Here's why:

* Speed tells you how fast something is moving.

* Direction tells you which way it's moving.

Example:

* Speed: A car is traveling at 60 mph.

* Velocity: A car is traveling at 60 mph north.

Key Point: Velocity is a vector quantity, meaning it has both magnitude (speed) and direction.

In contrast:

* Speed is a scalar quantity, meaning it only has magnitude.