Como ouvir com os olhos (EXPERIÊNCIA do PRATO DE CHLADNI)

Everyone knows that we perceive sound by the ear. right? !

duurrr Well, kind of. Because today, I'll show you how you can listen with your eyes and instead of listening, you will see the sound You may already know that Blizzard the company that made World of Warcraft, Heartstone, Diablo it's launching a new game called Overwatch The game's story it happens in the future No There is a future full of disaster, like a zombie apocalypse. But it has several weird forces and threatens a peace that was achieved with great difficulty and it is in this environment full of hope where a group of heroes must fight to maintain order in the world and put things in balance again.

And then Blizzard hired us, to do some experience that has to do with Overwatch, using some game technology of or that has to do with some character. And we found a character who not only has everything to do with the world's Manual. but it has everything to do with us Is the Lucio!

The guy is a DJ of Rio de Janeiro And all the powers his has do with sound. He It has a sonic amplifier which sends sound projectiles and can even send enemies back with the sound explosion. Lúciu also creates sound shields and even energizes people with music this makes them become faster, or recover life.

But it sound have that much power? Us we can for example move things with the sound? The What is sound, after all?

To understand all this we will do an experiment called Chladni plate It's a very cool way in to see the sound and at the same time see the effect of sound on solid things I am goin to use basically A amplifier a speaker and a tablet the sound will be generated in the tablet It will pass by the amplifier will send for speaker and here on the speaker, I go install a small plaque first I'll adapt my speaker to install the card I go take that front part and put a tube for PVC On the free part of the speaker. That part that moves And at the end of the PVC pipe I'll install a screw, this screw will stuck in my plastic plate. To finish, I'll weld a sound cable here in speaker and to connect the other end of the amplifier And I will go also put a cord coming out of my tablet and connecting the audio input of the amplifier Installation is basically this and the what I will touch in this, speaker?

I installed the tablet one sound generator, sound generator is like a keyboard (instrument) with the difference that the keyboard you can play only those notes that are in each key there In tone generator not, if I want a note for example that stands between a key and another I can generate this note So come on I'll put here 440Hz which is the equivalent to the note on the keyboard Just take a peek at what will happen to this board that is up here Unless You have superhero eyes, you can not see anything here. Only gave to hear the sound looks just now This crowd here is sound, your eyes are seeing sound, but if you think the sound just have this formart is not well like this no. Look What happens when I change the note, when I change the frequency of the sound This plastic board works very well with the lower frequencies We will swap for this one metal that will work better with higher frequencies Beauty, bora then understand why I'm not kidding you, you actually saw the sound here First thing we understand o'que is sound, sound is the vibration of the things we can perceive with our ears, if I hit such a wrench a mouth in a sledgehammer The blow makes the hammer is the mouth wrench, vibrate, this vibration passes through the air and our ear perceives this vibration, then our hearing is nothing more than a vibration sensor And the faster these more vibrations will be the sound, there at the beginning I gave example of the note A 440 Hz, the 440Hz is a standard for tuning musical instruments 440 Hz means 440 vibrations per second If I play the note Sí coming soon after are then 494Hz, or more vibrations per second and if we just find that sound is vibration, can you imagine that yes, you can create a sound weapon that neither Lucius uses there in the Overwatch you can have for example a weapon it hurts the ear of the people, because our sensor has a limit It works like a speaker if you turn on the last volume, he it will vibrate too much and it spoils and it can happen to our ears, so I used ear plugs during the experience You can also have weapons that do not hurt exactly heard but the sound too loud may give you a headache, dizziness can give then there is even sound cannon that police in some countries use to disperse protest and manifestation Another way to create a powerful sound weapon, would to be air vibrate suddenly and a very strong way creating a tsunami kind of sound This phenomenon exists and has the shock wave name It is what happens when a airplane gets too close to the speed of sound, or pass the speed of sound And it happened in Brazil in 2012 when was having a presentation in Brasilia an Air Force fighter has swooped on the building of the Supreme Court caused a shock wave and broke a lot of glass building And it is this idea that there is the sound blast that Lucius use to ward off enemies in Overwatch But beauty, gave to understand what is sound and that gives to create sound gun and what it has to do with this experiment?

What is there is that we have the impression that only the sound propagates through the air, but the sound also goes by the liquid and the solid By the way the sound moves much faster at the net and even faster by solid In detail is that sound travels in a special way, he walks in waves As like this walk the waves? ! It works something like this dish full of water here when you throw e stone makes the water vibrate and this vibration spreads in ripples; the sound is pretty much the same But these waves vibrate in a special way, I'll show it using a rope Look, I make a wave, can you do but I think we will do two waves Beauty ?

! I will try to do three Three Waves If this one were a sound, it would be here a sharp sound This here would be a more serious sound This here would be a more serious sound even But let's imagine now that this one is the dish that was vibrating upstairs speaker If I have a sound like the first note, the dish will vibrate whole but if I vibrate the second note you can see that there is a point where the rope is stopped Physically we call this point node and look, when I vibro the third string there are two fixed points, two nodes If I threw sand on top of that sand would shake where the whole string're vibrating and would build, stay where are we So this is what happens with this plate The speaker emits a sound that passes for plate, the plate vibrates But depending on the sound we create some regions that stand still and sand accumulates there And the more acute is the shortest sound will be the wave, and I'll have a much more detailed drawing, much more we And it is because of this that we can see the sound just looking at the design so that people on the board can see if the sound is more serious or if it is more acute And after knowing all this also gives you imagine how much the people who created the Overwatch had to study to build a character like Lúcio If you want to know more about this game, who the other characters, such as playing, which gives to buy, I am leaving the link down here The Overwatch's already available for PlayStation 4, PC and for Xbox One More videos that show you that fiction is not so far from reality as this video here you watch on here the World's Manual If you like music or like to tinker with sound we already made several videos here in the World Handbook exploring the science of these things, one of my favorites is one in which I take a can has a mirror in front and a laser pointed to that mirror And as we sing in the can, the laser projects a different thing on the wall, then you will singing and the design is changing as the note you're singing Another very cool video is when we filmed the sound in slow motion, the sound film! You can not say much that's it but we can see the speaker in slow motion, you can see a battery plate in slow motion If this board that we did here already have a very nice movement imagines a battery plate slowly.