 00:37:31,839 Speaker 1: That's nothing compared to Marconi and and Tesla in my mind. 587 00:37:32,160 --> 00:37:35,040 Speaker 1: But that's the story for another time. Anyway, hope you 588 00:37:35,120 --> 00:37:39,240 Speaker 1: enjoyed this discussion about resonant frequencies and how a Janet 589 00:37:39,320 --> 00:37:43,560 Speaker 1: Jackson music video was shutting down computers left and right 590 00:37:43,560 --> 00:37:46,479 Speaker 1: in two thousand five. I found it interesting. I hope 591 00:37:46,520 --> 00:37:48,560 Speaker 1: you did too. If you would like me to cover 592 00:37:48,680 --> 00:37:51,200 Speaker 1: something specific on tech stuff, please reach out to me. 593 00:37:51,239 --> 00:37:52,960 Speaker 1: One way to do that is to download the I 594 00:37:53,040 --> 00:37:55,520 Speaker 1: Heart Radio app. It's free to download. You can navigate 595 00:37:55,560 --> 00:37:58,960 Speaker 1: over to tech Stuff, push little microphone icon, leave a 596 00:37:59,120 --> 00:38:01,719 Speaker 1: voice message up to thirty seconds in length and let 597 00:38:01,760 --> 00:38:04,280 Speaker 1: me know there. Or you can drop me a line 598 00:38:04,280 --> 00:38:07,040 Speaker 1: on Twitter to handle for the show is tech Stuff 599 00:38:07,239 --> 00:38:13,239 Speaker 1: H s W and I'll talk to you again really soon. Y. 600 00:38:17,520 --> 00:38:20,560 Speaker 1: Text Stuff is an I Heart Radio production. 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