Education

Difference between Rotation and Revolution

Main Difference

Many terms that are common in the way they get used and have similar meanings, create confusions among people, and therefore it gets important to clarify them with the help of examples and theory. The two terms getting discussed here are rotation and revolution, and both have their definitions. Key differences between them come from the way they move in the surroundings and forms the basis. The rotation gets defined as the circular movement of an object around a fixed point or axis. Whereas, Revolution gets defined as the circular flow of an object around an external axis.

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Comparison Chart

Basis of Distinction Rotation Revolution
Meaning To spin To go around something.
Definition The circular movement of an object around a fixed point or axis. The circular movement of an object around an external axis.
Fact Causes different time zones around the world. Causes different seasons around the world.
Example Earth revolving around is own axis and does so every day. Earth is revolving around the sun, and it takes around 365 days to complete the process.
Speed Maximum at its own axis whereas it is minimum around the poles. Fastest when the sun is around the earth and slowest when the Earth is away from the sun.
Axis Axis of rotation is internal Axis of rotation is external
Position The position of object does not change as the axis is fixed. The position of object keeps on changing since the axis is independent.
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Rotation

The rotation gets defined as the circular movement of an object around a fixed point or axis. It is the motion around the object’s center, and the mass gets equally disturbed so that every point of the body moves in a circle this axis of rotation. The center of mass, therefore, gets defined as the place from where each point has equal quantity of mass in all the directions. The axis around which all the action takes place is the one that passes through the center of mass and divides the object equally in two opposite directions. This term gets more explained in such a way that when something starts to move about a fixed point, the distance it travels does not count in the movement they have made linearly, but it is the angle at which the motion takes place. For example, if a body has moved at an angle of 90 degrees then we will say that it has moved a quarter of a circle. Similarly, it if moves 180 degrees we will say that it has moved half the circle length. Rotational motion is not that difficult to achieve, as long as the force gets applied anywhere on the object except for the center of mass, it will start moving. Inertia is present whenever this phenomenon takes place but is more complicated than a body traveling at a distance.

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Revolution

Revolution gets defined as the movement of an object in a circular motion around the center of another body or around its center. This motion does not have to be circular at all times, but the elliptical formation is also possible. For a three-dimensional case, when the object moves around a line that does not exist, then this line is called the revolution axis, if it passes through the center of the mass, then the revolutions take place around itself. The best example of this case gets explained as when the object moves around the other body. The earth revolves around the sun and does so with an external axis, the sun acts as the primary source, and everything including the earth moves around it. Similarly, for the moon, the earth serves as an external axis of rotation. When the earth moves about its axis, then the action is rotation, but when the earth moves around the sun it is called a revolution. There are many other ways of explaining the difference between these two terms. Revolution is also used in mathematics and therefore has a widespread usage. When a body moves full 360 degrees, this gets termed as a rotation, but when the action is how many times the process occurred according to the external source then the word becomes a revolution and gets measured in revolutions per minute or RPM.

Key Differences

  • The wordily meaning of the term rotation is to spin whereas the wordily meaning of the word revolution is to go around something.
  • The rotation gets defined as the circular movement of an object around a fixed point or axis. Whereas, Revolution gets defined as the circular circulation of an object around an external axis.
  • An example of the term rotation is the earth revolving around is own axis and does so every day whereas the case in term revolution is the earth revolving around the sun and it takes around 365 days to complete the process.
  • Rotation is the reason there are various time zones in the world, and each country has their own. Revolution is the reason there is a different season in the world with some having winter and others having summer.
  • The speed of rotation is maximum at its own axis whereas it is minimum around the poles. The rate of revolution is fastest when the sun is around the earth and slowest when the Earth is away from the sun.
  • The axis of rotation is always internal whereas the axis of revolution is always external.
  • No change in position takes place for a rotation whereas there is a change of position when the revolution takes place.

Video Explanation