What is axis-angle?

Axis-angle is a way to describe how something turns, like when you twist a doorknob or spin a toy top.

Imagine you have a pencil. If you hold it at one end and twist it around, that’s rotation, the action of turning. Now, axis-angle helps us explain how that rotation happens.

The axis is like an invisible line around which something turns. Think of it as the stick you use to spin a fidget spinner, the stick stays still, but the spinner moves all around it.

The angle tells us how much we turn. If you twist your pencil halfway, that’s a 180-degree angle. If you give it a full spin, that’s 360 degrees, like going all the way around a circle!

So, axis-angle is just two parts: a line (the axis) and a number (the angle) that together show how something rotates. It's like giving directions for spinning, around what? and how much?