Extreme Engineering to Create the World’s Stillest Rooms


[This episode is sponsored by Skillshare] [ INTRO] Sit still for a second. What do you hear? Maybe a siren across town? A jet overhead? But how about the really tiny noises? Your breath? Your heart? Your bones grinding against each other? These sounds are so quiet they’re barely
there. But for some experiments, even the softest
background noise is too much! So scientists have created rooms that are
unimaginably still. Take, for example, the room where LIGO conducted
the first experiment that detected gravitational waves—tiny perturbations in
spacetime—from two colliding black holes. It was an incredible triumph of science—but
also of engineering: the equipment had to sense tiny fluctuations
a mere fraction of the width of a proton in size! That meant eliminating every possible source
of movement. And they aren’t the only ones aiming for
perfect stillness. If your telescope is looking for planets hundreds
of light-years away, a little thermal expansion could mean the
galactic equivalent of photographing your thumb. And if you’re working at the other size
extreme, shooting electrons at individual molecules,
even the light tug of a fridge magnet could be disruptive. So scientists have resorted to extreme measures
to build the stillest rooms in the world. That means, first and foremost, eliminating
mechanical vibrations from things like trains, ocean waves, and
footsteps. The simplest solutions are passive—they
block vibrations just by sitting there. For example, springs can provide isolation—they
keep fast vibrations from being transmitted. Think of a car’s suspension on gravel: the
springs mostly absorb the tightly spaced bumps. Of course, fatter bumps, like speed bumps,
are too much for springs alone to hide. That’s why cars also have shock absorbers, which use friction to dissipate any bouncing
of the car body. That dissipation is called damping. Sensitive experiments need isolation and damping
too. Many labs use rubber pads or pneumatic table
legs, which provide both isolation and damping for sensitive equipment. If you’re building an entire vibration-free
room, though, you have more…hard-core options. The noise-free room in IBM’s nanotechnology
lab outside Zurich is built deep underground— right on the bedrock. That means any vibration is fighting the inertia
of millions of tons of rock. And it, as well as the stillest lab at The
National Institute of Standards and Technology in the US, also employs a more complex solution: active vibration control, where sensors detect
small motions and counteract them. It’s like noise-canceling headphones, but
for the ground. And speaking of noise, you might need to block
vibrations in the air, too—AKA sound. Obviously blocking sound is crucial for audio
measurements, like testing a model concert hall or checking
what background noises confuse Siri. But sounds also make equipment or samples
quiver, which can lead to problems like blurry images. To block outside noise, labs can be insulated
with layers of concrete and air. Microsoft’s underground audio lab, for example,
lives inside a six-layer concrete onion… And on top of vibration-damping springs, of
course. To stifle noises from inside a room, the walls and even the floor can be plastered with wedge-shaped
foam or fiberglass tiles. These break up and absorb sound waves, keeping
them from echoing off the walls. Hence the name for such rooms: anechoic chambers. Microsoft also paid special attention to little
details like how cables enter the room, how the doors are sealed, and how air is circulated. All that effort paid off: in 2015, Guinness certified the lab as the quietest
place in the world at negative 20 decibels. That’s barely louder than air molecules
bouncing around! Some experiments need to go beyond vibrations,
though: they need to control thermal expansions and contractions, too. Heat is especially important in experiments
like that LIGO one that use interferometry, where miniscule lengths can be measured by
looking at the effects of adding them to the paths of laser beams. LIGO kept the temperature constant for that
gravitational waves discovery by sucking out all the air in the room and
hanging instruments from insulating glass rods. That obviously won’t cut it when suffocatable
humans need access. In those settings, temperatures are normally
stabilized by air circulation. The problem, of course, is that air conditioning
is loud! And the moving air can directly vibrate equipment. That’s why that IBM nanotechnology lab uses
a gentle, upward-flowing ventilation system. The lab’s not quite as quiet as Microsoft’s, but it does manage to keep temperature fluctuations
to one hundredth of a degree Celsius! For experiments on the very smallest scales,
even electrical or magnetic fields can disrupt the stillness. Some modern microscopes sense tiny forces
between particles, and electronics manufacturers sometimes etch
circuit patterns using beams of electrons. Those critical particles can be deflected
by electromagnetic fields from any nearby source, including things like power lines. So to block those out, high-precision measurement
labs like the one at NIST wrap the whole room and sometimes the equipment
in magnetic metals. Just two layers can cut magnetic fields to
a third of the Earth’s normal field strength, and more layers push it down even further. It’s only by blocking mechanical, acoustic,
thermal, and electromagnetic noise that we can spy on distant black holes
or watch molecules flow into and out of a single neuron. Not all experiments need all these measures,
mind you, so different labs are quietest in different
ways. The IBM lab is unusual in trying to block
everything at once. If you’re seeking peace and quiet, though,
you might want to look elsewhere… these rooms are so silent many people can’t
stand more than a few minutes in them. Me, I’ll take some nice wind in the trees. I’ll leave the true silence to the microscopes. If you’re looking for a silent room to record
with microphones, this skillshare class on audio recording taught by young guru who is
a sound engineer for Beyonce, Jay-Z and many others Young Guru covers the scientific basics of
sound recording, how to set up a recording space, choose a microphone, and how to record
different kinds of vocals Right now SkillShare is offering Scishow viewers
2 months of free unlimited access to all of their classes. You can learn from Young Guru, a leader in
this competitive field for free. Check it out or any of the over 20,000 classes
by clicking on the link in the description and thanks. [ OUTRO]

100 thoughts on “Extreme Engineering to Create the World’s Stillest Rooms

  1. No, please. It causes no problem to stay in a very silent room, even for hours. This is a myth and it has been debunked many times already. (Cf Veritasium, but he hasn't been the only one to do the experiment).

  2. yeah like why don't we hear our mushed food disintegrating in our liver and passing through our intestines? or our strands of hair hitting against each other? or the sound of one hand clapping????

  3. Well done! Seriously.
    Much improved presentation.
    Good to see you again.
    Welcome back, Olivia!
    And best of luck the coming weeks.

  4. I recall John Cage doing musical experiments in an anechoic chamber. He said he could hear his blood flowing.
    I want to experience that for myself someday, it sounds really interesting.

    But I can also see why most folks can't handle that. It's simple: that kind of silence isn't natural, literally. It's alien to our brains and our instincts and therefore, it's disturbing.

  5. It's impossible to make a room totally free of vibrations on Earth, as the impact of Muscle Hank dropping his weights is felt through the whole world

  6. From Veritasium: "Can Silence Actually Drive You Crazy?"
    https://www.youtube.com/watch?v=mXVGIb3bzHI
    Actually, no

  7. Would it be offensive to notice the weight gain?… I mean… I'm still heavily attracted, but now I'm jealous of the father…

  8. I used to be a research assistant at an auditory perception lab at UC Berkeley and we had anechoic chamber. It was awesome! I wanted to bring in bean bag chairs and watch a movie with the rest of the people at the lab. When I first went inside, I could barely hear the lab manager who was just a few feet away from me.

  9. That is so cool! I simply cannot comprehend life without sound! It must be… I don't know! Maybe peacful, maybe weird!

  10. I'm sure 90% of YouTube education videos are sponsored by Skillshare now. And the other 10% are sponsored by Square Space.

  11. A car's shock absorbers work by squeezing air and damping it by oil squeezing through valves. Friction is avoided as much as possible.

  12. "sit still for a moment, what do you hear?"…. i didnt even get a chance to hear anything else than your voice…. VERY poorly used script for the video

  13. I'm not sure if it's still there, but there use to be an anechoic hallway at the Central Ohio Science museum in Columbus. Might be worth checking out if you are interested in audiology or physics

  14. 5:38 nope, I'm an extrovert, I don't need peace or quiet, I like to party, so I will disturb the silence in the room, and go straight up to partying.

  15. Actually… 😛 The reason why cars have dampers, is because without it you would get oscillations, even on an almost smooth road. Dampers dont actually reduce the movement very much. unless you are going faster than they can react/adapt. (and in the example you used the speedbump to symbolize it, and at very low(and too high) speeds, dampers hardly have an effect)
    P.s. I know I might not be as smart as you xD but I do have a mechanic education, which makes me feel confident enough to point out the potential misunderstanding.

  16. Just realised Olivia is now talking differently.

    Though I never hated how she talks, the way she talks feels like an improvement.

  17. -20 db? is that dB or dB or dB? I suspect you mean dB SPL. dB on its own is a ratio not a measure. In other words a dB measure is a measure of one thing with respect to another. Not only that, it can measure power (where 3 dB is twice the power of 0dB) or deflection like a voltage where (where 6 dB is twice the voltage), yes the two are the same, measured in different ways. 0dB on a "vu" meter is not anything to do with 0 dB SPL. 0 dB vu in the average theater is about 83 dB SPL, less in a living room. have fun.

  18. Sound & broadcast studios need anechoic walls, too; and one of the cheapest, and somewhat humorous solutions I've seen, was plastering all the walls with cardboard egg cartons!
    Crazy-looking, but it actually works pretty well!

    Fred

  19. I went into an anechoic chamber years ago as a grad student in music. The chamber was used to duplicate the acoustics of different concert halls with speakers embedded in the walls, but with the speakers off, it was so strange! My ears felt like they needed to pop, because that’s apparently what my brain associates with the sound dampening, and there was this strange hollow feeling in my chest from how the sounds of my pulse and breathing were effected. Hearing myself speak in the chamber was bizarre, too. I definitely wouldn’t have wanted to spend much time there because it was so disconcerting.

  20. I know you guys are big on editing out inter-sentence gaps, presumably for information density's sake, but maybe you could dial that back right after, "What do you hear?"

  21. We have an anechoic chamber where I work. When you're inside, you feel a pressure on your ears. I speculate that the pressure isn't real, but merely the sensation of having your eardrums not move, such as when you are in a high pressure environment prior to equilibrating the pressure in your head.

  22. Hey I never told you guys but, thanks for not putting ridiculously annoying music in the background. It serve no purpose indeed.

  23. When everything is silent and I take a test, my brain improvs one of the podcasts I listen to. I find this to be very comforting personally

  24. Is this entire video about the room where her love life went to die in silence because she’s so hipster no one gets her… or the failed attempt at hiding the underbite with the droopy eyes and croaky way she ends every sentence?

  25. I love this show!
    Constructive criticism: the host in this (and her other episodes) is talking way too slow, and is dragging the last syllable of every sentence for too long. It makes the audience tune out.
    Again, I love this show and all their hosts.

Leave a Reply

Your email address will not be published. Required fields are marked *