The idea, step by step
Heavy is not the same as big
Mass tells us how heavy an object is. A small stone can be heavier than a big sponge.
You can compare safe objects by holding one in each hand. Ask an adult before lifting anything heavy.
Read a balance
A balance has two pans. The heavier side moves down and the lighter side moves up.
If the pans are level, the objects balance. They have the same mass, even if they look different.
A common trap
The biggest-looking object must be the heaviest.
Instead: Compare the mass by lifting safely or using a balance. Size alone does not tell you.
See the thinking
The lower pan
The stone pan is lower in the picture. Which object is heavier?
- Find the lower pan.
- The stone is on that pan.
A level balance
A toy and a bag of blocks make the pans level. Which has more mass?
- Neither pan is lower.
- The objects balance.
Check your understanding
A pan holding a book is higher than a pan holding a box. Which object is lighter?
Show answer
The book.
The lighter pan is higher; the heavier box pan is lower.
Your turn
6 questions · Work at your own pace.
Read the questions online
- Use the balance picture. Which object is lighter?
- A ball and a block balance on level pans. Compare their masses.
- A small rock is heavier than a large empty cup. Is the larger object always heavier?
- The apple pan is lower than the feather pan. Complete: The apple is ___ than the feather.
- One box balances 4 identical blocks. Another box balances 6 of those blocks. Which box is heavier?
- Explain how a balance could help you choose the lighter of two toys.
Read the worked solutions
- Use the balance picture. Which object is lighter?
Its pan is higher.
The sponge. - A ball and a block balance on level pans. Compare their masses.
Level pans show equal mass.
They have the same mass. - A small rock is heavier than a large empty cup. Is the larger object always heavier?
This rock is smaller but heavier.
No. - The apple pan is lower than the feather pan. Complete: The apple is ___ than the feather.
The lower pan has more mass.
heavier - One box balances 4 identical blocks. Another box balances 6 of those blocks. Which box is heavier?
The blocks all have the same mass.
Six blocks are heavier than four blocks, so the box balancing six is heavier.
The second box. - Explain how a balance could help you choose the lighter of two toys.
Read the position of the pans, not the size of the toys.
Put one toy on each pan. The toy on the higher pan is lighter; if level, they have the same mass.
Curriculum reference & lesson scope
Australian Curriculum v9 / SA Curriculum 2026
Year 1 informal comparisons and measuring with uniform units; explanation and practical activity accompany fluency.
Official curriculum source ↗