* Velocity is a vector: Velocity has both magnitude (speed) and direction.

* Speed is the magnitude: Speed is only the rate at which an object is moving, without specifying direction.

How speed changes velocity:

* Increasing speed: If you increase the speed of an object while keeping its direction the same, you are increasing the magnitude of its velocity.

* Decreasing speed: If you decrease the speed of an object while keeping its direction the same, you are decreasing the magnitude of its velocity.

* Changing direction: Even if the speed remains constant, changing the direction of motion will change the velocity because velocity includes direction.

In summary: While speed is a part of velocity, it's not the whole story. Changing speed or direction will always change the velocity of an object.