Mathematics · Year 1 · Measurement and Comparison · Spring Term

Measuring Length with Non-Standard Units

Using everyday objects (e.g., paper clips, blocks) to measure the length of items.

• National Curriculum Attainment Targets
• KS1: Mathematics - Measurement

About This Topic

Mass and weight in Year 1 focus on the concepts of 'heavy' and 'light'. The National Curriculum requires pupils to compare, describe, and solve practical problems for mass or weight (e.g., heavy/light, heavier than, lighter than). Students primarily use balance scales to compare the mass of two objects, moving away from just 'feeling' the weight in their hands, which can be deceptive.

This topic helps children understand that size does not always dictate weight. A large balloon can be lighter than a small stone. By using balance scales, students get a clear visual representation of equality and inequality. This foundational understanding is necessary before they move on to standard units like grams and kilograms. Students grasp this concept faster through structured discussion and peer explanation during hands-on weighing experiments.

Key Questions

1. Explain why using paper clips is a fair way to measure length.
2. Predict what would happen if we used different sized hands to measure the same table.
3. Design a way to measure the length of the classroom using only your feet.

Learning Objectives

• Compare the lengths of two objects using non-standard units.
• Explain the importance of using identical non-standard units for fair measurement.
• Design a method to measure a larger object or space using a chosen non-standard unit.
• Predict the outcome of measuring the same object with non-standard units of different sizes.

Before You Start

Comparing Sizes

Why: Students need to be able to identify and compare objects based on attributes like 'longer' or 'shorter' before they can measure length.

Counting to 20

Why: Accurate measurement relies on counting the number of units used, so a solid understanding of number sequence is necessary.

Key Vocabulary

measure	To find out the size, amount, or degree of something, especially by using instruments or units.
length	The measurement or extent of something from end to end; the greater of two or the greatest of three dimensions of an object.
non-standard unit	A unit of measurement that is not officially recognized, such as a paper clip, block, or hand span.
estimate	To roughly calculate or judge the value, size, amount, or extent of something.

Watch Out for These Misconceptions

Common Misconception

Bigger is always heavier

What to Teach Instead

Children often assume a large box is heavier than a small metal car. Use 'trick' items like a large empty box and a small heavy ball to show that mass depends on the material, not just the size.

Common Misconception

The scale 'goes up' for heavy

What to Teach Instead

Students may think the side that goes up is the heavy one. Use the analogy of a seesaw, the heavy person goes down to the ground, to help them remember that the lower side of the balance scale holds the heavier object.

Active Learning Ideas

Inquiry Circle: Heavy or Light Hunt

Groups are given a 'mystery object' and must find three things in the room that are heavier and three that are lighter, using balance scales to prove their findings to the class.

20 min·Small Groups

Think-Pair-Share: The Size Trap

Show a large sponge and a small lead weight (or heavy stone). Pairs must predict which is heavier, then use the scales to check. They discuss why the 'bigger' item isn't always the 'heavier' one.

10 min·Pairs

Stations Rotation: Weight Matching

Set up stations where students must find how many 'units' (e.g., wooden blocks) it takes to balance a specific toy. They rotate to see how different toys require different amounts of blocks to reach a balance.

20 min·Small Groups

Real-World Connections

• Carpenters use non-standard measurements like their own hand spans or pieces of wood to quickly estimate lengths on a job site before using formal tools.
• Interior designers might use blocks or books to visualize and compare the lengths of furniture pieces within a room layout before committing to specific dimensions.

Assessment Ideas

Quick Check

Provide students with a collection of classroom objects (e.g., pencil, book, glue stick) and a pile of paper clips. Ask them to measure the length of each object using the paper clips and record their findings. Observe if they consistently use the paper clips end-to-end without gaps or overlaps.

Discussion Prompt

Present two scenarios: one where a table is measured with small blocks and another where the same table is measured with large blocks. Ask students: 'Which measurement will have more blocks? Why?' Guide them to explain why using the same size unit is important for fair comparison.

Exit Ticket

Give each student a picture of a classroom object (e.g., a whiteboard). Ask them to draw how they would measure its length using their feet and write one sentence explaining their method. Prompt: 'How many of your feet long is the whiteboard?'

Frequently Asked Questions

What is the difference between mass and weight?

In everyday language, we use them interchangeably. Technically, mass is the amount of 'stuff' in an object, while weight is the pull of gravity on it. For Year 1, we focus on the concept of 'heaviness' and use the term 'mass' as per the National Curriculum.

How can active learning help students understand mass?

Mass is an invisible property until you feel it or use a scale. Active learning strategies, like 'Heavy or Light Hunts', force students to make predictions and then physically test them. Using balance scales in a collaborative setting allows students to see the physical 'tipping point' of equality, which helps them internalize the concepts of 'heavier' and 'lighter' through direct observation.

Why use balance scales instead of digital scales?

Balance scales show the relationship between two objects. Digital scales provide an abstract number, which is harder for a Year 1 child to interpret. Seeing one side go down and the other go up provides a concrete, visual comparison of weight.

How can I teach weight at home?

Use your hands as a 'human scale'. Put an apple in one of your child's hands and a grape in the other. Ask them which 'feels' heavier. Then, use a simple kitchen scale or a homemade coat-hanger balance to check.

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