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

* Temperature

* Mass

* Time

* Speed

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

* Velocity

* Displacement

* Force

* Acceleration

Speed tells you how fast something is moving, but it doesn't tell you the direction. Velocity, on the other hand, tells you both how fast something is moving *and* in what direction.

Let's illustrate with an example:

* Speed: A car is traveling at 60 miles per hour.

* Velocity: A car is traveling at 60 miles per hour *north*.

The car's speed is the same in both cases (60 miles per hour), but its velocity is different because the direction is specified in the second case.