Pyracoustics

Here is another post with video that shows how sound makes the particles move

Pretty Sound

After seeing this video last week, it is definitely on my list of things to do this year! I’m currently unsure on my exact design, or whether I will create a Ruben’s tube instead, but nonetheless it is still a really cool idea (and probably the most interesting visualisation of acoustics)!

One of my current ideas is to create a few smaller Ruben’s tubes of varying lengths, each driven by a driver playing the same source. Because of their different lengths, they will resonate at different frequencies, each causing a different pattern of flames as the same source is played. If these were placed together (maybe in a stacked pyramid style) as music is played they would make a really cool music visualisation.

What do you think of the pyro board, have you seen anything like it before? If so, let me know or also if you have…

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What Sound can do.

As everybody knows, sound is energy, transmitted by vibrating particles. The closer the particles are located to more fast the sound will travel in the medium. For example speed of sound in air is 343 m/s, water – 1497 m/s and steel – 6100 m/s. This is a lot of difference. Although in dense, hard materials sound travels fast, it can not travel in vacuum, like space, so if there is no medium, sound can not be transmitted.

Sound does not simply travel fast but might brake a glass if loud it is loud enough. If you take a crystal glass and hit it with a finger to hear its resonant frequency, you can brake it just by directing loud enough sound waves through the glass with the same frequency. The glass will start to resonates and eventually will shatter. You can observe this in the video below.

Acoustic levitation is another event that happens by the use of sound. Scientists can levitate small objects in laboratory conditions. Creating a standing wave in a box, using two or more speakers to alter the sound frequency in the enclosure. As I mentioned before sound makes particles in a medium to move, when a standing wave is formatted it can trap small and light enough objects and make them stay still in the air, seeming they levitate. Here is a video of sound levitation. This device can more objects in a 3D dimension because it is using 4 speaker and creating 3D standing wave.

Same operation can be done with liquids. This allows mixing or separating liquids.

 

What is sound?

People use sound all the time. We rely on sounds to communicate. Unexpected noises may warn us of danger. The sounds we hear tell us a lot about our surroundings. Many animals also use sound. This is especially true of animals that live in water. Since only the very top of the ocean receives light from the sun, animals have difficulty using their eyes to find their way around in deeper waters. Once animals dive, they rely heavily on their hearing to sense their environment. In other words – vibrations that travel through the air, water, or another medium and can be heard when they reach a person’s or animal’s ear.

Sound is emitted from a speaker, the little black dots represent the medium moving due to sound pressure - the more dense the dots - the more pressure

Sound is emitted from a speaker, the little black dots represent the medium moving due to sound pressure – the more dense the dots – the more pressure in particular region.

Thanks to the ears – our hearing apparatus, we can perceive sound. Sound is a mechanical wave that results from the back and forth vibration of the particles of the medium through which the sound wave is moving. The motion of the particles is parallel to the direction of the energy transport. Since sound needs medium to travel, we can not hear sound in space. Human ear is capable of hearing sound withing a frequency range of 20Hz to 20kHz. Although we can not hear sound outside does not means that it does not exist, many other creatures have been adapted to hear the sound with lower and higher frequencies than we do.

References:

http://www.physicsclassroom.com/class/sound/u11l1c.cfm