Here's the breakdown:

* Speed is how fast something is moving, without regard to direction. It's a scalar quantity, meaning it only has magnitude (e.g., 25 miles per hour).

* Velocity is how fast something is moving *and* in what direction. It's a vector quantity, meaning it has both magnitude and direction (e.g., 25 miles per hour *northwest*).

Example:

* A car traveling at 60 miles per hour has a speed of 60 mph.

* A car traveling at 60 miles per hour *east* has a velocity of 60 mph east.

Key takeaway: Velocity is a more complete description of motion than speed because it tells you both the rate and direction of movement.