Sound can be various physical objects, which are in a solid, liquid or gaseous state.
For example, a vibrating string or blowing air from the pipe.
Sound is the wave of the environment,Perceived by the human ear. Sources of sounds are different physical bodies. The vibration of the source excites fluctuations in the environment, which propagate in space. Sound waves occupy a frequency range from 20 Hz to 20 kHz, between infrasound and ultrasound.
Mechanical vibrations arise only whereThere is an elastic medium, so in a vacuum, sound can not spread. The speed of sound is the speed of the passage of a sound wave along the matter surrounding the source of sound.
Through gaseous media, liquids and solidBody sound runs at different speeds. In water, the sound spreads faster than in the air. In solids, the speed of sound is higher than in liquids. For each substance the velocity of sound propagation is constant. Those. The speed of sound depends on the density and elasticity of the medium, and not on the frequency of the sound wave and its amplitude.
A sound wave can curve around thelet. This phenomenon is called diffraction. At low sounds diffraction is better than in high ones. Here the sound characteristic affects the direction of the wave movement, but not the speed.
Formula for calculating the speed of sound in any one-component medium:
C = 1 / ???, where
C is the speed of sound,
? - density of the medium,
? Adiabatic compressibility of the medium.
For a medium from a mixture of liquids or gases, the formula becomes more complicated. In practice, reference tables are used that contain the already calculated values of the speed of sound in various substances.
The state of the environment through which the soundWave, depends on numerous external factors: temperature, pressure, heat exchange between different objects. Therefore, reference tables containing data on the speed of sound in various media are necessarily provided with notes on the magnitude of external parameters.
The speed of sound in the ambient air is approximately 340 m / s, in water 1500 m / s, in steel - about 5000 m / s.