Here's why:

* Scalar quantities have only magnitude (size). Examples include:

* Speed: How fast something is moving.

* Temperature: How hot or cold something is.

* Mass: How much matter an object contains.

* Vector quantities have both magnitude and direction. Examples include:

* Velocity: How fast something is moving and in what direction.

* Displacement: The change in position from one point to another, including direction.

* Force: A push or pull with both strength and direction.

In summary:

* Speed tells you how fast something is moving.

* Velocity tells you how fast something is moving *and* in what direction.