Overview

Duration: 45 minutes
Class size: 11 students
Unit: Measuring Mass with Cubes (Lesson 2 of 5)
Age group: Year 1 (ages 5-6)
National Curriculum links:

• Mathematics - Measurement:
  • Year 1 Programme of Study
  • “Compare, describe and solve practical problems for mass/weight”
  • Understand the concept of mass and measure using non-standard units (NC Ref: Y1 Measurement - Mass and Weight)

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Learning Objectives

By the end of the lesson, pupils will be able to:

1. Understand that mass is a measure of how heavy an object is.
2. Use cubes as non-standard units to measure the mass of different objects.
3. Compare the mass of two objects using a balance scale, explaining which is heavier or lighter.
4. Record findings using simple comparative language (heavier, lighter, equal).

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Curriculum Link

Mathematics — Measurement

• Year 1: Pupils should be taught to measure and begin to compare mass/weight using appropriate non-standard units and simple measuring equipment such as balance scales (National Curriculum for England, Key Stage 1).
• Focus on developing the concept of mass through practical investigation.

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Resources

• Balance scales suitable for year 1 pupils (at least 3 sets for group work)
• Plastic cubes (uniform size and weight; approximately 50 cubes for the class)
• A variety of classroom objects of different mass (e.g., small toy car, pencil, eraser, small book, block of wood)
• Recording sheets with pictures of balance scales and simple comparison prompts
• Whiteboard and pen
• Visual cue cards with vocabulary: heavier, lighter, equal

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Lesson Structure

1. Introduction (7 minutes)

• Engagement starter:
  Teacher holds two objects: “Which one do you think is heavier? How can we find out?”
• Ask pupils what they already know about heavy and light objects.
• Introduce the balance scale and explain how it works—when it tips, the heavier side has more mass.
• Show cubes: “Today we are going to measure how heavy things are by using cubes!”
• Recap vocabulary: heavier, lighter, equal.

National Curriculum skill focus: Develop understanding through practical questions and vocabulary.

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2. Main Activity: Measuring Mass with Cubes (25 minutes)

Step 1: Model measuring with cubes (5 minutes)

• Teacher demonstrates placing an object on one side of the balance.
• Shows adding cubes one by one to the other side until the scale balances.
• Counts cubes aloud together to emphasise number of cubes representing mass.

Step 2: Guided practice in pairs/groups (15 minutes)

• Pupils work in pairs, sharing one balance scale and cubes.
• Each pair selects 2 different objects from a ‘mass basket’.
• They predict which object is heavier, then measure using cubes and balance scales.
• Pupils count cubes needed to balance each object and compare.
• Teacher circulates, asking: “Which object has more cubes? What does this tell us?”

Step 3: Record and discuss findings (5 minutes)

• Pupils draw simple pictures of their balance with cubes on recording sheets.
• Write or verbalise “Object X is heavier/lighter/equal to Object Y”.
• Share a couple of examples with the whole class.

National Curriculum skill focus: Practical measuring and comparing, use of non-standard units, language development (heavier, lighter).

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3. Plenary (8 minutes)

• Use a whole-class balance scale demonstration with two objects.
• Invite volunteers to predict, measure, and explain results using cubes.
• Recap key vocabulary with interactive flashcards (e.g., pupils hold cards when teacher says “heavier”).
• Ask reflective questions:
  • “Can we always use cubes to measure weight of everything?”
  • “Why do we add cubes one by one?”
• Highlight real-life uses of weighing (e.g., cooking).
• Praise effort and encourage curiosity for next lesson.

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Assessment

• Formative assessment: Teacher notes during guided practice on pupils’ ability to use scales and count cubes accurately.
• Marking recording sheets: Check understanding of comparison language and correct representation of measurement.
• Oral responses in plenary: Gauge verbal use of vocabulary and reasoning.
• Use observation checklist:
  • Can the pupil balance the scale?
  • Does the pupil use counting to measure?
  • Can the pupil verbally compare masses?

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Differentiation

• Support: Provide visual cue cards for vocabulary, work in smaller groups, prompt counting steps.
• Challenge: Ask pupils to estimate number of cubes before balancing, or measure objects with similar masses to explore subtle differences.

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Extension & Enrichment Ideas

• Create "mass estimations" game: Guess how many cubes before measuring.
• Introduce simple non-standard units like buttons or blocks to compare with cubes.
• Storytime integration: Read a short story about weighing and measurement (e.g., "Goldilocks and the Three Bears" with focus on “just right” weights).

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Teacher’s Notes

• Ensure safety by using lightweight, child-friendly materials.
• Reinforce that cubes are non-standard for mass but help conceptualise weighting.
• Encourage full class participation to build confidence and speaking skills.
• Build excitement by relating the activity to everyday experiences, such as cooking or shopping.

This lesson builds a solid foundation for understanding mass in an accessible, hands-on way that meets the National Curriculum expectations for Year 1.