Mass and Weight Comparisons

Overview

In this lesson you will explore mass using simple scales and compare the “heaviness” of everyday objects such as apples and oranges. Students will measure, record, and communicate how objects compare by using appropriate measurement language.

Learning intentions

Students will be able to:

• identify that mass is how much matter an object has (often felt as heaviness)
• measure and compare masses of familiar items using a balance scale
• use measurement words such as heavier, lighter, equal, mass
• record findings in simple ways (oral, drawings, tally, or number sentence)

Success criteria

• I can place objects on a balance and observe which side is heavier or lighter.
• I can measure mass using a scale and record the numbers (or simple equal/non-equal statements).
• I can compare two objects and explain my thinking using correct language.

Curriculum links

• Measuring and using everyday units for mass (estimating, measuring, and comparing)
• Using appropriate measurement tools and sharing methods
• Collecting and recording data from observations and measurements to answer questions
• Developing mathematical language for comparison and measurement

Lesson structure (45 minutes)

1. 5 min – Starter: Feel and predict

• Show two items (for example, an apple and an orange) without revealing which is heavier. Students handle them briefly and predict which is heavier.
• Ask: “What makes something feel heavier? Do you think it’s the same for all items?”

2. 8 min – Mini-lesson: What scales show

• Introduce the balance scale and explain that it helps us compare mass by balancing.
• Demonstrate three outcomes: one side balances (equal), one side is down (heavier), and swap objects to confirm.
• Emphasise vocabulary: heavier, lighter, equal, mass.

3. 12 min – Hands-on measuring in pairs

• In pairs, each pair measures the mass of at least two object pairs (for example: apple vs. orange, toy block vs. eraser, two types of fruit).
• Students place objects on the pans, wait for the balance to settle, then record the result.
• Teacher circulates, prompting students to explain: “Which is heavier and how do you know?”

4. 10 min – Measuring with consistent units

• Model measuring an object using a simple unit (e.g., gram weights) or a classroom mass guide.
• Students then measure one additional item, ensuring the same unit is used each time.
• Remind: “To compare fairly, we must use the same scale and the same unit.”

5. 7 min – Whole-class share: Comparing and justifying

• Students share one comparison they measured (e.g., “The orange is heavier than the apple” or “They are equal”).
• Teacher asks follow-up questions: “What did the scale show? Did the numbers match your prediction?”

6. 3 min – Exit ticket: Quick record

• Students complete a short response: draw one comparison and write one sentence using heavier/lighter/equal.
• For Year 3 students ready for numbers: include a simple measured value (with teacher support if needed).

Resources

• Balance scales (one per group/pair) and trays/pans
• Measuring masses/weights (gram blocks or standard classroom weights) if available
• Apples and oranges (or other familiar items with clear differences)
• Extra items for comparisons (toy, eraser, small containers, rulers only if needed)
• Recording sheets with prompts (draw the items, circle heavier/lighter/equal, optional number line)
• Student pencils, crayons, and labels for grouping
• Timer for hands-on rounds
• Visual vocabulary cards: heavier, lighter, equal, mass

Assessment

• Observation checklist during pair work: correct use of scale, correct comparison language, willingness to explain.
• Review of recording sheets: ability to match scale outcome to comparison statement.
• Exit ticket: uses at least one accurate comparison sentence and/or measured value.

Differentiation

• Support: Provide sentence starters (“I measured… The… is heavier/lighter than… because…”) and a partially completed recording sheet.
• Support (SEN): Offer a “choose and confirm” routine: predict, measure, then only record the comparison (no unit numbers required).
• Extension: Challenge students to order three objects from lightest to heaviest and explain how they checked.
• EAL: Use real objects, gestures, and vocabulary cards; allow responses as drawings plus one spoken or written key word (heavier/lighter/equal).