2016 May

How Sound Travels

May 14, 2016

How Sound Travels

Sound is a movement of rarefaction and pressure waves that can travel for prolonged distances. It’s produced by the particles’ vibration in a given medium; a medium can be defined as the material through which the sound travels. A medium must be present sound waves to propagate. There is a variety of types of media through which sound waves can propagate, like, liquids, plasma, solids, gases, and so forth. Sound can’t travel via a vacuum.

Sound Waves Characteristics

The physical characteristics and speed of sound varies largely with change in its surrounding conditions. The speed of sound is depended on the density of the material through which it’s traveling. When the density is fairly high, sound travels at a higher speed. In gaseous media, the speed of sound varies with temperature changes. These are concepts frequently tested during Cambridge examinations and are taught during our Physics tuition class.

Sound waves frequency is simply the total number of pulsations produced in one second. The sound wavelength varies with respect to its frequency. When the wavelength is long the frequency is low, and when the wavelength is shorter the frequency is higher. Human ears are able to hear the sound waves lying between twenty and 20,000 Hertz (vibrations per second).

How Sound Waves Travel: For sound to be transmitted, three things are needed. These include; a source for sound production, a medium for sound conveying like, air, water, and so forth, and the receiver for sound detection.

Sound Creation

When an object moves through air, it brings about vibrations which in turn leads to compression waves formation in the air. Sound results from the propagation of these waves. For example, when the strings of a guitar are strum or a drum is hit, the to-and-fro movement of the drum head or the strings generates compression sound waves in the air surrounding it. Similarly, when speaking, the vocal cords vibrate and hence sound is produced. This type of vibration takes place not only in the atmospheric air, but also in other media like, liquids and solids. For example, a train moving on the steel rail, the produced sound waves travel by means of these tracks.

At ambient temperature, sound travels with a speed of 343 m/s in air, in water it travels at a speed of 1,482 m/s, and in steel at 5,960 m/s. This shows that, sound travels slower in a gaseous medium, which is because of its loosely bound molecules which have to travel a longer distance in order to collide with other molecules. In solids, vibration is freely transmitted since atoms are closely packed, hence sound travels faster. In liquids, the bonding between molecules is not as strong as in solids. As a result, the sound travels slower in liquids compared solids.

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