A physical system is defined by various characteristics and measurable properties. When one of these properties is disturbed, the disturbance can propagate through space.
Is disturbance propagation is what is known in physics as vibe.
For example, a wave can be produced that propagates a disturbance in the density or pressure of the medium, or a wave that propagates a disturbance in the electric field or in the magnetic field.
It's important pointing that waves carry energy but not matterIn fact, depending on the type of wave, a wave can propagate in a medium containing matter, but it can also propagate in an empty medium.
Considering these characteristics, waves are classified into two types: mechanical waves and electromagnetic waves:
- mechanical wave: is defined as a matter oscillation (position, speed and energy of its atoms) that propagates a disturbance in the mechanical properties of a material medium. Being an oscillation in matter, mechanical waves cannot be produced in a vacuum.
- electromagnetic wave: oscillation in the electromagnetic field. Electromagnetic waves can also propagate through a vacuum; they do not require a medium to propagate, although they do propagate through one.
General characteristics of mechanical waves
A mechanical wave is oscillation of matter that transfers energy through a medium. The energy is transported in the same direction in which the wave is moving.
Mechanical waves can only be produced in a medium that has elasticity and inertia and they can travel long distances, although the oscillating material moves very little from its original position.
Mechanical waves require an initial energy that produces the oscillation of matter. Once the initial energy is added, the wave travels through the medium until all the energy is transferred.
Waves are characterized by several parameters, mainly frequency, period, wavelength, and amplitude:
- Wavelength: distance between one pulse or oscillation and the next.
- Period: time elapsed between one oscillation and another.
- Frequency: number of waves that pass through the same point during a given time.
- Amplitude: in transverse waves, the amplitude is the distance that the medium moves when the wave passes.
Types of mechanical waves
The three general types of mechanical waves, depending on how the oscillation of the medium occurs, are transverse waves, longitudinal waves and surface waves.
transverse waves: the particles of the medium vibrate perpendicular to the direction of wave propagation. If the wave travels horizontally, the particles would vibrate up and down. Seismic S waves are a good example of shear waves.
longitudinal waves: the particles vibrate parallel to the direction of wave propagation. The wave consists of a series of compressions and rarefactions of the medium. Examples of this type of mechanical wave are seismic P waves and waves that propagate sound.
surface waves: surface waves occur at the surface of a medium or at the interface that separates two different media. An example of this type of waves are the waves on the surface of a swimming pool or a lake.