# Distinguish between rotation and revolution

Rotation refers to the spinning of an object around its own axis, while revolution refers to the movement of an object around another object or a central point. For example, the rotation of the Earth causes the change in day and night, while its revolution causes the change in seasons. Another example, the rotation of a satellite around its own axis, and the revolution of that satellite around the planet it orbits.

### What is rotation?

Rotation is the spinning of an object around its own axis. It refers to the movement of an object in which it turns around a central point, also known as the axis of rotation. The axis of rotation is always fixed and passes through the center of mass of the object. Rotation causes changes in the object’s orientation, such as day and night. It is a movement within the object’s own reference frame and is caused by an internal force such as angular momentum. The period of rotation is the time it takes for the object to make one complete spin around its axis, it can be measured in units of time, such as seconds, minutes, or hours. Rotation can be clockwise or counterclockwise and can cause precession, nutation, and wobbling. Rotation is observed in objects as small as atoms and as large as galaxies.

### What is revolution?

Revolution refers to the movement of an object around another object or a central point. It is the orbit of one object around another, such as the movement of a planet around the sun, or a satellite around a planet. The axis of revolution can be any line that connects the center of mass of the object with the center of the orbit. Revolution causes changes in the object’s position, such as seasons and the relative position of the object with respect to the central point. It is a movement relative to an external reference frame and is caused by an external force, such as gravity. The period of revolution is the time it takes for the object to make one complete orbit around the central point, it can be measured in units of time, such as days, years, or centuries. Revolution is always in the same direction and does not cause precession, nutation, or wobbling. Revolution is observed mainly in celestial bodies like planets and moons.

### Differences between rotation and revolution

• Rotation is the spinning of an object around its own axis, while revolution is the movement of an object around another object or a central point.
• The axis of rotation is always fixed and passes through the center of mass of the object, while the axis of revolution can be any line that connects the center of mass of the object with the center of the orbit.
• Rotation causes changes in the object’s orientation, such as day and night, while revolution causes changes in the object’s position, such as seasons.
• Rotation is a movement within the object’s own reference frame, while revolution is a movement relative to an external reference frame.
• Rotation is caused by an internal force, such as angular momentum, while revolution is caused by an external force, such as gravity.
• The period of rotation is usually shorter than the period of revolution.
• Rotation can be clockwise or counterclockwise, while revolution is always in the same direction.
• Rotation can cause precession, nutation, and wobbling, while revolution does not.
• The amount of rotation can be measured in degrees, while the amount of revolution is measured in distance or time.
• Rotation is observed in objects as small as atoms and as large as galaxies, while revolution is observed mainly in celestial bodies like planets and moons.

### Note about rotation and revolution of the earth on the sun

The Earth rotates on its own axis, which is an imaginary line that runs through the North and South poles. This rotation causes the change in day and night, with one complete rotation taking approximately 24 hours. This rotation also causes the Earth’s seasons, as the tilt of the Earth’s axis causes different parts of the planet to receive different amounts of sunlight throughout the year.

The Earth also revolves around the sun, following an elliptical orbit. This revolution causes the change in seasons, as the Earth is closest to the sun during the northern hemisphere’s winter and farthest from the sun during the northern hemisphere’s summer. One complete revolution around the sun takes 365.24 days, which is why we have a leap year every four years to account for the extra fraction of a day.

### Example for rotating objects

1. The Earth rotates on its own axis, causing the change in day and night.
2. A fan rotates around its own axis to create a cooling breeze.
3. A washing machine, which rotates clothes inside to clean them.
4. A car tire rotates to provide traction and enable the car to move.
5. A top spins around its own axis as it moves across a surface.
6. A spinning ice skater rotates on the spot by using their arms to increase or decrease rotation speed.
7. A turbine in a power plant uses the energy from a steam or gas flow to rotate and generate electricity.
8. A planet’s magnetic field is generated by the rotation of its liquid core.

### Examples for revolution objects

1. The Earth which revolves around the sun causes the change in seasons.
2. The Moon, which revolves around the Earth, causes the tides and lunar phases.
3. A satellite revolves around a planet, such as a communications satellite orbiting Earth.
4. A planet, which revolves around a star, such as the Earth orbiting the sun.
5. A comet, which revolves around the sun, follows an elliptical orbit.
6. An asteroid, revolves around the sun, following an elliptical orbit.
7. A binary star system is where two stars revolve around a common center of mass.
8. Moons of Jupiter, Saturn, Uranus, and Neptune revolve around their respective planet