Sound propagation


In order to clearly understand how different sounds are produced and how they can spread, it is important to first understand what sound is. The sound is a sensation produced in the ear by means of different movements vibratory s producing bodies. In other words, it is a set of waves that can be diffused through different means. The sound propagates from one place to another but to do so, you need a material medium .


What is sound propagation?

The propagation of sound is the way in which this, being a type of vibration , can be transferred from one place to another using different media which can be solid, liquid or gaseous.

  • features
  • Sound propagation media
  • Sound propagation speed
  • Sound propagation in solids
  • Sound propagation in a vacuum
  • Phenomena that affect the propagation of sound
  • Importance
  • Examples


Among the main characteristics of the propagation of sound we can mention that it has the ability to propagate by means of longitudinal and transverse waves . It needs a body that has the ability to vibrate in order to be transmitted as well as a medium, which can be elastic, liquid, solid or gaseous. An interesting quality is that it cannot be transmitted in a vacuum . It has an audible range of between 16 Hz and 20,000 Hz .


It has speed which is defined as the ability of the wave to go fast and pass through a medium or matter. The propagation of the wave has length , amplitude that describes the size of the wave, a period of time that is necessary for a complete wave to be produced, frequency or number of complete waves that are produced in one second and wave speed which refers to the distance the wave can travel in one second.

Sound propagation media

Before mentioning the means of sound propagation, it is important to understand that in this case, when talking about a medium, it refers to the group of oscillators that have the ability to enter a state of vibration thanks to the action produced by a certain force . The common medium by which sound can spread is air when it comes primarily to communication and acoustic systems between humans, also in speech or music .

So that the propagation of sound can take place, sound waves are needed which must fulfill three important aspects: be elastic , have mass and have inertia . In addition, the propagation of sound through a medium is linear , this means that the waves do not affect each other, it is a non-dispersive medium since all waves move with an independent speed and it is also a homogeneous medium , so sound can propagate in various directions causing what is known as a sound field.

Sound propagation speed

The speed of propagation with which a sound can be transmitted will depend on the sound source and the medium through which it is propagated. The solids have the ability to transmit sound more quickly and gases are much slower. The approximate speed of sound propagation in air is considered to be 340 m / s and in liquid media such as water it is 1500 m / s .

It is important to mention that the speed can vary when there are changes in the temperature of the medium through which it is transmitted, this because when the temperature increases, the frequency with which the particles in charge of carrying the vibration also increases. The elasticity of the medium also affects speed.

Sound propagation in solids

The best medium for the propagation of sounds is the solid state of matter. This is because in this type of body, the speed of the waves is determined by the relationship that exists between the elastic properties of the propagation medium and the volume . Solid media has a greater ability to avoid deformation, for this reason, waves can pass more easily and quickly because these materials do not suffer from deformations.

Sound propagation in a vacuum

Sounds do not have the ability to be propagated in a vacuum because there is no physical medium, so the mechanical wave of sound cannot move. In this way, in a vacuum you cannot hear sounds, only electromagnetic waves can be propagated, which do not need any type of medium to be able to move.

Phenomena that affect the propagation of sound

There are several types of phenomena that can affect the propagation of sounds, these are the following:

  • Absorption : it happens when a material has the ability to absorb sound waves.
  • Reflection : this phenomenon is known as echo and is produced when the sound is reflected in a dense medium, which causes it to reach the ear of the listener with a difference in time.
  • Transmission : depending on the elasticity of the medium, the sound will be able to propagate more easily.
  • Refraction : this phenomenon occurs when sound propagates and changes from one medium to another which causes its speed to change.
  • Dispersion : occurs when sound encounters an obstacle in its path of propagation.
  • Diffusion : this occurs when the surface where the reflection is produced has the characteristic of being rough, this causes the wave to decompose into several waves at the same time.


The propagation of sound is important because it is the way in which humans and animals can receive sounds from the external environment to be able to carry out different daily activities necessary, in many cases, to be able to maintain life and to communicate . The propagation of sound is also necessary in many of the branches that are related to science and physics .


Some examples of sound propagation are mentioned below:

  • When a church bell is moved to produce sound, it travels through the air, making it possible for people near the place to hear the sounds.
  • When a glass glass is struck with an object, it has the ability to produce sound waves, the closer a person is to the glass, the greater the ability to hear the sound.
  • In the mountains, being open spaces, sound can be transmitted easily and in many places it will have a tendency to cause the presence of echoes .

Leave a Comment