An oscillation is a cyclical motion which is repeated periodically in more to less regular or irregular intervals of time. Oscillating motions include all forms of vibration, fluctuation, rotation, and revolution.

A vibration is the recurrent motion of a system about its position of equilibrium.

A vibrating motion may include a simple system such as a pendulum, or a complex one such as an electric motor.

A fluctuation is the averaged motion of a volume of substance which accumulates alternately in opposite regions about a position of equilibrium, such as the periodic rise and fall of oceanic tides. In addition, a fluctuation is defined as a period of activity, separated by a corresponding period of inactivity, such as glacial and interglacial periods which occur on the Earth at periodic intervals.

Fluctuations include alternating periods of geological, biological, economic, and cultural growth and decline.

A body which vibrates or fluctuates in equal time intervals produces a regular vibration. A body which vibrates or fluctuates in arbitrary or irregular time intervals produces an irregular vibration.

For example, a heartbeat vibrates at regular intervals, while the amount of annual rainfall in a particular region of the world fluctuates at irregular intervals.

Rotational motion is the spin of a body about its axis. A rotating body spins in any of three angular directions at various time rates.

A revolving body travels about a central axis in a circular or elliptical orbit. An orbiting body such as a planet or star proceeds along an angular path in a clockwise or counterclockwise direction at a time rate which depends on the mass and density of the body, and the forces which influence it.

The amount of time in which an oscillating motion occurs depends on the distance traveled about its position of equilibrium or central axis, and its speed.

Normally, large bodies such as planets, stars, and galaxies rotate about their axes while they orbit around another, usually larger, body. Small particles such as molecules, atoms, and quarks tend to vibrate, fluctuate, spin, or revolve around a central axis.


‘When I was a boy, I used to spin a ball on the top of my finger. I liked the feel of it. I would move around the house from room to room, spining the ball, and trying not to break anything. I liked the feel of controlling and being controlled by two rotating spheres at either end of my body.’

When I lie down and face the ground, I can feel my body slowly turning on the Earth’s axis.

– J. H.