Speed is a scalar quantity as it has magnitude, and no direction. Velocity, on the other hand, is a vector quantity as it has both magnitude and direction.
Scalars:
-- temperature; (68 degrees, no direction)
-- cost; ($37.50, no direction)
-- speed; (35 mph, no direction)
Vectors:
-- trip to the store; (2 blocks, West)
-- force of gravity; (170...