Wave Science

Introduction

Wave research is the study of waves, their properties, and the different ways in which wave energy can be used. A wave is the transfer of energy from one point to another through medium particles. The movement of energy does not entail a change of direction, but rather a relocation of the particles from rest to another location and back to rest. Wave propagation returns all particles in the medium to their original location prior to energy transfer. A wave has a velocity that is a part of both frequency and wavelength.

Frequency and Wavelength

Frequency is the number of oscillations the medium particles undergo per unit time during wave propagation (Mason). Wavelength is the distance between two successive peaks of a wave. As a wave propagates through a medium, the particles initially at rest are displaced to a higher altitude (A) whose peak is referred to as a trough. As the energy moves to adjacent particles, the particles at the trough falls to a lower altitude whose lowest point is called the crest (Chernov). The difference between two successive troughs of a sinusoidal wave is known as the wavelength.

Wave Parameters

The important wave parameters include the amplitude, wavelength, period, phase, velocity, wave number, time t, plane coordinates, and the frequency propagation. When a wave propagates through a medium, the particles of the medium are displaced from a different height above the reference zero. The difference in height between the peak and the reference zero is referred to as the amplitude of the wave (Atanackovic et al). The distance between two successive troughs or crests is known as the wavelength of the wave. A period is a time taken for a complete to cross a certain point during propagation. Obtaining mathematical inverse of the period (1/T) yields the frequency of the wave. Besides, the frequency can be described as the count of complete waves that go through a certain point along the medium of propagation. The speed of the wave is measured as meters per second and is the rate of movement of a given point of a wave during propagation. Waves can be categorized depending on the shape of the wave fronts formed during propagation.

Categories of Waves

There are three categories which include standing waves, plane waves, and sinusoidal waves. Standing waves are also referred to as stationary waves and are formed when a wave moves in an opposite direction to that of the medium (Brillouin). The standing waves can also be formed when two waves are travelling in opposite direction within the same medium. A combination of the two waves moving in opposite direction forms a standing wave. Sinusoidal waves are formed when a wave assumes a repetitive oscillation along the plane of propagation. Plane waves are one whose surfaces propagate at a constant phase.

Wave Properties

Waves exhibit physical characteristics when investigated under controlled or standard conditions. The properties include absorption, reflection, refraction, propagation, interference, diffraction, dispersion, and polarization. Waves are absorbed by particles of the medium they encounter during propagation. The particles absorb the energy of the wave and they begin to oscillate at the same frequency of the wave. Absorption occurs when the frequency of the wave coincides with the natural frequency of the material particles. The natural frequency is the rate of oscillation of the particles when they are in their natural setting without interference from internal or external forces. Waves show the reflection characteristic when they strike a material and bounce back to the same or different direction of propagation (Chernov). When all the energy of a wave is reflected back by a medium the condition is referred to as total reflection. If some of the wave energy is lost and the other part is reflected back to the medium the phenomenon is known as partial reflection.

Interference and Refraction

Interference is a property of the waves which happens when two waves are in or out of phase with one another. There are two types of interference namely constructive and destructive interference. Constructive interference occurs when two waves travelling in the same direction and in the same medium are in phase. The altitude of the two waves combine and the altitude (A) of the resultant wave is larger than any of the two constituent waves. Destructive interference occurs when two waves moving in the same direction and in a common medium of propagation are out of phase. The altitude (A) of the resultant wave is less than those of the constituent waves. Refraction is another property exhibited by a wave when it changes speed as it propagates through a different material medium (Brillouin). When a wave undergoes refraction, the phase velocity changes and the phenomenon occurs at the boundary of one medium and another in which the wave propagates. The measure of refracted wave is indicated by a standard number referred to as the refractive index. Each existing material has its own measure of refractivity which indicates the degree of refraction a propagating wave will undergo. Snell's law relates the angle of incidence and refraction to the refractive indices of a material medium.

Diffraction and Polarization

Diffraction is a property exhibited when a wave as it emerges from a small opening or when it encounters an impediment that causes it to change the direction of propagation. Also, diffraction occurs when a wave moves round a corner. Polarization characteristic is manifested when the motion of the wave occurs in two planes that are perpendicularly separated. Transverse Waves exhibit polarization but longitudinal waves do not. Polarized waves travel in the same direction of propagation. Dispersion occurs when the group or phase velocities is depended on the frequency of the propagating wave. A wave is dispersed when it passes through a material medium that subdivides it into smaller waves of different frequencies (Chernov). For instance, when white light is allowed to pass through a prism it is dispersed into seven colors each with a different wavelength.

Types of Waves

There are different types of waves such as electromagnetic waves, mechanical waves, gravity waves, gravitational waves, and quantum mechanical waves. An example of mechanical waves includes seismic waves, shock waves, water waves, acoustic waves, and waves formed on strings. Electromagnetic waves are able to travel in a vacuum and constitute both magnetic and electric fields. An example of electromagnetic waves includes radio waves, X-rays, Ultraviolet (UV) rays, Gamma rays, infrared, and microwaves (Ferreira and Moisan). The direction of propagation of an electromagnetic wave is perpendicular to the direction of oscillation of both electric and magnetic fields. In a vacuum, the electromagnetic waves move at the speed of light which is 3exp8 m/s. Quantum mechanical Waves exhibit properties that resemble that of particles. According to Schrodinger's equation, particles of a medium are able to show wave-like characteristics. Gravity waves are exhibited in a fluid medium when the particles are displaced and equilibrium is restored through buoyancy. Gravitational waves are different from gravity waves since the former travels through space while the latter requires a fluid material medium to propagate. Mechanical waves are waves that are generated through mechanical means such as water or sound waves. There has to be a force that initiates the mechanical waves so that they may propagate through the material medium (Brillouin).

Wave Characteristics

Waves are also categorized depending on the special characteristics they exhibit. The characteristics depend on the orientation of the material medium particles when the wave is propagating. The categories include longitudinal waves, transverse waves, and surface waves. In a longitudinal wave, the particles move parallel to the direction of the energy. The wave comprises of compressions and rarefactions. A compression of a longitudinal wave is the point at which the frequency of the wave increases and the wavelength decreases. A rarefaction occurs when the frequency of the wave decreases but the wavelength increases. A combination of rarefactions and compressions in a longitudinal wave facilitate the transfer of energy from one point to another through a material medium. The wavelength of a longitudinal wave is the distance between two successive compressions or rarefactions. In a transverse wave, the particles of the material medium move in a direction perpendicular to that of propagating energy. A transverse wave comprises of troughs and crests. Troughs are the peak points of a wave while the minimum points of the wave are referred to as the crests. The wavelength of a transverse wave is the distance between one trough and the adjacent other (Atanackovic et al). The wavelength can also be measured between two successive crests of the wave. In a surface wave, the particles of the material medium move in a circular motion. Only the particles on the surface move in a circular motion while the rest of the particles of the medium do not move during wave propagation. Similar to transverse waves, a surface wave has crests and troughs too. The wavelength of a surface wave is the distance between two adjacent troughs or crests. A surface wave occurs at the interface of two material media. The particles of the medium in a surface wave moves both in perpendicular and parallel directions (Zuo, Min, and Spence 26). The movement occurs simultaneously hence it is described as being circular.

Applications of Waves

Waves are useful to the existence of human beings and there are many applications of wave characteristics and energy. The importance of using waves is that they can be found everywhere around the world and what matters is the technology used to harness it. Efficient methods of harnessing wave energy ensure that less risk is incurred during the utilization process. There are many devices using wave science such as microwave ovens, Television (TV) and radio signal transmission, different forms of communication, movie shooting and recording, music players, cameras among others (Zuo, Min, and Spence 21). Microwave oven using microwaves to cook and warm food within a short period of time. A device is placed inside the microwave oven that converts electrical energy into waves with the frequency of microwaves (Ferreira and Moisan). The emitted microwaves are contained in the oven with carefully selected materials to avoid harm to the users. The energy carried in the microwaves are absorbed by the food which then gets heated. Wave frequencies are used in communication between two people in different regions using communication devices. Electromagnetic waves are used for communication purposes to ensure sound or image characteristics are transmitted from one point to another (Mason). The communication devices use a low frequency sound or picture signal to modulate a high frequency carrier wave. The significance of electromagnetic waves in communication is the ability to propagate through space and air medium with minimal interference. Seismic waves are used to detect an incoming earthquake or catastrophic tidal waves and ensure safety measures are taken to keep residents in the region safe from the disaster. In hospitals, shock waves are used to resuscitate a patient whose heart is on the verge of seizing to pump blood. Medical practitioners use a device that produces a specified amount of shock energy that is not fatal to make the heart start beating again or continue beating at a normal rate. Ultrasound waves are used by oil explorers to predict the presence of oil reserves in the ocean floor. Ultrasound waves are also used to determine the distance between one point and another when it is difficult to use conventional methods (Lim, Zhang, and Reddy 301). Sound waves are used in communication between human beings. A person produces sounds of specific frequency ranges known as the vocal range in which other human beings are able to hear. Birds and other animals utilize sound waves to communicate to each other or send warning signals in case of invading predators. Dogs use sound waves to communicate to human beings or sound alerts when an intruder approaches a restricted area. In advanced technologies, compression waves are used to detect tremors caused by an explosion before the sound from the explosion reaches the ears of people within the region (Lim, Zhang, and Reddy 306). This is because compression waves travel at a higher speed in solids as compared to air medium. Acoustic engineers use the knowledge of sound waves to construct soundproof rooms or barricades. In the music industry, different instruments are used to produce a combination of sounds that make beats of a music. Sound diffraction is used in spying or eavesdropping conversations of people without being seen.

Conclusion

In conclusion, wave science is the study of characteristics of different types of waves and is a crucial field in the existence of human kind. A wave is the oscillation of material medium particles that facilitates the transfer of energy from one point to another. Knowledge of the waves is used in designing technological devices that can be used in communication, transport, oil explorations, and security systems among others. There are various characteristics of a wave such as its wave number, period, frequency, velocity, wavelength, amplitude, phase, time of propagation, and plane coordinates. Movement of particles in the wave can be used to categorize waves into longitudinal, transverse, and surface waves. Depending on the medium of propagation, waves can be grouped into electromagnetic waves, mechanical waves, gravity waves, gravitational waves, and quantum mechanical waves. Some of the waves such as electromagnetic waves are able to travel through a medium. There are numerous applications of wave science such as in the manufacture of devices for security systems, communication purposes, industrial production, automobile industry, nuclear power production, airplane control systems, military purposes, and for matters of national security such as control of weapons of mass destruction.

Works Cited

Atanackovic, Teodor M., et al. Fractional calculus with applications in mechanics: wave propagation, impact and variational principles. John Wiley & Sons, 2014.

Brillouin, Léon. Wave propagation and group velocity. Vol. 8. Academic Press, 2013.

Chernov, Lev A. Wave propagation in a random medium. Courier Dover Publications, 2017.

Ferreira, Carlos M., and Michel Moisan, eds. Microwave discharges: fundamentals and applications. Vol. 302. Springer Science & Business Media, 2013.

Lim, C. W., G. Zhang, and J. N. Reddy. "A higher-order nonlocal elasticity and strain gradient theory and its applications in wave propagation." Journal of the Mechanics and Physics of Solids 78 (2015): 298-313.

Mason, Warren P., ed. Physical acoustics: principles and methods. Academic press, 2013.

Zuo, Jian Min, and John CH Spence. "Electron Waves and Wave Propagation." Advanced Transmission Electron Microscopy. Springer New York, 2017. 19-47.