Introduction
Mechanical Wave
Sound is a mechanical wave. It has an original source that is a vibrating object. It travels in a medium through particle-to-particle interaction.
Longitudinal Wave
In a sound wave, the particles in the medium oscillate in a direction parallel to direction of energy transport. This results in compressions and rarefactions in the particles- Lower pressure causes molecules to expand into a large region of space called rarefactions, and higher pressure causes molecules to compress into a smaller space called compressions. In a longitudinal sound wave, wavelength is the distance that a disturbance travels along the medium in one complete wave cycle, therefore the distance from one compression to the next …show more content…
In sound waves, high frequency coordinates with high pitch, and low frequency coordinates with low pitch.
Wave Interference
Wave interference occurs when two waves meet while traveling along the same medium. There are two main types of wave interference. Constructive interference is when two waves of the same shape travelling in opposite directions meet up, causing the medium to displace twice the amplitude of the two pulses. [diagram] Destructive interference occurs when an upward and downward displaced pulse of the same shape traveling in opposite directions meet up, cancelling one another’s effect on medium displacement, so that the medium assumes equilibrium position. [diagram]
In longitudinal sound waves, wave interference is related to the wave’s compressions and rarefactions. Constructive interference in sound waves is when high-pressure compressions from two waves meet up and the net effect is an even greater pressure. The same applies with rarefactions, resulting in a lower pressure. If this is repeated, the two sound waves will continually reinforce each other making a very loud sound. These are called