Model making and scale

Quick answer

Model making and scale help us create smaller versions of real things using a special ratio. If you make a model car that is 1/10th the size of a real car, the scale is 1:10. This means every 1 unit on the model equals 10 units on the real car.

Learning outcome

By the end of this page, you will understand how to use scale factors to make smaller versions of real objects, and you will be able to calculate the real size of objects from their model size.

• You can explain what scale means in simple words
• You can find the real size of an object when you know its model size and the scale
• You can make a simple model using a given scale
• You can compare different scales and say which one makes things smaller or bigger

Why this matters

Scale is used everywhere in the world! Builders use scale to make plans for big buildings. Car designers make tiny models before making the real car. Even your toys use scale! When you play with a toy train or a model airplane, you're using scale. Understanding scale helps you think about size, space, and how things fit together. It's useful for science, art, games, and even cooking!

How it works

Scale is a way to show how much smaller or bigger something is compared to the real thing.

1. First, we choose a scale factor, like 1:10 or 1:50
2. Then, we use that ratio to make the model smaller
3. If the scale is 1:10, then 1 unit on the model equals 10 units on the real object
4. So if the real car is 500 cm long, the model is 500 ÷ 10 = 50 cm long
5. Conversely, if the model is 50 cm long and the scale is 1:10, the real car is 50 × 10 = 500 cm long

Examples you can see

Let's imagine you're making a model of a house. You decide the scale is 1:50. This means 1 cm on your model house equals 50 cm on the real house.

Real-world example: Imagine you're planning a garden. You want to put a small fountain in the middle. Your garden is 10 metres long and 8 metres wide. You decide to make a model using a scale of 1:100. That means 1 cm on your paper model equals 100 cm (or 1 metre) in your real garden.

So your model garden will be:

• 10 metres ÷ 100 = 0.1 metres = 10 cm long
• 8 metres ÷ 100 = 0.08 metres = 8 cm wide

Try it as a mini adventure

Adventure: Build Your Own Model Boat!

You are a young architect designing a model ship for a school project. You have a real ship that is 120 metres long. You want to make a model that is 1:20 scale.

1. First, you need to know how long your model should be.
2. Real ship = 120 metres
3. Scale = 1:20
4. Model length = 120 ÷ 20 = ? metres
5. Model length = ? cm
6. Now you can draw your model!

Next, you decide to make a second model of a different ship. This one is 80 metres long, and you want it to be 1:10 scale.

1. Real ship = 80 metres
2. Scale = 1:10
3. Model length = 80 ÷ 10 = ? metres
4. Model length = ? cm

Which model will be bigger? Why?

Common mistakes

• Mistake: Thinking that 1:50 means the model is 50 times smaller. Why: Children often confuse the ratio. 1:50 means 1 unit on the model = 50 units on the real object. Fix: Always remember that the first number is the model, the second number is the real thing.
• Mistake: Forgetting to convert units when working with scales. Why: If you have a scale of 1:100, and your real car is 5 metres long, it's easy to forget that 5 metres = 500 cm. Fix: Convert everything to the same unit before calculating.
• Mistake: Adding the numbers in the ratio instead of multiplying or dividing. Why: Some children think 1:10 means 1 + 10 = 11, and then they use 11 in calculations. Fix: Remember that ratios show a relationship, not a total. 1:10 means 1 part model to 10 parts real.
• Mistake: Confusing the direction of scale. Why: If you know the model size and the scale, it's easy to forget whether to multiply or divide. Fix: If you're finding real size from model size, multiply. If you're finding model size from real size, divide.

Parent and carer guide

Help your child understand scale by using everyday examples:

• Look at maps with scales like 1:50,000. Ask how far 1 cm on the map represents in real life.
• Build a small model house using blocks or cardboard. Use a 1:10 scale.
• Use a toy car to show how a real car is 10 times bigger.
• When cooking, use a 1:2 scale to make a smaller batch of soup or cake.
• Play with model trains or cars and discuss their scales.

Encourage your child to ask questions like:

• Why do we use scales?
• What happens if I change the scale?
• How do I know which number is the model and which is the real thing?

Don't worry if your child makes mistakes. These are normal learning steps. Ask questions that help them think, not just give answers.

Practice questions

1. A model car is made at a scale of 1:20. If the model is 15 cm long, how long is the real car?
2. A model house is 12 cm wide. The scale is 1:50. How wide is the real house?
3. A real bridge is 100 metres long. If the model is 5 cm long, what is the scale?
4. If a real elephant is 4 metres tall and the model is 20 cm tall, what is the scale?
5. A model of a football pitch is 10 cm wide. The scale is 1:100. How wide is the real pitch?

Answers:

1. 15 cm × 20 = 300 cm = 3 metres
2. 12 cm × 50 = 600 cm = 6 metres
3. 100 metres = 10,000 cm. 10,000 ÷ 5 = 2,000. Scale is 1:2000
4. 4 metres = 400 cm. 400 ÷ 20 = 20. Scale is 1:20
5. 10 cm × 100 = 1,000 cm = 10 metres

FAQ

What is scale in maths?

Scale is a ratio that compares the size of a model or drawing to the size of the real object. For example, a scale of 1:10 means 1 unit on the model equals 10 units on the real object.

How do I work out the real size of something from a model?

Multiply the model size by the scale factor. For example, if a model car is 10 cm long and the scale is 1:50, the real car is 10 × 50 = 500 cm long.

Can I make a model that is bigger than the real object?

Yes! If the scale is 2:1, the model is twice as big as the real object. This is called an enlargement.

Why do we use scales?

Scales help us plan, design, and understand big things in small spaces. They're used in maps, building plans, toy models, and scientific drawings.

What does 1:50 scale mean?

It means that 1 unit on the model equals 50 units on the real object. So if your model is 1 cm, the real object is 50 cm.