When an object is moving, it is said to be in motion. An object in motion keeps changing position every time. If an object does not change position, it is said to be at rest.
For example- A ball rolling is said to be in motion while the ball is at rest if it does not move.
There are four types of motion depending on the movement of objects.
Rectilinear motion
Circular motion
Periodic motion
Rotational motion
Measurement
When we compare known and unknown quantities, it is called measurement. WE can express measurement in units. Measurement comprises a number and a specified unit of measurement.
For example- In 1 cm, 1 is the number, and cm is the unit.
Measurement of distances
Distance is the length between any two points. The process of measuring the distance is called the measurement of distances.
Meter is the standard unit of measuring length. Centimeters, millimeters, and kilometers are also preferred to measure distances, depending on the magnitude of distances measured.
The millimeter is the unit to measure minute objects like the thickness of a thin wire.
Centimeters is the unit used to measure small things. Example- pen, eraser.
Meter is a unit to measure short distances. Example- the length of a building.
Kilometers is the unit used to measure long distances. For example, the distance between Delhi and Gujarat.
Relation between the units of measurement
1 meter =100 cm
1 centimeter = 10 millimeter
1 km = 1000 m
Learning Videos for 6th Grade Science - Motion and Measurement of Distances