Simple harmonic motion is a type of periodic oscillatory motion that occurs when the restoring force acting on a system is directly proportional to the displacement from the equilibrium position. Ideal examples of this motion include the oscillation of an ideal mass attached to a spring or the idealized swinging of a pendulum when the displacement is small. This motion can be described by a sinusoidal function, resulting in a predictable, smooth return to the center point. The frequency and period of this oscillation are dependent only on the properties of the system, such as the spring constant and the mass involved, independent of factors like the amplitude of displacement.