Definition
Mass
Mass measures how much matter an object contains.
What it means
A balance compares mass. A school bag has the same mass on Earth and on the Moon, even though gravity would make its weight different.
Remember it
Mass stays with the object; weight depends on gravity.
Example
Three 250 g packs of rice have a total mass of 750 g. This is 0.75 kg because 1,000 g = 1 kg.
Watch for
In everyday speech, people often say “weight” when they mean mass; in mathematics and science, grams and kilograms measure mass.
Common mix-up
Mass is not how hard gravity pulls on an object; that force is weight.
Exact meaning
Mass is a property of an object that measures its amount of matter. It is commonly measured in grams (g) and kilograms (kg), and unlike weight, it does not change when the strength of gravity changes.