The metric system story

Quick answer

The metric system is a way of measuring things using powers of ten, like 10, 100, 1000, and so on. It makes maths easier because it uses simple numbers and patterns.

Learning outcome

By the end of this page, you will understand how the metric system works and why it helps us measure things like length, weight, and capacity using simple numbers based on ten.

• You can explain why the metric system uses tens, hundreds, and thousands.
• You can convert between units like centimetres, metres, and kilometres.
• You can use the metric system to solve simple problems in everyday life.
• You can see how the metric system helps in science, cooking, and building.

Why this matters

Knowing about the metric system helps you understand how to measure things like how tall you are, how much milk you drink, or how far you walk. It’s used all over the world and helps scientists, cooks, builders, and even athletes do their jobs better. It's like having a secret code that makes maths easier!

How it works

The metric system is built on powers of ten. This means that every unit is ten times bigger than the one before it. Here’s how it works:

1. Length: millimetre (mm), centimetre (cm), metre (m), kilometre (km)
2. Weight: milligram (mg), gram (g), kilogram (kg)
3. Capacity: millilitre (ml), litre (l), kilolitre (kl)

Each step is ten times bigger than the last. For example, 10 millimetres = 1 centimetre, 100 centimetres = 1 metre, and 1000 metres = 1 kilometre.

Examples you can see

Let’s look at how the metric system works in real life:

Ages 4-6: If you have a pencil that is 15 centimetres long, that’s the same as 150 millimetres. You can count by tens to see how many millimetres are in a centimetre!

Ages 7-9: If you walk 2 kilometres, that’s the same as 2000 metres. Try walking 1000 metres and then 1000 more – that’s 2000 metres or 2 kilometres!

Ages 10-12: A bottle of water holds 1.5 litres. That’s the same as 1500 millilitres. If you drink 500 millilitres, you’ve had 1/3 of the bottle!

Try it as a mini adventure

Adventure: The Metric Mission

You are a young explorer on a mission to measure everything in the jungle using the metric system!

1. First, you measure a tree and find it is 3 metres tall.
2. Then you find a leaf that is 5 centimetres wide.
3. You drink 250 millilitres of water from a stream.
4. Finally, you collect a rock that weighs 500 grams.

Now, convert everything to the next bigger unit:

• How tall is the tree in metres?
• How wide is the leaf in centimetres?
• How much water did you drink in litres?
• How much does the rock weigh in kilograms?

Common mistakes

• Mistake: Thinking that 100 centimetres = 1 kilometre.
• Why it happens: Confusing the order of units or forgetting that 100 cm = 1 m and 1000 m = 1 km.
• Fix: Remember that 100 cm = 1 m and 1000 m = 1 km. So 1000 m = 1 km, not 100 cm = 1 km.

• Mistake: Mixing up milligrams and millilitres.
• Why it happens: Both end in "milli", so it’s easy to confuse them.
• Fix: Remember that milligrams measure weight, and millilitres measure capacity.

• Mistake: Forgetting that 1000 ml = 1 l.
• Why it happens: Not seeing the pattern of 10s.
• Fix: Count by 1000s: 1000 ml = 1 l, 2000 ml = 2 l, etc.

Parent and carer guide

Help your child understand the metric system by:

1. Using everyday objects to show how units relate. For example, a 10-centimetre ruler shows how 10 cm = 1 dm (decimetre).
2. Playing games like "Metric Match", where you say a measurement and they find an object that matches it.
3. Using a kitchen scale to show how 1000 grams = 1 kilogram.
4. Walking together and counting how many metres you walk to make 1 kilometre.
5. Encouraging them to write down their measurements and convert them to other units.

Don’t worry if they get confused at first. The metric system takes time to understand, and practice makes progress!

Practice questions

1. How many millimetres are in 1 centimetre?
2. How many centimetres are in 1 metre?
3. How many metres are in 1 kilometre?
4. How many millilitres are in 1 litre?
5. How many grams are in 1 kilogram?
6. Convert 5000 metres to kilometres.
7. Convert 3000 millilitres to litres.
8. Convert 7000 grams to kilograms.
9. Convert 800 centimetres to metres.
10. Convert 2500 milligrams to grams.

Answers:

1. 10 mm
2. 100 cm
3. 1000 m
4. 1000 ml
5. 1000 g
6. 5 km
7. 3 l
8. 7 kg
9. 8 m
10. 2.5 g

FAQ

What is the metric system?

The metric system is a way of measuring things using numbers based on 10. It helps us measure length, weight, and capacity.

Why do we use the metric system?

It’s easier to use because it uses simple numbers like 10, 100, 1000. It’s used all over the world, so it helps people from different countries understand each other.

How does the metric system help in science?

Scientists use the metric system to make sure their measurements are the same and can be shared with others. It makes experiments and data easier to understand.

How can I practice the metric system at home?

You can measure your height, the weight of your toys, or how much water you drink. Try converting between units like centimetres and metres or grams and kilograms.

What are some real-life uses of the metric system?

You use it when cooking, measuring your garden, walking, buying milk, or even playing sports. It helps you know how far you run or how much you weigh.