A disturbance that results in a wave is caused by a physical change or force that alters the state of a medium or field. This disturbance can be:
- A local deformation or change in a physical medium, such as the surface of water being disturbed by a rock thrown into a pond or a swimmer splashing
- A change in air pressure, such as the oscillation of a speaker cone that creates sound waves
- Accelerating charges that cause oscillations in electric and magnetic fields, producing electromagnetic waves
- Physical vibrations or forces like wind blowing over the surface of water, generating water waves, or movements of the Earth's crust causing tsunamis
In essence, a wave begins when a force or event causes a measurable change- such as displacement, pressure, or field strength-in a medium or field. This disturbance then propagates through the medium by transferring energy from particle to particle or through oscillations in fields, creating the wave phenomenon
. Thus, the cause of the disturbance that results in a wave depends on the type of wave but generally involves some initial force or change that disrupts the equilibrium state of the medium or field.
