Grade 1 · Unit 5: Using units of measurement

Mass

Heavier or lighter? Use a balance.

At the bazaar

At the bazaar, sellers weigh rice, fish and vegetables. They want to know how heavy things are. How heavy something is, is its mass.

Heavier and lighter

A balance has two pans. The heavier side goes down. The lighter side goes up.

Balanced

When both sides have the same mass, the balance is level. We say it balances.

Big is not always heavy

A big balloon is very light. A small stone is heavy. Size does not tell you the mass – check with a balance!

What I learnt

• I can use heavier, lighter and balances.
• I know that big things are not always heavy.