August 24, 2022 • 38 mins
How could a music video's audio shutdown a computer? Why did the Tacoma Narrows bridge collapse in 1940? And did Nikola Tesla build an earthquake machine?
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Speaker 1 (00:04):
Welcome to tech Stuff, a production from I Heart Radio.
Hey there, and welcome to tech Stuff. I'm your host
Jonathan Strickland. I'm an executive producer with iHeart Radio and
How the tech are you Now. In a recent tech
News episode, I talked about how a Microsoft engineer named
Raymond Chen revealed that the music video for Janet Jackson's
(00:29):
hit Rhythm Nation was at one time the crasher of laptops,
or at least of certain laptops. Some folks discovered that
if they played this video on their laptop computer, or
if their laptop computer was close to something else that
was playing this music video, the computer would spontaneously crash. Now,
(00:50):
to be clear, these computers were not nasty, as miss
Jackson might say. They were not music critics. It turns
out that a sound played in that music video matched
the resonant frequency of the hard disk drives in these laptops,
though it took some time to suss that out. Chen
(01:11):
said that these were hard drives that we're spending at
five thousand four rpm. That's revolutions per minute, so going
around five thousand, four hundred times every minute. That's actually
on the lower end of what we typically see with
hard disk drives, they can top out at more than
twice as fast as that. But it's not bad. I mean,
you can still go out and buy a hard disk
(01:33):
drive today that's at five thousand PM. People typically like
faster ones. It means that you can read and write
information to such a hard drive faster. Anyway, the sound
from the music video was causing the hard drives to vibrate.
The platters inside would vibrate, and ultimately this would prompt
(01:54):
the computers to crash. So today I thought i'd talk
a little bit about hard drives, a bit of out
resonant frequencies, how a sound could cause a hard drive
to actually crash, and maybe talk about some myths surrounding resonance,
including one that I kind of perpetuated last week. So
I gotta hold myself up to a correction here anyway.
(02:18):
First up, if you were to take a hard drive apart,
don't do that, by the way, You're more than likely
going to destroy it. But you would see that inside
the hard disk drive you have a spindle, and on
the spindle would be at least one disc or platter.
More likely it would actually be more than one, perhaps
a stack of them, and each platter would be separated
(02:41):
from its neighbors by a small gap, and the platters
are kind of similar to a compact disk in some ways,
but compact discs store information that's read and written through
an optical drive. So with light laser specifically, hard disks
store information magneticle, not through optics. Now, this platter or
(03:03):
these platters are what spin inside a hard disk drive coding.
The platter is a thin layer of magnetic grains, so
using an electro magnetic head, the computer can write data
to the platter by realigning these magnetic grains so that
(03:24):
they point in a specific direction, essentially pointing magnetic north
or pointing magnetic south, and thus they can represent zeros
and ones. When the platter spins beneath the head or
above the head, depending on how this goes, and the
head is in passive mode, there's a little detector essentially
(03:44):
on the head that can pick up the magnetic fluctuations
from these aligned regions that are passing near it as
the disc is spinning, so it's being read now. The
head in this case can look a bit like tweezers
in a sense. There's typically a pair of arms, one
that goes over the top of the platter one that's beneath.
(04:07):
They are not making contact with the platter. In fact,
if they were to touch the platter, that would damage
the hard drive. You gotta keep in mind, these platters
are spinning super fast, so these electro magnets are separated
from the platters. They're not actually touching, they're they're hovering
above and below um. So really like every head is
(04:29):
usually a pair of red Wright heads. There's one on top,
one beneath each platter that allows the computer to store
information on either side of platters. And as I said,
your typical hard drive often has several of these platters
arranged in a stack, separated from each of them by
a small gap, and each platter has its own read
right head. But that is the super basic way that
(04:51):
hard drives work. I'm not even getting into things like
actually how you store a file on these platters, because
it's not as simple as like the roove on a
on a vinyl album representing a song. It's not like that.
But the reason for this rapid rotational speed is that
you do want to be able to read and write
information from this hard disk drive quickly. And you know,
(05:15):
if it didn't spin at these fast rates, it would
take forever, which is hyperbolie. It would take a really
long time for your computer to retrieve stored information from
the hard disk drive. And it blows my mind that
you can have platters spending times per minute or faster
and read or write information to those platters, storing gigabytes
(05:37):
of data in the process. Technology is really kind of
like magic, except you know it works. Now. If you
have a mechanical device like this, clearly everything needs to
be improper alignment or else you're going to have problems.
Jostling a hard disk drive can potentially knock a disc
(05:57):
off kilter, which would mean that once the spin doll
that the disks start on starts to spin, you're gonna
have some damage, possibly catastrophic damage. The platters need to
maintain both horizontal and vertical alignment, and honestly, knowing how
delicate a hard disk drive can be, I'm actually amazed
that my first ever MP three players survived for so
(06:17):
many years. I had a creative Zen device which had
a spinning hard disk drive inside of it, which is
a very tiny little hard drive, and I say I'm
amazed that survived because I know that thing took a
tumble more than once, and the impact could have been
enough to damage the hard drive, but I guess I
had more luck than brains anyway. According to a data
(06:38):
recovery firm called drive Savers, of hard disk drive failures
are the result of damage recording surfaces, typically created as
the result of a physical shock. Other potential causes for
failure include things like circuit board problems uh stiction, which
is the combination of friction and sticking, where if you
(07:00):
haven't used a hard des drive for a long time,
sometimes there can be this kind of friction sticking issue
that impedes the disks from spinning. And also drive motor failure,
which makes up like less than a percent of all
the hard disk drive failures. So usually the motor doesn't
isn't the problem. By the time the motor has given out,
something else has already failed in that hard disk. Now,
(07:24):
if something were to cause the hard drive to stop
spinning while it's in operation, you get a hard disk
drive failure in that prompts a full crash of the computer.
And this brings us to Janet or miss Jackson. If
I'm nasty, and it turns out that the song Rhythm
Nation has within it a frequency that resonates with a
certain popular model of hard disk drives from many years ago.
(07:47):
So this isn't really about current tech. We're actually talking
about machines that were sold around the year two thousand five.
So really kind of amazing that this even became a problem,
right because Rhythm Nation came out in nine, this particular
uh laptop that was prone to this kind of stuff,
(08:09):
or these laptops, I should say, because they all had
this hard drive in common. It wasn't the laptops fault.
Those were sold around two thousand five, and specifically, the
the sound frequency from the music video would resonate with
the natural resonant frequency produced by the hard drive when
the platter is spinning. So let's talk about frequency and
sound and resonance for a bit. With waves. Frequency refers
(08:33):
to the number of waves that pass a fixed point
within a given amount of time, and we use the
metric hurts to measure frequencies. So one hurts is equal
to one wave passing a fixed point in one second.
Two hurts would mean two waves would pass that point
in one second. Now, notice I didn't say sound waves
(08:56):
here because Hurts can refer to any kind of wave
or oscillation, so we can use frequency to talk about
stuff like light or sound or all sorts of other things.
But in this episode we're mostly concerned with sound. So
if you were to play the middle C on a piano,
and assuming that piano had been tuned according to VERD tuning,
(09:19):
which is not standard uh, the note would produce a
frequency of two hundred fifty six hurts. So that means
the sound wave travels at two hundred fifty six waves
past a given fixed point per second. Now, sound waves
are really vibrations, right. Physical vibrations is a physical phenomenon.
(09:41):
It is why there's no sound in space, because you
don't have stuff close enough to transmit vibration from one
thing to another, and you have to have stuff close
enough to vibrate and affect other things in order for
that to propagate for it to travel. Most of the
(10:02):
stuff we hear is traveling through the air, So in
this case, the vibrations we're talking about are typically these
little fluctuations in air pressure. You can kind of imagine
that these changes in air pressure are effectively pushing against
and pulling on your ear drum. Just slightly, which then
(10:22):
transmits those vibrations to our inner ear. Our brains ultimately
interpret this signal as sound, and the frequency at which
the air fluctuations affect our ear drums determines what pitch
we hear. So slower frequencies produce lower pitches. Faster frequencies
produce faster pitches. Two fifty six fluctuations like full fluctuations
(10:47):
per second produces middle C. Now, let's talk about resonant frequencies.
Systems have a frequency that they tend to oscillate at.
The reason middle C sounds like middle C is that
there is a string in that piano that's at the
right length and it's at the right tension to produce
(11:07):
that frequency. When that string is struck by a hammer,
when you push down on the key, a hammer strikes
the string and it vibrates at this frequency, and thus
we hear that middle C. Similarly, if you take a
wine glass and you tap the wine glass, you will
hear it ring out a tone. That tone is the
(11:28):
resonant frequency, the natural frequency for that glass. It's the
frequency at which it tends to oscillate naturally when struck. Now,
if you were to produce that same tone near the glass,
you would cause the glass to vibrate. You would induce
vibration in the glass. If you produce the tone with
enough volume or amplitude, if we're talking about waves, that
(11:53):
vibration can start to deform the glass enough to cause
the wine glass to shatter. And you've probably seen examples
of this, you know. The classic one is you have
an opera singer singing a clear note and holding a
wine glass and the glass inevitably breaks apart. That is
possible if you have someone with the lung power and
the singing ability to produce a strong enough sound at
(12:15):
the right frequency, but it ain't easy. In demonstrations and
physics classes, folks typically use a tone producer and an
amplifier and a speaker, which simplifies things, and it's also
safer than holding a glass close to your face while
trying to make it explode. You can also really dial
into the proper frequency, and you can kind of think
(12:36):
of this as being similar to pushing someone who is
swinging on a swing set. If you push at just
the right moment in their arc, you can really get
them to go higher without putting in too much effort
in your push but it does have to be at
just the right moment within the arc of the swing
to give a boost rather than interfere with the arc
of the swing. The sound waves are kind of giving
(12:59):
the glass of it just the right frequency for it
to oscillate and to keep oscillating. When we come back,
we'll talk about what this has to do with hard drives,
and we'll talk a bit more about some misconceptions about resonants,
including one that that I kind of talked about. Okay,
(13:26):
So Rhythm Nations music video had within the music video
a sound that was at a frequency that matched the
hard disk drives resonant frequency when it was spinning. So
if you were to play the Rhythm Nation music video
on one of these laptops, that sound would start to
push the platters on the hard disk drive at the
(13:51):
frequency that they were naturally going to vibrate at, so
they would start vibrating more and more, and that would
cause the hard disk drive to ash and the subsequent
computer crash. So how do you solve this problem? If
if hard disk drives are delicate, you know, that's why
they're in these very sturdy cases typically because they need
(14:11):
to be protected from everything else. Well, if they're so delicate,
how do you protect against this issue? Well, the hard
disk drive is a mechanical device, and everything has already
been engineered to work a specific way, so it's not
super easy to change the hard disk drive. You've already
sold all these laptops that have it in there. So
the solution was really to create a sound filter that
(14:34):
would mask the frequency, the resonant frequency. So essentially, this
filter would block laptops from playing that specific frequency. All
the other frequencies could play because they weren't going to
resonate with the hard disk, but this one wouldn't, and
chances are it was tough for human listeners to even
tell the difference, because being able to pick out a
(14:56):
specific frequency from a whole bunch of them in a
song is and something your average person can do. So
the thought was, yeah, this is technically going to have
an impact on certain media that contains this frequency, but
chances are no one's going to be able to tell
the difference anyway, and it won't matter if it's crashing computer,
So let's just block that from being able to play
(15:16):
on these kinds of laptops. So that filter saved the day.
But you could theoretically be working on your computer, and
the video for him Nation might play on some other device,
like say your home entertainment system. Presumably your home entertainment
system would not have this sound filter on it, so
your laptop might still crash because that frequency would be
(15:37):
present in that version of the music video. So one
reason I think Chen brought this up was that if
we forget about these things, if we forget about these
kinds of odd cases that require these patched solutions, then
we end up with stuff that's no longer really necessary. So,
(15:58):
like I said earlier, this regular problem was affecting machines
sold around two thousand five. The hard drives today are different,
and a lot of laptops don't even use hard disk
drives anymore. They use solid state drives, which don't have
any moving parts in them, And that means that filter
may not actually be necessary anymore. It might not be needed,
(16:19):
but it might still be in place on machines because
it was in earlier machines, and it ends up being
a carryover. So, in other words, something that was originally
put in place in order to fix a problem stays
in place because people haven't bothered to remove it. And
if we don't remember why we put something there to
(16:39):
begin with, we could just be living with stuff that
doesn't really do anything anymore, or that can can, at
least at some level impact our experience when we want
to jam out to Rhythm Nation. But let's talk about
some other residant frequency stories and myths, and let's start
with one I kind of whiffed on last week. So
(17:00):
I mentioned when first covering the story that subjecting something
to its resonant frequency can be quite destructive, as illustrated
by the wineglass demonstration that clearly shows that a resident
frequency can break something well. I also mentioned suspension bridges
in that particular news item, which I really should have
(17:22):
stopped to think about, because I already knew this was
not really relevant or correct, but for some reason to
just skip my mind. But I was referencing a real
world disaster that frequently is mentioned uh in concert with resonans,
but the actual cause of the destruction wasn't resonants. The
(17:45):
disaster in question was the collapse of the Tacoma Narrows
Bridge in the state of Washington in the United States.
So construction on this suspension bridge began in the nineteen thirties.
The finished project opened for traffic on July first night,
ten forty, and on November seven of that year we
got the collapse. So first, let's talk about what a
(18:08):
suspension bridge is. So it has advantages over your traditional
solid bridges that had, you know, multiple arcs of solid
material spanning whatever it is you're building the bridge across,
whether it's a chasm or river or a bay or
whatever it might be. One of the big advantages of
a suspension bridges that you need way less material to
(18:30):
make a suspension bridge than one of these traditional bridges were.
Really the only thing you have to worry about is
that the bridge is able to, you know, withstand the
gravitational force of it being pulled down, right. That's it.
Like otherwise they're pretty sturdy. Suspension bridges have other concerns.
Suspension bridges can be lighter, that can be less expensive
(18:51):
to build because you're using less material, and since the
public typically foots the bill for a construction of bridges,
making construction less spensive is a pretty high priority in
most projects. So a suspension bridge consists of two towers,
kind of like Tolkien, and these two towers are connected
to each other by cables. Those cables also extend further
(19:14):
to attached to either end of the bridged area. You
have rods that connect these cables to the bridges surface,
which is also known as the deck uh And so
the deck is suspended above whatever it is. The bridge
is crossing the chasm, the bay, the river, whatever it
might be. Thus we get suspension bridge. Now, the Tacoma
(19:37):
Narrows Bridge was the third longest suspension bridge at the
time of its construction, and in an effort to maximize
cost efficiency, the bridge was using plate girders along the
sides of the bridge to provide rigidity to the deck. Now,
typically instead of girders, you would use trusses, but trusses
(19:58):
would require more material and thus would have been more expensive,
So this was one of the considerations. One of the
the compromises made to have the bridge be less expensive
was to go with this model where you kind of
had this this ribbon like effect across the bridge as
opposed to trusses to make it more rigid. So this
(20:21):
compromise meant the bridge was more flexible than other suspension bridges.
Too flexible, you would say. Construction workers who were working
on building the darn thing referred to it as the
galloping Gurdie because of the girders and because well even
before the bridge opened, it was clear that the bridge
moved more than it necessarily should, at least under certain conditions.
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So on November seven in Washington, the winds were in
high force, and as these high sustained winds were hitting
the suspension bridge, vorteses were forming. So when a fluid
hits a blunt object, vortices form as the fluid moves
around and then beyond the object. So if you could
(21:07):
see the wind, you would see it was creating this
sort of wiggly vortices behind the components that was hitting
on the bridge. And we were talking about some issues
with residents here. If those vibrations were at the right frequency,
then it starts to impart vibrations into the bridge itself
and the bridge begins to move up and down. And that,
(21:29):
in fact did happen, So there was at least some
movement of the bridge on November seven that related to residents. However,
that was not what caused the bridge to ultimately break
apart and collapse. So the bridge began to twist, not
just move up and down, but starting to twist along
(21:49):
its length, and that was really the problem, and that
twisting didn't come from residents. Instead, the wind was hitting
these girders along the side, and the vote disease that
we're forming, we're causing the bridge to move in a
specific way, like one side would move down, the other
side would move up. But then the bridge would try
(22:12):
to return back to its neutral position, you know, being level,
instead of being tilted to the left or to the right.
But when it would return, it would go beyond its
normal rest spot due to momentum, kind of like how
if you pluck a string, it actually moves beyond its
rest position when it when it uh when you let
(22:32):
it go. So the wind would then push on the
girders again as they had reached their other side, kind
of like you know, pushing someone on a swing. And
this introduced what engineers referred to as aero elastic flutter.
If you hold up a sheet of paper to the
wind and you see it like fluttering back and forth,
vibrating kind of in your hand, you can see an
(22:55):
example of aero elastic flutter. This is not resonance, it's
a separate phenomenon. So it ends up shaking up the bridge.
But it's not because it's at a resonant frequency. It's
because the wind is creating these war disease that are
putting additional pressures on the bridge and making it twist
back and forth. And you know, when you physically move
(23:16):
stuff like that, like if you're wiggling something over and
over and over again, you weaken it. And at around
eleven am, some concrete from the bridge structure broke loose
from the deck and fell down. Then a cable broke
and that drastically impacted stabilization, and it began to twist
even more violently, and eventually the bridge buckled and collapsed.
(23:39):
Reports say that at the peak of the twisting motion,
the sidewalk on one side, like the left side of
the bridge, would be nearly thirty feet higher than the
sidewalk on the opposite side of the bridge, like on
the right side. Um, as you were going down the bridge,
and that is terrifying to think of. Also, there's film
of the is happening. You can watch videos on YouTube
(24:02):
showing the twisting of the Tacoma Narrows Bridge and it
is dramatic to say the least. But as I said,
resonance ultimately did not play the major part of destruction
on that bridge. It did have an impact, but the
actual destruction came from these vortices and the arrow elastic flutter. Now,
(24:26):
when we come back, we'll talk about another mythical story
about residents and our good friend Nicola Tesla. But first
let's take a quick break Ah Tesla. Depending on what
(24:47):
circles you run in on the Internet, Tesla can either
be looked at as a very eccentric, tortured person who
had to struggle with mental health both issues for much
of his life and who got the raw end of
the deal on more than one occasion, but also was
(25:08):
a heck of a self promoter. Or you might see
him as an unimpeachable source of genius and innovation who
had come up with almost magical technologies that never manifested
but he totally had them in his head, like death
rays and stuff. Um. I tend to go on the
(25:28):
more modest side, uh and and I would never say
that Tesla was not a genius. He clearly was a genius,
but again he was a born self promoter. In fact,
I would say he was pretty darn similar to Thomas Edison,
in that regard, and a lot of folks kind of
referred to Thomas Edison as being lex luthor to Nick
(25:49):
Nicola Tesla's superman. Uh that there were two sides of
the same coin. Uh. I think that's being more than
a little melodramatic personally. But one thing Nikola Tesla experimented
with was an oscillating or reciprocating electric generator, and in
fact he got it to work. The principle was very
(26:11):
much sound. It's just that he found a better way
of accomplishing what his goal was, which was to create
a a sustained, consistent alternating current. So let's break this down. Now.
Imagine that you've got kind of like it looks kind
of like a metal post that's several inches long, maybe
(26:32):
you know, maybe up to a foot or maybe even bigger, uh,
and cylindrical in nature. Inside of that, you had a
chamber where there was a piston that could go up
and down the chamber cylinder. This piston would drive a
post like an iron core that had copper wire wrapped
(26:54):
around it, and this wire would connect to a circuit
of some sort and that would freely move up and
down the length of this one chamber based upon the
movements of this piston inside a cylinder. Now surrounding this
rod with copper coil on it was an electro magnet
(27:15):
connected to a battery. So a battery generates direct current.
That means the electricity always flows in the same direction
from uh, I mean, if you're talking about you're talking
about the way Benjamin Franklin thought of it. It goes
from positive to negative. The actual electrons go from negative
to positive. But you know, you you get what I'm saying,
(27:36):
So it always flows in that direction that cannot reverse
with direct current. So the electro magnet inside this piston
generator thing was acting just like a stationary permanent magnet was.
In fact, Tesla could have just put a very powerful
permanent magnet in this thing. It would have worked the
same way when you move a conductor through a stationary
(27:59):
magnetic field. So like you have a conductive material and
you pass it through a magnetic field that induces electricity
to flow within the conductor. You induce electric current by
moving the conductor up and down past this electric magnetic field.
Rather then you know, having this oscillating or reciprocating action
(28:21):
as the the coil moves up and down through this
this magnetic field. You actually have a similar effect as
if the magnetic field was fluctuating, was reversing its current
back and forth. So it's it's almost the same as
if the the coil were stationary, but the electro magnet
around it was powered by alternating current. Now, the reason
(28:43):
why this is important is that that would actually reverse
the flow of electricity through that coil. You generate alternating
current by moving this this coil up and down through
this magnetic field. So you take a direct current source
from the battery into this reciprocating electric generator, and by
(29:04):
moving this piston up and down, you can output alternating current. UH.
To provide the up and down power to move the coil,
we have to go to the piston. Now, in this
early invention, the piston was driven by steam power. Now,
I wish I could adequately describe Tesla's design here because
(29:26):
it really was genius. I mean, it was a beautiful
approach to creating a piston that can move up and
down be driven by steam, and it was beautifully simple
uh in design. However, to describe it is really hard
to do without visual aids. There are videos that You
can watch that show how this worked, and I recommend
(29:48):
you check it out if you want. But what you
need to know is that Tesla's piston served also as
a valve, and that valve controlled where steam could enter
an exit the cylinder that the piston was moving in.
So Tesla was using steam for both directions of the
stroke of the piston. So the upward and the downward
(30:10):
movements of the piston were driven by steam. Steam would
push the piston down, steam would push the piston back up,
and this would drive that coil to move up and
down the magnetic field further up inside the electric generator,
and thus the piston was providing the reciprocating motion. Now
let's get to resonance. So the story Tesla told is
(30:33):
that he was working in the lab late one night
when his eyes beheld an eerie sight because his reciprocating
electric generator or some oscillator that was similar to it
because it changes from story to story, was moving at
the same frequency as his buildings natural frequency. Some versions
(30:54):
of the story say that he had attached the piston
to a girder to provide stability, because obviously, if you
have something that's moving up and down rapidly. It's going
to be clattering all over the place unless you has
strap it down somewhere. So he was saying that he
was tuning in the resonance or the frequency rather of
(31:14):
this oscillator, so it resonated with the girder that it
was connected to within his building, and thus he began
to introduce increasingly violent vibrations into the building, and those
vibrations continue to build an intensity, and it led to
a small man made earthquake, leading a lot of people
(31:34):
to call this Tesla's earthquake machine. Then the story goes
that police and ambulances responded to the scene and they
got there justice Tesla was either taking a sledgehammer to
his generator to stop it from tearing the joint apart,
or that he had already stopped it and that he
was just playing coy and saying, oh, I didn't even
(31:56):
notice an earthquake. Now, could such a thing be possible?
Maybe you could theoretically create a reciprocating device and tune
it to a frequency that induces vibrations in a structure,
And theoretically you could maybe do one powerful enough that
ultimately it would start to cause damage. But We need
(32:17):
to keep several things in mind here. One is that
Tesla mostly told this story in his declining years. Uh.
The account I see most frequently cited comes from an
article that was published in nineteen on Tesla's seventy ninth birthday,
(32:37):
and that the actual shaking of the building was said
to have happened either in eighty seven or eight eight eight,
according to that article. So even that article doesn't get
specific on when this supposedly happened, and a different source
targets the the event to eight, so we don't even
(33:00):
have agreement of when this supposed earthquake happened. Tesla also
told other stories at that same party that are referenced
in the article I was mentioning, like the fact that
he had discovered cosmic radiation before anyone else did, he
just didn't think to tell anyone about it, and that
he found there are particles that traveled perhaps as much
(33:21):
as five times faster than the speed of light, which
just isn't true. So my point is that Tesla is
at best and unreliable source when it comes to stories
about his own work. In many ways, his life depended
upon his fame at this stage in his life he
was drifting from hotel to hotel in an effort to
(33:43):
avoid homelessness, and hotels would be happy to receive the
famous Tesla at least initially, but eventually his welcome would
wear out and he'd take the show on the road again.
So I have my doubts about Tesla's stories. At least
I doubt he was producing enough vibration to simulate an earthquake.
And I definitely doubt the versions that suggests that not
(34:05):
only was this building shaking, but that glass was bursting
from nearby buildings and that the road outside was quaking.
I don't believe that for a second. And one reason
I doubt this is that you've got a lot of
material and buildings that can have a dampening effect on vibrations. Right.
Not everything is contributing to this resonant frequency, this resonant oscillation.
(34:29):
Some stuff ends up resisting that and inhibiting that. And typically,
or usually, like the larger the thing you're trying to
to to vibrate, the larger the thing you're trying to
shake apart, the more force you need to really get
things going. In other words, if you walk up to
(34:51):
a building and you happen to know exactly how frequently
you need to tap on a girder to match the
frequency of that girder, and you do it. Uh yeah,
you're tapping at it, and you could probably feel those
vibrations along the length of the girder, but you're not
gonna force it to break apart. You'd have to use
more force than that. Pushing a kid at just the
(35:13):
right moment in the swings arc gives the kid a
significant boost, but you do have to push. You can't
just you know, like tap, it's not gonna do anything.
So the source of the vibrations have to produce waves
of significant amplitude to affect something like a building. Same
thing with the wine glass. Right, If you can produce
the right note, but you're not producing it at a
(35:35):
high enough volume, the glass won't break. It will vibrate.
If you put something like a piece of paper inside
the glass, you'll see the paper jump around because the
glass will be vibrating, but it won't be enough to
cause the glass to deform to the point where it breaks.
So I just doubt that Tesla's oscillator would be able
(35:55):
to do it, particularly the way he was describing it.
In his later descriptions of the technology, he said that
he had as an air powered one that could fit
in your pocket. So it was like a smaller version
of the oscillating electric generator. So technically, yes, I think
(36:16):
you could do this if you had something that was
significantly powerful enough to introduce vibrations that would ultimately cause destruction.
I just don't think Tesla's did it. I don't think so,
but I could be wrong. It's it's the hard thing
is that there just aren't any reliable sources outside of Tesla,
(36:39):
and Tesla was not a reliable source. He made a
lot of claims that have been unsubstantiated, and many of
them I believe were really meant to help keep him
in the public eye so that he could, you know,
live out his life with as little hardship as he could. Again,
(37:01):
he lived rather tortured existence, So no hard feelings against
the guy. He was just trying to get through life
under frustrating, to say the least circumstances. I mean, I
could go into the whole story about Tesla and Marconi.
If you think Tesla and Edison is one of those
big tales of two people, you know, posed against each other,
(37:24):
which really I would say Edison Westinghouse really is that story.
That's nothing compared to Marconi and and Tesla in my mind.
But that's the story for another time. Anyway, hope you
enjoyed this discussion about resonant frequencies and how a Janet
Jackson music video was shutting down computers left and right
in two thousand five. I found it interesting. I hope
(37:46):
you did too. If you would like me to cover
something specific on tech stuff, please reach out to me.
One way to do that is to download the I
Heart Radio app. It's free to download. You can navigate
over to tech Stuff, push little microphone icon, leave a
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on Twitter to handle for the show is tech Stuff
(38:07):
H s W and I'll talk to you again really soon. Y.
Text Stuff is an I Heart Radio production. For more
podcasts from I Heart Radio, visit the i Heart Radio app,
Apple Podcasts, or wherever you listen to your favorite shows.
Welcome to tech Stuff, a production from I Heart Radio.
Hey there, and welcome to tech Stuff. I'm your host
Jonathan Strickland. I'm an executive producer with iHeart Radio and
How the tech are you Now. In a recent tech
News episode, I talked about how a Microsoft engineer named
Raymond Chen revealed that the music video for Janet Jackson's
(00:29):
hit Rhythm Nation was at one time the crasher of laptops,
or at least of certain laptops. Some folks discovered that
if they played this video on their laptop computer, or
if their laptop computer was close to something else that
was playing this music video, the computer would spontaneously crash. Now,
(00:50):
to be clear, these computers were not nasty, as miss
Jackson might say. They were not music critics. It turns
out that a sound played in that music video matched
the resonant frequency of the hard disk drives in these laptops,
though it took some time to suss that out. Chen
(01:11):
said that these were hard drives that we're spending at
five thousand four rpm. That's revolutions per minute, so going
around five thousand, four hundred times every minute. That's actually
on the lower end of what we typically see with
hard disk drives, they can top out at more than
twice as fast as that. But it's not bad. I mean,
you can still go out and buy a hard disk
(01:33):
drive today that's at five thousand PM. People typically like
faster ones. It means that you can read and write
information to such a hard drive faster. Anyway, the sound
from the music video was causing the hard drives to vibrate.
The platters inside would vibrate, and ultimately this would prompt
(01:54):
the computers to crash. So today I thought i'd talk
a little bit about hard drives, a bit of out
resonant frequencies, how a sound could cause a hard drive
to actually crash, and maybe talk about some myths surrounding resonance,
including one that I kind of perpetuated last week. So
I gotta hold myself up to a correction here anyway.
(02:18):
First up, if you were to take a hard drive apart,
don't do that, by the way, You're more than likely
going to destroy it. But you would see that inside
the hard disk drive you have a spindle, and on
the spindle would be at least one disc or platter.
More likely it would actually be more than one, perhaps
a stack of them, and each platter would be separated
(02:41):
from its neighbors by a small gap, and the platters
are kind of similar to a compact disk in some ways,
but compact discs store information that's read and written through
an optical drive. So with light laser specifically, hard disks
store information magneticle, not through optics. Now, this platter or
(03:03):
these platters are what spin inside a hard disk drive coding.
The platter is a thin layer of magnetic grains, so
using an electro magnetic head, the computer can write data
to the platter by realigning these magnetic grains so that
(03:24):
they point in a specific direction, essentially pointing magnetic north
or pointing magnetic south, and thus they can represent zeros
and ones. When the platter spins beneath the head or
above the head, depending on how this goes, and the
head is in passive mode, there's a little detector essentially
(03:44):
on the head that can pick up the magnetic fluctuations
from these aligned regions that are passing near it as
the disc is spinning, so it's being read now. The
head in this case can look a bit like tweezers
in a sense. There's typically a pair of arms, one
that goes over the top of the platter one that's beneath.
(04:07):
They are not making contact with the platter. In fact,
if they were to touch the platter, that would damage
the hard drive. You gotta keep in mind, these platters
are spinning super fast, so these electro magnets are separated
from the platters. They're not actually touching, they're they're hovering
above and below um. So really like every head is
(04:29):
usually a pair of red Wright heads. There's one on top,
one beneath each platter that allows the computer to store
information on either side of platters. And as I said,
your typical hard drive often has several of these platters
arranged in a stack, separated from each of them by
a small gap, and each platter has its own read
right head. But that is the super basic way that
(04:51):
hard drives work. I'm not even getting into things like
actually how you store a file on these platters, because
it's not as simple as like the roove on a
on a vinyl album representing a song. It's not like that.
But the reason for this rapid rotational speed is that
you do want to be able to read and write
information from this hard disk drive quickly. And you know,
(05:15):
if it didn't spin at these fast rates, it would
take forever, which is hyperbolie. It would take a really
long time for your computer to retrieve stored information from
the hard disk drive. And it blows my mind that
you can have platters spending times per minute or faster
and read or write information to those platters, storing gigabytes
(05:37):
of data in the process. Technology is really kind of
like magic, except you know it works. Now. If you
have a mechanical device like this, clearly everything needs to
be improper alignment or else you're going to have problems.
Jostling a hard disk drive can potentially knock a disc
(05:57):
off kilter, which would mean that once the spin doll
that the disks start on starts to spin, you're gonna
have some damage, possibly catastrophic damage. The platters need to
maintain both horizontal and vertical alignment, and honestly, knowing how
delicate a hard disk drive can be, I'm actually amazed
that my first ever MP three players survived for so
(06:17):
many years. I had a creative Zen device which had
a spinning hard disk drive inside of it, which is
a very tiny little hard drive, and I say I'm
amazed that survived because I know that thing took a
tumble more than once, and the impact could have been
enough to damage the hard drive, but I guess I
had more luck than brains anyway. According to a data
(06:38):
recovery firm called drive Savers, of hard disk drive failures
are the result of damage recording surfaces, typically created as
the result of a physical shock. Other potential causes for
failure include things like circuit board problems uh stiction, which
is the combination of friction and sticking, where if you
(07:00):
haven't used a hard des drive for a long time,
sometimes there can be this kind of friction sticking issue
that impedes the disks from spinning. And also drive motor failure,
which makes up like less than a percent of all
the hard disk drive failures. So usually the motor doesn't
isn't the problem. By the time the motor has given out,
something else has already failed in that hard disk. Now,
(07:24):
if something were to cause the hard drive to stop
spinning while it's in operation, you get a hard disk
drive failure in that prompts a full crash of the computer.
And this brings us to Janet or miss Jackson. If
I'm nasty, and it turns out that the song Rhythm
Nation has within it a frequency that resonates with a
certain popular model of hard disk drives from many years ago.
(07:47):
So this isn't really about current tech. We're actually talking
about machines that were sold around the year two thousand five.
So really kind of amazing that this even became a problem,
right because Rhythm Nation came out in nine, this particular
uh laptop that was prone to this kind of stuff,
(08:09):
or these laptops, I should say, because they all had
this hard drive in common. It wasn't the laptops fault.
Those were sold around two thousand five, and specifically, the
the sound frequency from the music video would resonate with
the natural resonant frequency produced by the hard drive when
the platter is spinning. So let's talk about frequency and
sound and resonance for a bit. With waves. Frequency refers
(08:33):
to the number of waves that pass a fixed point
within a given amount of time, and we use the
metric hurts to measure frequencies. So one hurts is equal
to one wave passing a fixed point in one second.
Two hurts would mean two waves would pass that point
in one second. Now, notice I didn't say sound waves
(08:56):
here because Hurts can refer to any kind of wave
or oscillation, so we can use frequency to talk about
stuff like light or sound or all sorts of other things.
But in this episode we're mostly concerned with sound. So
if you were to play the middle C on a piano,
and assuming that piano had been tuned according to VERD tuning,
(09:19):
which is not standard uh, the note would produce a
frequency of two hundred fifty six hurts. So that means
the sound wave travels at two hundred fifty six waves
past a given fixed point per second. Now, sound waves
are really vibrations, right. Physical vibrations is a physical phenomenon.
(09:41):
It is why there's no sound in space, because you
don't have stuff close enough to transmit vibration from one
thing to another, and you have to have stuff close
enough to vibrate and affect other things in order for
that to propagate for it to travel. Most of the
(10:02):
stuff we hear is traveling through the air, So in
this case, the vibrations we're talking about are typically these
little fluctuations in air pressure. You can kind of imagine
that these changes in air pressure are effectively pushing against
and pulling on your ear drum. Just slightly, which then
(10:22):
transmits those vibrations to our inner ear. Our brains ultimately
interpret this signal as sound, and the frequency at which
the air fluctuations affect our ear drums determines what pitch
we hear. So slower frequencies produce lower pitches. Faster frequencies
produce faster pitches. Two fifty six fluctuations like full fluctuations
(10:47):
per second produces middle C. Now, let's talk about resonant frequencies.
Systems have a frequency that they tend to oscillate at.
The reason middle C sounds like middle C is that
there is a string in that piano that's at the
right length and it's at the right tension to produce
(11:07):
that frequency. When that string is struck by a hammer,
when you push down on the key, a hammer strikes
the string and it vibrates at this frequency, and thus
we hear that middle C. Similarly, if you take a
wine glass and you tap the wine glass, you will
hear it ring out a tone. That tone is the
(11:28):
resonant frequency, the natural frequency for that glass. It's the
frequency at which it tends to oscillate naturally when struck. Now,
if you were to produce that same tone near the glass,
you would cause the glass to vibrate. You would induce
vibration in the glass. If you produce the tone with
enough volume or amplitude, if we're talking about waves, that
(11:53):
vibration can start to deform the glass enough to cause
the wine glass to shatter. And you've probably seen examples
of this, you know. The classic one is you have
an opera singer singing a clear note and holding a
wine glass and the glass inevitably breaks apart. That is
possible if you have someone with the lung power and
the singing ability to produce a strong enough sound at
(12:15):
the right frequency, but it ain't easy. In demonstrations and
physics classes, folks typically use a tone producer and an
amplifier and a speaker, which simplifies things, and it's also
safer than holding a glass close to your face while
trying to make it explode. You can also really dial
into the proper frequency, and you can kind of think
(12:36):
of this as being similar to pushing someone who is
swinging on a swing set. If you push at just
the right moment in their arc, you can really get
them to go higher without putting in too much effort
in your push but it does have to be at
just the right moment within the arc of the swing
to give a boost rather than interfere with the arc
of the swing. The sound waves are kind of giving
(12:59):
the glass of it just the right frequency for it
to oscillate and to keep oscillating. When we come back,
we'll talk about what this has to do with hard drives,
and we'll talk a bit more about some misconceptions about resonants,
including one that that I kind of talked about. Okay,
(13:26):
So Rhythm Nations music video had within the music video
a sound that was at a frequency that matched the
hard disk drives resonant frequency when it was spinning. So
if you were to play the Rhythm Nation music video
on one of these laptops, that sound would start to
push the platters on the hard disk drive at the
(13:51):
frequency that they were naturally going to vibrate at, so
they would start vibrating more and more, and that would
cause the hard disk drive to ash and the subsequent
computer crash. So how do you solve this problem? If
if hard disk drives are delicate, you know, that's why
they're in these very sturdy cases typically because they need
(14:11):
to be protected from everything else. Well, if they're so delicate,
how do you protect against this issue? Well, the hard
disk drive is a mechanical device, and everything has already
been engineered to work a specific way, so it's not
super easy to change the hard disk drive. You've already
sold all these laptops that have it in there. So
the solution was really to create a sound filter that
(14:34):
would mask the frequency, the resonant frequency. So essentially, this
filter would block laptops from playing that specific frequency. All
the other frequencies could play because they weren't going to
resonate with the hard disk, but this one wouldn't, and
chances are it was tough for human listeners to even
tell the difference, because being able to pick out a
(14:56):
specific frequency from a whole bunch of them in a
song is and something your average person can do. So
the thought was, yeah, this is technically going to have
an impact on certain media that contains this frequency, but
chances are no one's going to be able to tell
the difference anyway, and it won't matter if it's crashing computer,
So let's just block that from being able to play
(15:16):
on these kinds of laptops. So that filter saved the day.
But you could theoretically be working on your computer, and
the video for him Nation might play on some other device,
like say your home entertainment system. Presumably your home entertainment
system would not have this sound filter on it, so
your laptop might still crash because that frequency would be
(15:37):
present in that version of the music video. So one
reason I think Chen brought this up was that if
we forget about these things, if we forget about these
kinds of odd cases that require these patched solutions, then
we end up with stuff that's no longer really necessary. So,
(15:58):
like I said earlier, this regular problem was affecting machines
sold around two thousand five. The hard drives today are different,
and a lot of laptops don't even use hard disk
drives anymore. They use solid state drives, which don't have
any moving parts in them, And that means that filter
may not actually be necessary anymore. It might not be needed,
(16:19):
but it might still be in place on machines because
it was in earlier machines, and it ends up being
a carryover. So, in other words, something that was originally
put in place in order to fix a problem stays
in place because people haven't bothered to remove it. And
if we don't remember why we put something there to
(16:39):
begin with, we could just be living with stuff that
doesn't really do anything anymore, or that can can, at
least at some level impact our experience when we want
to jam out to Rhythm Nation. But let's talk about
some other residant frequency stories and myths, and let's start
with one I kind of whiffed on last week. So
(17:00):
I mentioned when first covering the story that subjecting something
to its resonant frequency can be quite destructive, as illustrated
by the wineglass demonstration that clearly shows that a resident
frequency can break something well. I also mentioned suspension bridges
in that particular news item, which I really should have
(17:22):
stopped to think about, because I already knew this was
not really relevant or correct, but for some reason to
just skip my mind. But I was referencing a real
world disaster that frequently is mentioned uh in concert with resonans,
but the actual cause of the destruction wasn't resonants. The
(17:45):
disaster in question was the collapse of the Tacoma Narrows
Bridge in the state of Washington in the United States.
So construction on this suspension bridge began in the nineteen thirties.
The finished project opened for traffic on July first night,
ten forty, and on November seven of that year we
got the collapse. So first, let's talk about what a
(18:08):
suspension bridge is. So it has advantages over your traditional
solid bridges that had, you know, multiple arcs of solid
material spanning whatever it is you're building the bridge across,
whether it's a chasm or river or a bay or
whatever it might be. One of the big advantages of
a suspension bridges that you need way less material to
(18:30):
make a suspension bridge than one of these traditional bridges were.
Really the only thing you have to worry about is
that the bridge is able to, you know, withstand the
gravitational force of it being pulled down, right. That's it.
Like otherwise they're pretty sturdy. Suspension bridges have other concerns.
Suspension bridges can be lighter, that can be less expensive
(18:51):
to build because you're using less material, and since the
public typically foots the bill for a construction of bridges,
making construction less spensive is a pretty high priority in
most projects. So a suspension bridge consists of two towers,
kind of like Tolkien, and these two towers are connected
to each other by cables. Those cables also extend further
(19:14):
to attached to either end of the bridged area. You
have rods that connect these cables to the bridges surface,
which is also known as the deck uh And so
the deck is suspended above whatever it is. The bridge
is crossing the chasm, the bay, the river, whatever it
might be. Thus we get suspension bridge. Now, the Tacoma
(19:37):
Narrows Bridge was the third longest suspension bridge at the
time of its construction, and in an effort to maximize
cost efficiency, the bridge was using plate girders along the
sides of the bridge to provide rigidity to the deck. Now,
typically instead of girders, you would use trusses, but trusses
(19:58):
would require more material and thus would have been more expensive,
So this was one of the considerations. One of the
the compromises made to have the bridge be less expensive
was to go with this model where you kind of
had this this ribbon like effect across the bridge as
opposed to trusses to make it more rigid. So this
(20:21):
compromise meant the bridge was more flexible than other suspension bridges.
Too flexible, you would say. Construction workers who were working
on building the darn thing referred to it as the
galloping Gurdie because of the girders and because well even
before the bridge opened, it was clear that the bridge
moved more than it necessarily should, at least under certain conditions.
(20:44):
So on November seven in Washington, the winds were in
high force, and as these high sustained winds were hitting
the suspension bridge, vorteses were forming. So when a fluid
hits a blunt object, vortices form as the fluid moves
around and then beyond the object. So if you could
(21:07):
see the wind, you would see it was creating this
sort of wiggly vortices behind the components that was hitting
on the bridge. And we were talking about some issues
with residents here. If those vibrations were at the right frequency,
then it starts to impart vibrations into the bridge itself
and the bridge begins to move up and down. And that,
(21:29):
in fact did happen, So there was at least some
movement of the bridge on November seven that related to residents. However,
that was not what caused the bridge to ultimately break
apart and collapse. So the bridge began to twist, not
just move up and down, but starting to twist along
(21:49):
its length, and that was really the problem, and that
twisting didn't come from residents. Instead, the wind was hitting
these girders along the side, and the vote disease that
we're forming, we're causing the bridge to move in a
specific way, like one side would move down, the other
side would move up. But then the bridge would try
(22:12):
to return back to its neutral position, you know, being level,
instead of being tilted to the left or to the right.
But when it would return, it would go beyond its
normal rest spot due to momentum, kind of like how
if you pluck a string, it actually moves beyond its
rest position when it when it uh when you let
(22:32):
it go. So the wind would then push on the
girders again as they had reached their other side, kind
of like you know, pushing someone on a swing. And
this introduced what engineers referred to as aero elastic flutter.
If you hold up a sheet of paper to the
wind and you see it like fluttering back and forth,
vibrating kind of in your hand, you can see an
(22:55):
example of aero elastic flutter. This is not resonance, it's
a separate phenomenon. So it ends up shaking up the bridge.
But it's not because it's at a resonant frequency. It's
because the wind is creating these war disease that are
putting additional pressures on the bridge and making it twist
back and forth. And you know, when you physically move
(23:16):
stuff like that, like if you're wiggling something over and
over and over again, you weaken it. And at around
eleven am, some concrete from the bridge structure broke loose
from the deck and fell down. Then a cable broke
and that drastically impacted stabilization, and it began to twist
even more violently, and eventually the bridge buckled and collapsed.
(23:39):
Reports say that at the peak of the twisting motion,
the sidewalk on one side, like the left side of
the bridge, would be nearly thirty feet higher than the
sidewalk on the opposite side of the bridge, like on
the right side. Um, as you were going down the bridge,
and that is terrifying to think of. Also, there's film
of the is happening. You can watch videos on YouTube
(24:02):
showing the twisting of the Tacoma Narrows Bridge and it
is dramatic to say the least. But as I said,
resonance ultimately did not play the major part of destruction
on that bridge. It did have an impact, but the
actual destruction came from these vortices and the arrow elastic flutter. Now,
(24:26):
when we come back, we'll talk about another mythical story
about residents and our good friend Nicola Tesla. But first
let's take a quick break Ah Tesla. Depending on what
(24:47):
circles you run in on the Internet, Tesla can either
be looked at as a very eccentric, tortured person who
had to struggle with mental health both issues for much
of his life and who got the raw end of
the deal on more than one occasion, but also was
(25:08):
a heck of a self promoter. Or you might see
him as an unimpeachable source of genius and innovation who
had come up with almost magical technologies that never manifested
but he totally had them in his head, like death
rays and stuff. Um. I tend to go on the
(25:28):
more modest side, uh and and I would never say
that Tesla was not a genius. He clearly was a genius,
but again he was a born self promoter. In fact,
I would say he was pretty darn similar to Thomas Edison,
in that regard, and a lot of folks kind of
referred to Thomas Edison as being lex luthor to Nick
(25:49):
Nicola Tesla's superman. Uh that there were two sides of
the same coin. Uh. I think that's being more than
a little melodramatic personally. But one thing Nikola Tesla experimented
with was an oscillating or reciprocating electric generator, and in
fact he got it to work. The principle was very
(26:11):
much sound. It's just that he found a better way
of accomplishing what his goal was, which was to create
a a sustained, consistent alternating current. So let's break this down. Now.
Imagine that you've got kind of like it looks kind
of like a metal post that's several inches long, maybe
(26:32):
you know, maybe up to a foot or maybe even bigger, uh,
and cylindrical in nature. Inside of that, you had a
chamber where there was a piston that could go up
and down the chamber cylinder. This piston would drive a
post like an iron core that had copper wire wrapped
(26:54):
around it, and this wire would connect to a circuit
of some sort and that would freely move up and
down the length of this one chamber based upon the
movements of this piston inside a cylinder. Now surrounding this
rod with copper coil on it was an electro magnet
(27:15):
connected to a battery. So a battery generates direct current.
That means the electricity always flows in the same direction
from uh, I mean, if you're talking about you're talking
about the way Benjamin Franklin thought of it. It goes
from positive to negative. The actual electrons go from negative
to positive. But you know, you you get what I'm saying,
(27:36):
So it always flows in that direction that cannot reverse
with direct current. So the electro magnet inside this piston
generator thing was acting just like a stationary permanent magnet was.
In fact, Tesla could have just put a very powerful
permanent magnet in this thing. It would have worked the
same way when you move a conductor through a stationary
(27:59):
magnetic field. So like you have a conductive material and
you pass it through a magnetic field that induces electricity
to flow within the conductor. You induce electric current by
moving the conductor up and down past this electric magnetic field.
Rather then you know, having this oscillating or reciprocating action
(28:21):
as the the coil moves up and down through this
this magnetic field. You actually have a similar effect as
if the magnetic field was fluctuating, was reversing its current
back and forth. So it's it's almost the same as
if the the coil were stationary, but the electro magnet
around it was powered by alternating current. Now, the reason
(28:43):
why this is important is that that would actually reverse
the flow of electricity through that coil. You generate alternating
current by moving this this coil up and down through
this magnetic field. So you take a direct current source
from the battery into this reciprocating electric generator, and by
(29:04):
moving this piston up and down, you can output alternating current. UH.
To provide the up and down power to move the coil,
we have to go to the piston. Now, in this
early invention, the piston was driven by steam power. Now,
I wish I could adequately describe Tesla's design here because
(29:26):
it really was genius. I mean, it was a beautiful
approach to creating a piston that can move up and
down be driven by steam, and it was beautifully simple
uh in design. However, to describe it is really hard
to do without visual aids. There are videos that You
can watch that show how this worked, and I recommend
(29:48):
you check it out if you want. But what you
need to know is that Tesla's piston served also as
a valve, and that valve controlled where steam could enter
an exit the cylinder that the piston was moving in.
So Tesla was using steam for both directions of the
stroke of the piston. So the upward and the downward
(30:10):
movements of the piston were driven by steam. Steam would
push the piston down, steam would push the piston back up,
and this would drive that coil to move up and
down the magnetic field further up inside the electric generator,
and thus the piston was providing the reciprocating motion. Now
let's get to resonance. So the story Tesla told is
(30:33):
that he was working in the lab late one night
when his eyes beheld an eerie sight because his reciprocating
electric generator or some oscillator that was similar to it
because it changes from story to story, was moving at
the same frequency as his buildings natural frequency. Some versions
(30:54):
of the story say that he had attached the piston
to a girder to provide stability, because obviously, if you
have something that's moving up and down rapidly. It's going
to be clattering all over the place unless you has
strap it down somewhere. So he was saying that he
was tuning in the resonance or the frequency rather of
(31:14):
this oscillator, so it resonated with the girder that it
was connected to within his building, and thus he began
to introduce increasingly violent vibrations into the building, and those
vibrations continue to build an intensity, and it led to
a small man made earthquake, leading a lot of people
(31:34):
to call this Tesla's earthquake machine. Then the story goes
that police and ambulances responded to the scene and they
got there justice Tesla was either taking a sledgehammer to
his generator to stop it from tearing the joint apart,
or that he had already stopped it and that he
was just playing coy and saying, oh, I didn't even
(31:56):
notice an earthquake. Now, could such a thing be possible?
Maybe you could theoretically create a reciprocating device and tune
it to a frequency that induces vibrations in a structure,
And theoretically you could maybe do one powerful enough that
ultimately it would start to cause damage. But We need
(32:17):
to keep several things in mind here. One is that
Tesla mostly told this story in his declining years. Uh.
The account I see most frequently cited comes from an
article that was published in nineteen on Tesla's seventy ninth birthday,
(32:37):
and that the actual shaking of the building was said
to have happened either in eighty seven or eight eight eight,
according to that article. So even that article doesn't get
specific on when this supposedly happened, and a different source
targets the the event to eight, so we don't even
(33:00):
have agreement of when this supposed earthquake happened. Tesla also
told other stories at that same party that are referenced
in the article I was mentioning, like the fact that
he had discovered cosmic radiation before anyone else did, he
just didn't think to tell anyone about it, and that
he found there are particles that traveled perhaps as much
(33:21):
as five times faster than the speed of light, which
just isn't true. So my point is that Tesla is
at best and unreliable source when it comes to stories
about his own work. In many ways, his life depended
upon his fame at this stage in his life he
was drifting from hotel to hotel in an effort to
(33:43):
avoid homelessness, and hotels would be happy to receive the
famous Tesla at least initially, but eventually his welcome would
wear out and he'd take the show on the road again.
So I have my doubts about Tesla's stories. At least
I doubt he was producing enough vibration to simulate an earthquake.
And I definitely doubt the versions that suggests that not
(34:05):
only was this building shaking, but that glass was bursting
from nearby buildings and that the road outside was quaking.
I don't believe that for a second. And one reason
I doubt this is that you've got a lot of
material and buildings that can have a dampening effect on vibrations. Right.
Not everything is contributing to this resonant frequency, this resonant oscillation.
(34:29):
Some stuff ends up resisting that and inhibiting that. And typically,
or usually, like the larger the thing you're trying to
to to vibrate, the larger the thing you're trying to
shake apart, the more force you need to really get
things going. In other words, if you walk up to
(34:51):
a building and you happen to know exactly how frequently
you need to tap on a girder to match the
frequency of that girder, and you do it. Uh yeah,
you're tapping at it, and you could probably feel those
vibrations along the length of the girder, but you're not
gonna force it to break apart. You'd have to use
more force than that. Pushing a kid at just the
(35:13):
right moment in the swings arc gives the kid a
significant boost, but you do have to push. You can't
just you know, like tap, it's not gonna do anything.
So the source of the vibrations have to produce waves
of significant amplitude to affect something like a building. Same
thing with the wine glass. Right, If you can produce
the right note, but you're not producing it at a
(35:35):
high enough volume, the glass won't break. It will vibrate.
If you put something like a piece of paper inside
the glass, you'll see the paper jump around because the
glass will be vibrating, but it won't be enough to
cause the glass to deform to the point where it breaks.
So I just doubt that Tesla's oscillator would be able
(35:55):
to do it, particularly the way he was describing it.
In his later descriptions of the technology, he said that
he had as an air powered one that could fit
in your pocket. So it was like a smaller version
of the oscillating electric generator. So technically, yes, I think
(36:16):
you could do this if you had something that was
significantly powerful enough to introduce vibrations that would ultimately cause destruction.
I just don't think Tesla's did it. I don't think so,
but I could be wrong. It's it's the hard thing
is that there just aren't any reliable sources outside of Tesla,
(36:39):
and Tesla was not a reliable source. He made a
lot of claims that have been unsubstantiated, and many of
them I believe were really meant to help keep him
in the public eye so that he could, you know,
live out his life with as little hardship as he could. Again,
(37:01):
he lived rather tortured existence, So no hard feelings against
the guy. He was just trying to get through life
under frustrating, to say the least circumstances. I mean, I
could go into the whole story about Tesla and Marconi.
If you think Tesla and Edison is one of those
big tales of two people, you know, posed against each other,
(37:24):
which really I would say Edison Westinghouse really is that story.
That's nothing compared to Marconi and and Tesla in my mind.
But that's the story for another time. Anyway, hope you
enjoyed this discussion about resonant frequencies and how a Janet
Jackson music video was shutting down computers left and right
in two thousand five. I found it interesting. I hope
(37:46):
you did too. If you would like me to cover
something specific on tech stuff, please reach out to me.
One way to do that is to download the I
Heart Radio app. It's free to download. You can navigate
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(38:07):
H s W and I'll talk to you again really soon. Y.
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