Mass is a property of matter. It does not depend on temperature, pressure and location of the body in space. Mass of a body is defined as the quantity of matter contained in a body. The SI unit of mass is kilogram (kg). The masses of objects which we shall study in this course vary over a wide range. These may vary from a tiny mass of electron (9.11×10−31kg) to the huge mass of the known universe (=1055 kg). The order of masses of various objects is shown in Table 1.6.
Ordinarily, the mass of an object is determined in kilograms using a common balance like the one used in a grocery shop. For measuring larger masses like that of planets, stars etc., we make use of gravitational methods.
For measurement of small masses of atomic/subatomic particles etc., we make use of a mass spectrograph.
Some of the weighing balances commonly used are common balance, spring balance, electronic balance, etc.