| Added | Mon, 09/01/2017 |
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This version includes all known sounds that for some reason were mistaken for something paranormal.
This is a general version, where natural sounds of nature, animals, insects, birds (their characteristic sounds or imitation), as well as various mechanical sounds are collected.
In particular:
Thin ice on the surface of the water plays the role of a membrane. By throwing a stone at it, we generate vibrations of water under the ice in a wide frequency range. Vibrations at resonant frequencies fade out quite slowly, at the rest - very quickly. Some time after the stone is thrown, the water under the ice fluctuates with a certain frequency - the frequency of its own vibrations, which depends, among other things, on the depth. The water presses on the ice from below, and it makes sounds, playing the role of a speaker membrane. In addition, the ice layer spreads the disturbance from the stone throw at some distance around the epicenter. Thus, the ice fluctuates at different points on the surface, with different frequency (due to different depths) and amplitude (which decreases as you move away from the place where the stone hit). We get a large set of sources of sound vibrations. The sound at the receiving point (the place where the observer stands) is determined by the sum of these oscillations, and in general can have modulation in frequency and in level (beats).
It is also possible to distinguish a well-known sound characteristic of overcoming the sound barrier.
The sound barrier in aerodynamics is the name of a number of phenomena accompanying the movement of an aircraft (for example, a supersonic aircraft, rocket) at speeds close to or exceeding the speed of sound.
When a supersonic airflow flows around a solid body, a shock wave is formed on its leading edge (sometimes more than one, depending on the shape of the body). At the front of the shock wave (sometimes also called a shock wave), which has a very small thickness (fractions of a millimeter), cardinal changes in the properties of the flow occur almost abruptly — its velocity relative to the body decreases and becomes subsonic, the pressure in the flow and the temperature of the gas increase abruptly. Part of the kinetic energy of the flow is converted into the internal energy of the gas. All these changes are greater the higher the speed of the supersonic flow.
The first pilot to reach supersonic speed in controlled flight was an American test pilot Chuck Yeager on an experimental Bell X-1 aircraft (with a straight wing and an XLR-11 rocket engine), who reached a speed of M = 1.06 in a gentle dive. It happened on October 14, 1947.
Electromagnetic-induced acoustic noise or coil howl sounds different in Europe than in the USA. The American electric drone is B flat, whereas the European one is salt. Perhaps this is due to the fact that in Europe 220-240V voltage standards are used with an alternating current frequency of 50 Hz, and in the USA 100-127V and 60 Hz, respectively.
video from "Vkontakte" authored by Alexander Poteryakhin
Translated by «Yandex.Translator»
Sound wave. Illustration
Translated by «Yandex.Translator»
As breaks the sound barrier
The comment from the youtube page from the user Irenka:
Me here the brother is asked to translate, I think, maybe someone else would be interested. The translation is crude, but the meaning is clear good. Paragraphs is a change of personnel.
"Sound travels at about 760 miles per hour, or 340 meters per second. It is approximately 661 node in a normal day at sea level. And sometimes you can almost see it. Travel close to the speed of this, can cause some unusual visual effects.
You look at the NASA photo СР71 bending of a light wave by the pressure difference which it creates. Air pressure and temperature drops when the air velocity increases. Rapid changes in density can be enough to bend light like a lens. How does it happen?
The speed of air increases when it flows around the aircraft approaching the level of 1 (speed of sound). This means that although the aircraft is slower than the speed of sound, it can increase the speed of the air moving around it to speeds above the speed of sound.
When the pressure around the plane falls, the air cools and when it cools, its ability to retain moisture decreases. So, if there is enough moisture, then you will see it in the form of clouds, which seem to be attached to the tail of the aircraft. But the cone-shaped cloud you see, will not move with the plane.
Each part of the air spontaneously reacts to changes in temperature and pressure caused by the body of the aircraft moving through it.
There are also shock waves. These waves are generated by air that can't get out of the way of the plane fast enough, forming a pressure wave. We perceived this wave as a sound. In General, the plane usually creates two "explosion", but they reach us so quickly that we can't separate them.
All of these factors are quite normal and expected in the description of supersonic and transonic flight. But in rare cases it is possible to observe something special. At Kennedy space center on 11 February 2010 the Atlas rocket, which was launched in perfect conditions for demonstration of the shock wave showed that such a result."
Translated by «Yandex.Translator»
"Singing" cicadas
Video channel Meristogenys69
Comment to the video:
Cicada - Tacua speciosa advertisement. Peninsular Malaysia, 11th May 2014. Documented by Leong Tzi Ming.
Translated by «Yandex.Translator»
The three-whiskered bell-ringer, or the three-whiskered blacksmith (lat. Procnias tricarunculatus), is a migratory bird of Central America in the Cotingaceae family.
Three Wattled Bell Bird - Costa Rica
26 Sept. two thousand eight
Author: nickmcg8840
Singing train in the steppe
May 31, 2012
Author: periskopspb
The sound is caused by the vibration of the rails
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Вот похожий эффект, но только от поезда в степи
А вот похожий эффект, который возникает при катании на коньках по тонкому льду: