Learn the Units
1Light things → grams.
A crisp packet is about 25 g; a slice of bread about 40 g.
2Heavier things → kilograms.
A bag of sugar is 1 kg; school bags are 3–5 kg.
3The key fact.
1000 grams = 1 kilogram. ('kilo' means a thousand.)
Worked Example
Estimate, then choose the sensible mass.
Watch Out! Common Mistakes
Everyday note: scientists call this mass; shops say “weight”. At KS2, both words point to grams and kilograms — just use g and kg correctly.
Wrong! 1000 g = 1 kg. (100 g is just a small apple.)
Wrong! Size isn’t mass. A 9 g coin outweighs a 3 g balloon.
⬇ Cheat Sheet
- 1000 g = 1 kg.
- Grams: snacks, fruit, letters.
- Kilograms: bags, people, furniture.
- Bigger doesn't always mean heavier.
📖 Continue Your Journey
Quick summary
- Mass is measured in grams (g) and kilograms (kg); 1000 g = 1 kg.
- Anchors: a paperclip is 1 g, an apple 100 g, a bag of sugar 1 kg.
- Bigger doesn't mean heavier — a balloon is lighter than a coin.
- 'Kilo' means a thousand of the base unit.
Frequently asked questions
What is the difference between grams and kilograms?
A kilogram is 1000 grams. Grams suit light objects (an apple is about 100 g); kilograms suit heavier ones (a bag of sugar is 1 kg).
What everyday objects help children estimate mass?
A paperclip (1 g), a small apple (100 g), a bag of sugar (1 kg) and their own body mass (a 9-year-old is around 30 kg).
Is mass the same as weight?
Strictly, mass is the amount of matter and weight is the pull of gravity on it — but at primary level 'weight' in everyday talk means mass in g and kg.
Continue your child's learning journey
with the MindBlaze app.
Fun daily learning missions for children. Clear progress insights for parents — helping every child start secondary school ready to learn.
