The Infrasound

The most interesting & funny but powerful concept is Infrasound. The infrasound is the sound which cannot be heard by human ears. The AF range is 20Hz to 20KHz. Below 16 to 17 Hz human ears cannot hear the sound which is infrasound. The range of infrasound is from .001Hz to 16to17 Hz.
The first naturally infrasound occuring infrasound was observed at time of krakatoa eruption in 1883,when concussive acoustic waves circled the globe seven times or more and were recorded on barometers worldwide. The infrasound was also used in world warII to locate artillary.
The infrasound is is very interesting & dangerous too. The infrasound is heard by various animals like tiger, elephants, hippopotamuses, rhinoceros, giraffes, okapi & some aquatic species like whales. The infrasound can make man feel awful, anxious, nervous. Infrasound can collapse your houses, buildings.
The ability of animals to sense the natural disaster in advance is due to their ability to sense infrasound. Infrasound sometimes results naturally from ocean waves, avalanches, earthquakes, volcanoes, and meteors. The animals can sense & respond to infrasound. They communicate between them with infrasound. The various experiments are going on to get effects of infrasound. When a animal like tiger or lion roar they have ability to make infrasound which scares thier prey.
Research by the late Vic Tandy, a lecturer at Coventry University, suggested that the frequency 19 hertz was responsible for many ghost sightings. He was working late one night alone in a supposedly haunted laboratory at Warwick, when he felt very anxious, and could detect a grey blob out of the corner of his eye. When he turned to face it, there was nothing.The following day, he was working on his fencing foil, with the handle held in a vice. Although there was nothing touching it, it started to vibrate wildly. Further investigation led him to discover that the extraction fan was emitting a frequency of 18.98 Hz, very close to the resonant frequency of the eye (given as 18 Hz in NASA Technical Report 19770013810). This was why he saw a ghostly figure — it was an optical illusion caused by his eyeballs resonating. The room was exactly half a wavelength in length, and the desk was in the centre, thus causing a standing wave which was detected by the foil.
The cause of humans fear at ghostly places is effect of infrasound. The infrasound affect human body very severely. The continuous bombarding of infrasound towards human can make heart beat faster, mild nausea, giddiness, skin flushing, and body tingling. As its power increases it becomes more & more destructive. infrasound at 110 - 130 dB would cause intestinal pain and severe nausea. Walt Disney and his artists accidentally experienced infrasound on one occasion. A cartoon sound effect was slowed from 60 cycles per second to 12 cycles per second via a tape-editing machine and was amplified through the theater system. The resulting tone, though brief in duration, produced in the entire crowd nausea that lingered for several days. So this sounds can be used in weapons. These weapons can takeover its targets without any severe damages.