الصوت .. الفيزياء

Sound .. Physics

Sound

Sound is known as a form of energy transmitted by waves. The source of sound is usually a vibrating body located within a gaseous, liquid or solid medium, whose oscillations and vibrations cause a similar movement in the molecules of the medium in which it is located, and then move from one molecule to another adjacent to it. It is loaded with energy that travels in all directions, and sound waves, unlike electromagnetic waves, need a medium in which to travel. Therefore, the process of sending sound in a vacuum, such as outer space, for example, is characterized as a kind of impossibility.

The sound wave in which the molecules move back and forth in a direction parallel to its direction. It is called a longitudinal wave. It is known that electromagnetic rays, such as light and ultraviolet rays, are transmitted by transverse waves. When the molecules move in the same direction as the sound wave, they crowd each other and thus increase their pressure value.

But if they move in the opposite direction, the result is a decrease in the pressure value. For this reason, we can consider the sound wave as a continuous change in the pressure of the medium in which it travels.

(The change that occurs in the pressure of a vibrating medium and in the positions of its molecules)

The human ear is characterized by being a very specialized organ whose function is to pick up sounds and send all auditory information about everything around us to the brain. It is capable of picking up any change in air pressure resulting from the passage of a sound through it, even if it is faint, and converting it, inside a thin skin membrane, which is the eardrum, into mechanical vibrations that are an exact copy of the vibrations emanating from the source of the sound itself. There is a series of tiny ossicles in the ear that connect the eardrum to another membrane that is much smaller than it. These ossicles are: the malleus, the incus, and the stirrup, and their function is to transmit sound vibrations to a fluid in the cochlea, which is a spiral-shaped organ with approximately two and a quarter turns, and converts mechanical vibrations into electrical impulses that are transmitted by the auditory nerve to the brain. In addition, inside the cochlea there are thousands of hairs with roots made of nerve cells that move whenever the fluid around them moves and transmit impulses to the brain. It is believed that the cochlea can distinguish between sound frequencies and inform the brain about the loudness of each frequency. Although the frequency range that the ear senses varies from person to person and decreases with age, the ear can generally distinguish within a range of 20 to 20,000 Hz (the auditory frequency range).