Infrasonic and Ultrasonic Sound

"Nowacki, et al.’s 2008 study defines infrasonic noise as those frequency components of infrasound (1 to 20 Hz), plus low audible noise components up to 50 Hz. The audibility of infrasound depends on its acoustic pressure level. Thus, exposure to infrasound of a level below 120 dB does not cause unpleasant sensations and is harmless, whereas exposure to infrasound at 120 to 140 dB can cause slight disruptions of physiological functions and feelings of excessive tiredness. However, infrasound of 140 to 160 dB for a short, two-minute exposure can cause unpleasant physiological sensations such as balance disruptions or vomiting."

However, low frequencies below 40Hz can still have an effect on our ears, by causing balance disruptions through our semicircular canals and otolith systems, which are primarily associated with balance (Persinger, 2014; and Evans, Margaret J., and W. Tempest, 1972

Infrasound can propagate for millions of metres and can come from natural, artificial, and even

unknown sources (Persinger, 2014). Natural sources of infrasound include volcanoes, thunder, strong winds, earthquakes (seismic waves) or microseisms, big waterfalls, microbaroms, and geomagnetic activity (Persinger, 2014 & Nowacki, et al., 2008)

- there are also sounds that depending on your age are in your hearing range (one really high piched sound is called the mosquito sound)

here a link to try whether you can still here it: https://www.audiocheck.net/audiotests_mosquito.php

Research: Week 22 and 23

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