Ten interesting facts about hearing

Dolphins with brain volume, approximately equal to the human, to those departments that are responsible for auditory function, we have ten times more space than that of Homo sapiens.



1. In the inner ear of about 25 000 cells reacting to sound. The frequency range of perceived hearing, is between 16 and 20,000 hertz. With age, he is reduced, especially by reducing the sensitivity to high-pitched sounds. For 35 years the upper limit of hearing falls to 15,000 hertz.

2. The ear is most sensitive to a range of 2000-2300 hertz. Best same musical ear (the ability to distinguish the height) are in the region of 80-600 Hz. Here, our ear is able to distinguish, for example, two sounds at a frequency of 100 hertz and 100 hertz 1. Number of people distinguish between 3-4 thousand sounds of different heights.

3. We are aware of the sound through the 35-175 milliseconds after he reached the ear. More 180- 500 milliseconds is required on the ear to "tune in" to the reception of sound, that is, to achieve the best sensitivity.



4. Elephant can hear infrasound frequency of 1 Hz (at least for a man - 20 Hz). Elephants use low-frequency sounds to communicate with the tribe. However, the elephants are able to hear not only the ears, and legs. So, they can feel the movement of the other herds of elephants, located a few tens of kilometers, as well as hearing and avoid distant combat zones.



5. Crickets and grasshoppers listen forepaws. They are covered with hairs, which is sensitive to the sound of the membrane. Dutch physicists were able to play the organ of hearing, which was one of the most sensitive acoustic instruments.



6. Fish catch fluctuations of water lateral line consisting of thin tubes sensitive.



7. auricle cat adjusts to the sound source reflexively. Leathery folds on cat ears are the resonators, and the number of nerve endings in the auditory organs twice the number in humans.



8. eardrum frogs is outside the body, behind the eyes.



9. Every tenth person in the world suffers from hearing loss and is testimony to the use of a hearing aid. However, four out of five people who really need hearing aids do not use them.



10. Deaf was not only Beethoven. Hearing loss guitarist «Dire Straits» John Ilsley exceeds 30%, which is a clear indication to wearing hearing aids. Twins from the group «Tokio Hotel» Bill and Tom Kaulitz hard of hearing since birth, and their hearing is continuously deteriorating.