Distance: Measurement of the gap between two points in certain units is called distance. Measurement: Measurement means the comparison of an unknown quantity with some known quantity. Motion: It is a state of objects in which they are moving that is, they are changing their place with time. Motion and Measurement of Distances is a whole chapter that deals with transport, measurements, standard units of measurements, length measurement, measurement of the length of a curved line, movement of things around us and types of motions.