Sound Waves and Their Properties

A disturbance that travels through a medium, transferring energy and momentum without transferring matter.

A wave that requires a material medium (like air, water, or a solid) to propagate.

The maximum displacement of a particle from its rest position as a wave passes through.

The distance between two successive points in a wave that are in the same phase of vibration.

The time taken for one complete vibration of a particle in the medium.

A wave that does not require a material medium to propagate (e.g., light waves).

The back-and-forth motion of particles in a medium as a wave passes through.

The quality of sound that allows us to distinguish between high-pitched and low-pitched sounds. It depends on the frequency of vibration.

The change in frequency of a wave as the source and observer move relative to each other. It's a result of the compression or stretching of the wavefronts.

The speed of the source relative to the medium (air in this case). It's usually denoted by 'vs'.

The speed of the listener relative to the medium (air). It's usually denoted by 'vL'.

The frequency of sound waves emitted by the source. It's usually denoted by 'n0'.

The frequency of sound waves detected by the listener. It's usually denoted by 'n'.

Loudness expressed in decibels (db) is 10 times the loudness expressed in bels (bel).

The formula for calculating sound intensity level (Ldb) in decibels is: Ldb = 10 * log10(I/I0), where I is the sound intensity and I0 is the reference intensity.

The threshold of hearing corresponds to a sound intensity level of 0 dB.

A sound intensity level of 10 dB corresponds to a sound intensity 10 times greater than the threshold of hearing.

A sound intensity level of 20 dB corresponds to a sound intensity 100 times greater than the threshold of hearing.

A 160 dB sound can cause immediate ear damage.

The decibel scale is logarithmic, meaning that a small increase in decibels corresponds to a large increase in sound intensity.

The time taken for a sound to decay to one-millionth of its original intensity after the sound source is stopped. This is caused by multiple reflections within a closed space.

The persistence of sound after the source has stopped, as a result of repeated reflections from walls, ceilings, and other surfaces.

A sound reflected back to the listener with sufficient intensity and delay to be perceived as a separate sound.

The distance a sound wave travels in a given time.

The phenomenon where multiple echoes, arriving at slightly different times, create a distorted, uneven sound field, affecting sound clarity.

The ability of a material to absorb sound energy, preventing reflections.

The ability of a material to reflect sound energy back into the room, enhancing loudness.

The science of designing spaces to ensure optimal sound transmission and reception, considering factors like reverberation, absorption, and reflection.

The speed of sound in air is calculated using a formula that takes into account the properties of air. This formula was initially proposed by Newton, but later corrected by Laplace.

The formula for speed of sound in air is v = √(γP/ρ), where v is the speed of sound, γ is the adiabatic index, P is the pressure, and ρ is the density of the air.

The adiabatic index (γ) is a ratio of specific heats for a gas, representing the change in heat capacity at constant pressure (Cp) and constant volume (Cv). It's a measure of how well a gas can store energy.

The speed of sound in air is affected by factors like temperature, humidity, and the presence of wind. These factors influence the density and properties of the air, which in turn affects the speed of sound waves.

An enclosed box of rigid walls with constant density air will have a pressure change when heated. The speed of sound in this enclosed air will be affected by this pressure change.

When the pressure of air enclosed in a rigid box changes, the speed of sound will change proportionally. This means if pressure increases, the speed of sound will increase.

The speed of sound is directly proportional to the square root of the absolute temperature. Doubling the absolute temperature will increase the speed of sound by the square root of 2.

The speed of sound changes based on altitude, with higher altitudes generally having lower speeds. This is due to changes in air density and temperature.

A wave that travels through a medium and causes particles in the medium to oscillate in the same direction as the wave's motion. Examples include sound waves in air.

A wave that travels through a medium and causes particles in the medium to oscillate perpendicular to the direction of the wave's motion. Examples include light waves and water waves.

The speed of sound in a medium is determined by the medium's elasticity and density. The more elastic and less dense the medium, the faster the sound travels.

The frequency of a wave is the number of complete cycles of the wave that pass a given point per second. It's measured in Hertz (Hz).

The period of a wave is the time it takes for one complete cycle of the wave to pass a given point. It's the inverse of frequency.