The amount of matter contained in an object is called mass.

• The symbol of mass is m. 
• It is the amount of stuff (atoms/molecules) in an object in any form. 
• Mass is measured in kg (kilogram).
• Top-pan Balance (ordinary balance) is used to measure the mass.
• The mass of a body is always constant everywhere in the universe. Mass is just a value (constant number).
• Your mass on the moon would be the same as your mass on the earth.
• Wherever you go in the solar system, your mass will stay the same.
• Mass is a scalar quantity and has no direction.
• The mass of a moving body is given by m = F/a or m = W/g.