Sound waves

Sound waves are a type of wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.

Overview

Sound waves are created by the vibration of an object, which causes the air surrounding it to vibrate. The vibrating air then causes the human eardrum to vibrate, which the brain interprets as sound. In terms of the physics of sound, sound waves are typically described as longitudinal waves that require a medium through which to travel.

Properties of Sound Waves

Sound waves have several characteristics that allow us to perceive and interpret them as sound. These include frequency, wavelength, amplitude, and speed.

Frequency

The frequency of a sound wave is the number of vibrations that occur per second. The unit of frequency is the hertz (Hz). The frequency of a sound wave determines its pitch. High frequency sounds are perceived as high pitched, while low frequency sounds are perceived as low pitched.

Wavelength

The wavelength of a sound wave is the distance between two consecutive compressions or rarefactions. Wavelength is inversely proportional to frequency. This means that as frequency increases, wavelength decreases, and vice versa.

Amplitude

The amplitude of a sound wave determines its volume. A larger amplitude means a louder sound, while a smaller amplitude means a quieter sound.

Speed

The speed of sound is the distance travelled per unit time by a sound wave. It varies depending on the medium through which the sound wave is travelling. In general, sound travels faster in solids than in liquids, and faster in liquids than in gases.

Sound Perception

The human ear is capable of detecting sound waves with frequencies ranging from about 20 Hz to 20,000 Hz. Sounds with frequencies below 20 Hz are known as infrasound, while those with frequencies above 20,000 Hz are known as ultrasound.

See Also

• Acoustics
• Echo
• Noise
• Resonance
• Ultrasound