Meet Noisy.
The robot that… make noises.
Most people don’t appreciate his somewhat strange purpose, and find him irritating at
best.
But in all actuality, this little robot can provide a unique excursion into the world
of sounds, because his memory contains all the tones of the universe.
Today we’ll find out just what Noisy can do, and discover a lot of intriguing things
along the way.
It’s pretty easy to help him, all I need to do is set my imagination free and give
him a challenge!
Let’s try this.
Noisy, can you give us the quietest sound imaginable?
Hmm, it seems like nothing’s happening here.
We’re…..still waiting, Noisy.
Oh, I know what the problem is.
The loudness, or should I say quietness of this sound, is nearly immeasurable, because
what Noisy is broadcasting right now is the sound of air molecules moving around us.
And they move all the time, vibrating, and therefore technically making a sound.
This is why the superhuman characters in movies seemingly have so much trouble adapting to
their powers, like super hearing: they can hear the air itself, and anything else would
be too much noise to deal with!
Good thing we don’t have to worry about that, so let’s move on and come up with
another task for our little robot friend.
Noisy, can you make the sound of the quietest room in the world?
The sound here is around -20dB, which means that it’s 20dB below the hearing threshold
of our ears.
This room isn’t just quiet; it’s basically swallowing any sound it encounters.
This room is called the Microsoft chamber, and is found in Redmond, Washington.
It holds the Guinness World Record as the quietest place ever.
Wow, it seems like my own voice became a little muted here.
That’s happening because Noisy isn’t just playing recorded sounds – no memory can
contain this much information.
Instead, sounds are coded in his memory by their qualities, like intensity, pitch and
even the density of the space they’re spreading through.
Noisy is a one-of-a-kind robot that, using these qualities, can make the air itself move
as if a particular sound was manipulating it.
This gives us the unique opportunity to hear anything – from the depths of the ocean,
to the vacuum of space.
For example: Noisy, what would be the quietest sound that we could actually hear?
Sounds familiar.
This is the sound of you calmly breathing, and your heart beating.
At just 10 dB, we won’t ever notice it in our everyday life.
But remember that we’re still in the quietest room in the world, so you can hear it clearly.
Fun fact: we aren’t used to hearing our own heart and lungs.
Our mind perceives these sounds as a distress call, because if your heart beats loudly and
your breath is too heavy – this typically means that you’re in danger.
The brain will desperately scramble to figure out the reason for this reaction; which is
why no one, to this day, was able to be in the anechoic chamber for longer than 55 minutes.
It’s really uncomfortable!
Let’s move on to something more tangible.
To hear 60 dB I don’t even need Noisy.
This is about the volume of me talking to you right now.
Or anyone talking to anyone else, actually.
A change of 50 dB may seem drastic, but this level is a real comfort zone for our ears.
Turn the volume up another 50 dB, and you’ll run from the source of the noise as fast as
you can!
Am I right, Noisy?
He knows all about it.
And here, something strange happens.
Noisy, give us the sound of traffic, please.
It’s just 10 dB louder than a normal conversation, but I swear it sounds like something ten times
louder than that!
This is because our ears aren’t precise instruments of sound perception.
In reality, they’re constantly working in tandem with our brains, forming a way to adapt
sounds to be convenient for our hearing.
As I already said, the key definition of a sound’s loudness is in its pitch and intensity.
We’re naturally programmed to hear high pitched sounds as if they were louder than
others.
And anyone who has an annoying alarm waking them up in the morning can tell you that!
This a natural adaptation that makes it easier for us to react to the high-pitched sound
of a baby crying; it’s an uncontrollable reaction of our mind to find the source of
the high pitched sound, like the baby, and make sure that it’s not a distress call.
We also don’t perceive intensity as it actually is.
If you raise the intensity of any sound, it won’t make any difference to your ear until
a certain point.
It’s easy to represent this way: Noisy, please give us the traffic noise once again.
Now make it sound like 10 different streets with traffic around us.
Yeah, that’s enough, Noisy, thank you.
The sound just doubled its volume.
It’s called the rule of thumb for loudness: If the source of the sound is multiplied by
10, it’ll sound only twice as loud to our ears.
They don’t detect minor changes in volume; this is the reason why it’s easier for us
to measure sound in decibels, which is the same as 10 bels.
A change from 60 dB to 61dB just won’t make any difference to us at all.
Noisy, do you know any piano melodies?
Yeah, perfect!
And now, show us how loud a roaring truck is.
Thank you!
Both things you’ve just heard are normally around 80dB.
They have the same level of loudness, but one is pleasant to us and another is barely
tolerable!
This is another quirk of our hearing that proves that we don’t just have a couple
of microphones in our head, but a complex system that can adjust the loudness of any
sound depending on how we perceive it.
But here comes the point where another fluke happens in our perception.
At 100 dB, the intensity won’t matter, whether it’s a trombone, an elephant trumpeting,
or a helicopter –they’d all sound equally loud because we’re getting closer to our
limit.
Noisy, don’t take it personally, but can you present all the following sounds to us
from inside this semi-soundproof chamber?
The safety limit of our ears is situated at around 120 dB.
Any sound beyond that would be painful to hear at a close distance.
These are sounds like the cymbal crash in a band, a police siren, or a jet plane taking
off from the ground.
But there are a lot of sounds that lie in that dangerous territory that we can explore.
For example, in the animal world, there’s no species louder than a sperm whale.
This majestic creature can produce a series of sounds at the astonishing level of 230
dB.
No human being could bear this much noise – it’s far beyond our reach of perception.
This sound can travel for 10 miles underwater, and it’d be a good idea to stay out of its
range.
Another underwater animal that can literally stun with the sound it makes is the tiger-pistol-shrimp.
Yep, from one of the biggest animals in the history of our planet to one of the smallest.
But it isn’t called pistol-shrimp for nothing.
In fact, it’s louder than its namesake.
This shrimp can clap his claw and shoot a stream of water so powerful that it creates
a bubble with a high force, which, when it pops at 200 dB, will stun every fish within
a 6.5ft radius.
And then they’ll probably get eaten for lunch.
The loudest sound ever registered on our planet was the sound of the Krakatoa volcano eruption
in 1883.
The sound waves from this explosive event went around the whole Earth 4 times, and were
clearly audible 3,000 miles away from the volcano itself.
Even Noisy gets a little scared when we’re getting to this part of the excursion.
Still, there are even greater powers in our universe than this one.
There was a sound detected that’s as powerful as 100 million supernova explosions.
And don’t even try to ask Noisy to make this noise out loud.
He can, but he won’t, because he doesn’t want our planet to explode.
Normally it’s quite hard to tell how loud objects in space are, because in the vacuum
of cosmos, there might only be very thin gas that can’t transfer soundwaves.
Except when we’re talking about a black hole in the Perseus galaxy cluster.
This monster can produce a sound that would cover thousands of light-years around it,
even if there’s little to no gas in this space.
Even a brave little robot like Noisy is scared of this one!
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