Sound is a wave that travels from one area to another. The wave itself is an oscillation of pressure that is transmitted through a gas, solid or liquid and is composed of various frequencies within the total range of hearing. The vibrations caused by the oscillation stimulates vibrations in the requisite sensory organs (ears) and is interpreted by our brain as a particular sound.

Sound energy is either the ability to utilize the ambient energy present in sound and converting it to conventional usage or the brute force that is produced from these vibrations, though it is generally seen as being not a suitable energy source from which to produce electrical power or any other form of power for human energy requirements due to the fact that we cannot gain a sufficient amount of energy from sound to be useful to this end at this time.

Sound is not measured in normal energy units such as Joules. Rather, it is measured in as pressure and intensity using such units of measurement as decibels and pascals. Such measurements of sound energy are typically related to other sounds that cause more or less pressure, and the pressure and intensity sound energy causes are combined into the common human term of “loudness” through which we experience sound, and will experience physical pain even if the intensity and pressure are great enough.

The human ear is usually capable of detecting frequencies between around 20 and 20,000 Hertz, although the upper limit in this range tends to decrease with advancing age and in any case is not precisely fixed. Different species have different ranges of hearing – dogs, for instance, can sense vibrations higher than 20,000 Hertz. Many species also possess special organs to produce sounds at special frequencies in order to aid communication and evade danger. In the wider, natural world such phenomena as lightning, earthquakes and rain are characterized by and produce their own unique sounds as well from the particular osculations they produce in either solid matter or even simply air pressure.

The mechanical vibrations that we and other animals can detect as sound are capable of traveling through any type and form of matter, be it gas, solid or liquid. The sounds itself is transmitted through these mediums as longitudinal waves, or compression waves. The sound waves periodically displace matter in the mediums they travel through and this displacement causes the matter to oscillate, thereby creating sound. Sound waves are principally characterized by frequency, amplitude, wavelength, speed, intensity and period and the characteristics of the sound itself can depend on factors such as the types of sound waves, whether transverse or longitudinal, along with the actual physical properties of whatever medium transmits the sound waves.

The speed at which sound energy travels is dependent on the properties and characteristics of the medium through which the sound waves pass, and in general terms the speed is proportional to the square root of the ratio of the mediums’ stiffness to its density. The physical properties, along with the actual speed of sound itself, will also be altered by ambient conditions — for instance in gases the speed of sound is dependent upon temperature.

(Energy FAQ Series)