Periodic Motion

  • Periodic motion is performed, for example, by a rocking chair, a bouncing ball, a vibrating tuning fork, a swing in motion, the Earth in its orbit around the Sun, and a water wave.


  • A wave transfers energy through a medium, without needing to transfer objects
  • Wave can be thought of as a disturbance or oscillation that travels through space-time, accompanied by a transfer of energy.
  • Wave motion transfers energy from one point to another, often with no permanent displacement of the particles of the medium —that is, with little or no associated mass transport.

Transverse Waves

  • A transverse wave is a moving wave whose oscillations are perpendicular to the direction of the wave. A simple example is given by the waves that can be created on a horizontal length of string by anchoring one end and moving the other end up and down.
  • Transverse Waves are like a guitar string

Longitudinal Wave

  • Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of propagation of the wave. 
  • Longitudinal Waves are like a slinky or spring


  • Oscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. The term vibration is precisely used to describe mechanical oscillation. Familiar examples of oscillation include a swinging pendulum and alternating current.
  • The oscillations of the wave are in the same direction as the motion of the wave


  • The amplitude of a wave refers to the maximum amount of displacement of a particle on the medium from its rest position. In a sense, the amplitude is the distance from rest to crest. Similarly, the amplitude can be measured from the rest position to the trough position.


  • Wavelength is the distance between identical points in the adjacent cycles of a waveform signal propagated in space or along a wire. In wireless systems, this length is usually specified in meters, centimeters, or millimeters.


  • Wave phase is the offset of a wave from a given point. When two waves cross paths, they either cancel each other out or compliment each other, depending on their phase. These effects are called constructive and destructive.


  • It is the time between repeated cycles


  • It is the number of cycles per second

Wave Velocity

  • Wave velocity in common usage refers to speed, although, properly, velocity implies both speed and direction. The velocity of a wave is equal to the product of its wavelength and frequency (number of vibrations per second) and is independent of its intensity.
  • Velocity is determined by the medium the wave is in


  • Sound is waves of pressure through a medium


  • Light is waves of electromagnetism
  • A wave that moves with velocity


  • Springs have restorative forces
  • Spring can be seen as a device that stores potential energy, specifically elastic potential energy, by straining the bonds between the atoms of an elastic material.


  • A pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position.
  • For small angles, pendulums can be considered to have restorative forces.