Weight & Mass
Science: KS3, topic 3.5.14
Mass and Weight
Mass and weight differ. Mass is the amount of matter of an object. Mass is measured in kilograms (kg). Weight depends on the gravitational pull on an object. Weight is measured in Newtons (N).
Mass
- Mass comes from the Greek maza, meaning ‘lump’.
- An object will have the same mass wherever the object is.
- An object can be big.
- A big object does not always have a large mass.
How much mass?
- Mass is how much ‘matter’ there is in an object.
- Mass is measured in grams (g) or kilograms (kg).
- 1,000 grams = 1kg.
- 1,000kg = 1t (tonne).
Weight
- Weight depends on the mass of an object and gravity.
- Weight is measured in Newtons (N), after Isaac Newton.
- Weight is a force.
Weighing Scales
- You weigh yourself on scales.
- You are actually measuring your mass, not your weight.
- Weight is the force you exert on the bathroom scales.
Test yourself on Weight & Mass
What are the units of weight?
Which of these are true of mass and weight?
A large foam block and a small steel block both have a mass of 2 kg. On Earth, which has the greater weight?