Understanding Wave Motion: Types, Properties, and Sound

Understanding Wave Motion

Wave motion is a form of energy transmission that is not accompanied by the transport of matter. It is the propagation of a vibration, i.e., the propagation of movement around the equilibrium position of a body.

A wave is the position taken at each instant by the disturbance that has occurred.

Types of Waves

• Mechanical waves originate when a disturbance occurs in an elastic medium, which would not exist without the spread.
• Electromagnetic waves, although they may be transmitted through certain media, do not necessarily need an elastic medium and can propagate in a vacuum.

Wave Characteristics

• In longitudinal waves, the vibrations of particles around their equilibrium point occur in the same direction in which the wave propagates. Longitudinal waves are produced by compression and expansion between the vibrating particles.
• In transverse waves, the vibrations of particles around their equilibrium point occur in a direction perpendicular to the wave propagation.

Wave Properties

• A wave front is the line or surface consisting of points that have been reached by the perturbation at the same instant.
• A beam is defined as the imaginary line perpendicular to the wave front.
• The speed of propagation (v) is the distance the wave travels in each unit of time.
• The wavelength is the distance between two successive points of a wave that vibrate in an identical manner. It is expressed in meters.
• The period (T) is the time it takes for the disturbance to travel a wavelength. It coincides with the time it takes for a point to make a complete vibration. It is expressed in seconds.
• The frequency (f) is the number of vibrations a point makes per unit of time. Its unit is the hertz (Hz), which means "per second."
• The amplitude (A) is the peak separation reached from the equilibrium position by each of the points of the medium.
• The intensity (I) of a wave motion is the amount of energy flowing through a unit area perpendicular to the direction of propagation per unit of time. It is equivalent to the power expressed per unit of surface, in W/m².

Wave Phenomena

• Reflection is the change of direction experienced by a wave train upon collision with a smooth surface without crossing it.
• Refraction is the change in velocity experienced by a wave train moving from one medium to another of different depth or density.
• Diffraction is the phenomenon that occurs when a wave changes its propagation direction when it encounters an obstacle or an opening smaller than or equal to its wavelength.

Sound as a Wave

Sound originates from the vibration of bodies. Sound is a mechanical wave because it needs a material medium for its propagation, and it is a longitudinal wave because the particles of the medium vibrate in the same direction as the wave propagates, emitting sound energy.

Sound travels in a single homogeneous medium at a constant speed, i.e., with uniform motion.