What is the nature of sound waves??
Hi,
Let us begin by the phenomenon with which sound waves reach us or we are able to hear ‘sound’
First of all a source producing sound should be there . It could be anything like a vibrating vocal chord of the person, or vibrating tuning fork etc.
These vibration disturbe the 1st particle of the medium. If it is air, then the first air molecule starts vibrating on receiving the wave, the energy is passed to the next molecule and so on.
Hence we see that a material medium is a pre requisite for sound waves to travel. See the figure below:
Here the tuning fork is producing vibrations which in turn vibrate the air particles.
A sound wave is described by 5 characteristics:
Amplitude
Amplitude of a wave is the maximum displacement of medium particles in either direction from their equilibrium (rest) position. SI unit of amplitude is ‘meters’.The loudness of a sound is directly related to its amplitude. A loud sound has larger amplitude as compared to a soft sound.
Loudness and Intensity
Intensity is amount of energy passed per unit area per unit time. Loudness is measure of response of a sound by the ear.
Wavelength (λ)
Distance between two consecutive compressions or rarefactions.
SI unit is meter.
Frequency
The number of cycles/vibrations produced by a source of sound per second is called frequency. It is the rate at which sound wave is produced by the source. SI unit is Hertz.
Quality of the sound
Quality is a characteristic of sound that enables us to distinguish between sounds having the same loudness and pitch. eg we are able to distinguish between sounds made by two men etc by quality of their sound.
Time period (T)
The time required to complete one full oscillation or cycle is called the time period. It is also defined as the time interval between two consecutive crests or troughs of a wave
It has SI unit of seconds.
speed
The distance travelled by a wave in a given interval of time is called its speed. Speed of sound wave is very less as compared to light waves. The SI unit of speed is m/s.
Along with these temperature, medium and nature of material are also characteristics of sound. For eg sound travels faster when temperature is increased.