Sound Waves

Sound is a mechanical disturbance that propagates through an elastic material medium from a condition of equilibrium. A purely subjective definition of sound, as that which is perceived by the ear, is also possible, but this definition is not particularly illuminating and overly restrictive, because it is useful to speak of sounds that are not audible to the human ear, such as those produced by dog whistles or sonar equipment.

The properties of sound waves should be the starting point for any study of sound. There are two fundamental types of waves: transverse and longitudinal, which are distinguished by how they propagate. The motion that makes up a transverse wave, such as the one created when one end of a stretched rope is wiggled back and forth, is perpendicular or transverse, to the direction (along the rope) in which the wave is traveling. 

Electromagnetic sources, such as light or radio, produce a large family of transverse waves in which the electric and magnetic fields that make up the wave fluctuate perpendicular to the propagation direction.

Sound

In physics, sound is a vibration that travels through a transmission media such as a gas, liquid or solid as an acoustic wave

Only acoustic waves with frequencies in the audio frequency range (about 20 Hz to 20 kHz) elicit an auditory perception in humans. These are sound waves with wavelengths ranging from 17 meters (56 feet) to 1.7 centimeters in air at atmospheric pressure. Ultrasound is defined as sound waves with a frequency greater than 20 kHz that are inaudible to humans. Infrasound is defined as sound waves with a frequency below 20 Hz. The hearing ranges of different animal species differ.

The definition of sound is Pressure, stress, particle displacement, particle velocity and other oscillations propagated in a medium having internal forces (e.g., elastic or viscous) or the superposition of such oscillations.  Sound can be viewed as a wave motion in air or another material. Sound is a stimulus in this scenario. Sound can also be considered as an excitation of the hearing system that causes sound perception. Sound is a sensation in this scenario.

Sound Waves

Compression and rarefaction patterns make up sound waves. When molecules are densely packed together, compression occurs. On the other hand rarefaction occurs when molecules are separated from one another. 

It’s crucial to remember that molecules do not move with sound waves. The molecules become supercharged and migrate away from their original places as the wave passes. The movement of a molecule decreases as it transfers its energy to neighboring molecules until it is influenced by another passing wave.

Compression and rarefaction are caused by the wave’s energy transfer. There is high pressure during compression and low pressure during rarefaction. A sound wave’s wavelength is made up of one compression and one rarefaction.

As sound waves travel across a medium, they lose energy, which explains why you can’t hear individuals conversing far away yet can hear them whispering close by. Sound waves are reflected by materials such as walls, pillars and rocks as they travel across space. An echo is the term for this type of sound reflection. You’ve probably heard your echo travel far further than usual if you’ve ever been inside a cave or canyon. This is because the massive rock walls bounce your sound back at you.

Types of Sound Waves

Generally there are two types of Sound Waves:

Longitudinal waves

A longitudinal wave arises when the motion of the medium’s particles is parallel to the energy transport direction. Because the particles that convey sound vibrate parallel to the sound wave’s travel direction, sound waves in air and fluids are longitudinal waves. Similarly, when a tuning fork is struck, the sound wave travels in the same direction as the air particles.

Transverse Wave

Transverse waves have oscillations that travel perpendicular to the wave’s direction. Sound waves are not transverse waves since their oscillations are parallel to the direction of energy transmission; yet, in extremely specific situations, sound waves can become transverse waves. Transverse waves, also known as shear waves, travel at a slower rate than longitudinal waves and can only be produced in solids. The most common example of transverse waves in nature are ocean waves.

Nature and characteristics of Sound wave

Sound waves are generally longitudinal waves.

Longitudinal waves describe sound waves in the air (and any other fluid medium). Sound waves cause particles in the medium through which the sound is transmitted to vibrate in a direction parallel to the sound wave’s movement.

Characteristics

Wavelength

The wavelength is the shortest distance over which a sound wave can repeat itself. It is, in other words, the length of a single complete wave. A Greek letter is used to represent it (lambda). The total length of a compression and a subsequent rarefaction of a sound wave is known as its wavelength.

Amplitude

When a wave travels through a medium, the medium’s particles are temporarily displaced from their original, undisturbed places. When a wave passes through a medium, the amplitude of the wave is the maximum displacement of the particles from their initial undisturbed positions. The amplitude, in reality, is used to indicate the wave’s size. The meter (m) is the SI unit of amplitude measurement, however it is sometimes measured in centimeters.

Time period

The time it takes to complete a single complete wave or cycle is referred to as the wave’s time-period. One full vibration of the vibrating body now produces one complete wave. As a result, the time it takes to complete one vibration is referred to as time-period. It is represented by letter T.  Second is the unit of time period measurement (s).

Frequency

The frequency of a wave is defined as the number of complete waves or cycles produced in one second. The number of vibrations per second is called frequency because one entire wave is produced by one full vibration of the vibrating body. Its SI unit is hertz or Hz.

Conclusion

In this article we have studied sound, sound waves and their characteristics. Sound is the sensation that our ears perceive. It is a type of energy that allows us to hear. In our daily lives, we hear a variety of sounds.

A wave is a vibratory disturbance in a medium that transports energy from one point to another without the two points coming into direct contact. A wave is created by the vibrations of the particles of the medium through which it travels.