Rotation and Revolution 17,908 views
It is important to understand the difference between rotations and revolutions. When an object turns around an internal axis (like the Earth turns around its axis) it is called a rotation. When an object circles an external axis (like the Earth circles the sun) it is called a revolution.
Let's talk about rotation and revolution. A lot of people confuse a rotation and a revolution. They talk about you know the earth rotating around the sun that's not really an accurate term to use in terms of the relationship between the earth and the sun. So let's talk about these terms and give some examples and try to clarify what the difference is. So first off we have a rotation is an object that's turning around its own axis and a term that might simplify that is spin. So I spin a top and it spins around its axis okay. Revolution is a little different right revolution is an object turning around another object or sometimes they say an external axis okay so another word for that would be like an orbit. So the earth revolves around the sun it doesn't rotate around the sun but moon revolves around the earth.
Okay, so let's kind of clarify. So if we're talking about the earth and we're talking about the earth's rotation we're talking about its spinning around its axis right. It does that rotation once every 24 hours, 1 day okay. Now we talk about the earths revolution around the sun so here's our sun here and let's see the amount of time it's going to travel completely around the sun. Okay one revolution is 365 days or a year so again an example of an orbit revolving around an external axis or another object versus rotation where it's spinning around its own axis again 2 terms that are commonly confused by many students.