Mass and Capacity Reasoning

Lesson Overview

• Subject: Mathematics
• Year Group: Year 3
• Duration: 60 minutes
• Curriculum Area: White Rose Maths – Year 3, Spring Block 4 (Mass and Capacity – Reasoning Questions)
• Class Size: 30 students
• UK National Curriculum Objective:
  • Compare, measure, and record mass (kg/g) and volume/capacity (l/ml).
  • Solve problems involving these measures, using appropriate reasoning and mathematical vocabulary.

---

Learning Objectives

By the end of the lesson, students will:

1. Apply reasoning skills to solve problems related to mass and capacity.
2. Use comparison language (e.g. heavier, lighter, more, less) to explain answers.
3. Interpret and answer reasoning questions using pictorial representations.
4. Work collaboratively to solve problems with different levels of difficulty.

---

Lesson Breakdown

Starter Activity (10 minutes) – Class Discussion & Warm-Up

• Question: What do we use to measure mass and capacity?
• The teacher demonstrates with real objects:
  • A litre bottle of water
  • A bag of sugar (1kg)
  • A cup of juice (250ml)
  • A balloon partially and fully inflated
• Think-Pair-Share:
  • Students discuss which objects are heavier/lighter, hold more/less liquid.
  • Teacher reinforces vocabulary: heavier, lighter, more, less, equal, approximate, estimate.

---

Main Teaching (15 minutes) – Modelling & Examples

• Teacher models reasoning-based questions on mass and capacity:

  Example 1:
  Two jugs hold different amounts of juice. One jug holds 500ml, the other holds 700ml. Which jug has more juice and by how much?

  Example 2:
  A bag of flour weighs 2kg. A bag of sugar weighs 1kg. How much heavier is the flour?

• Use bar models and comparison scales to support answers.

• Introduce three levels of reasoning questions (mild, spicy, hot) to differentiate learning.

---

Guided Practice (15 minutes) – Differentiated Problem Solving

Students work in small groups, tackling reasoning questions with picture representations.

Mild (Support – Lower Ability)

Use pictures with labelled values. Students match and compare.

![Mild Example]

• A scale with a watermelon (3kg) and a pineapple (2kg). Which is heavier? By how much?
• Two cups of juice: one has 250ml, the other 500ml. Which one has more?

Spicy (Expected – Middle Ability)

Students solve word problems using bar models or comparison scales.

![Spicy Example]

• A cat weighs 4kg, a dog weighs 9kg. How much heavier is the dog?
• Two jugs hold 1.5 litres and 750ml. How much less liquid is in the smaller jug?

Hot (Challenge – Higher Ability)

Students solve multi-step reasoning problems and justify answers.

![Hot Example]

• A chocolate cake weighs 3kg. Two cupcakes weigh 1.2kg in total. How much heavier is the cake?
• A bucket has 5 litres of water. 2.3 litres is poured out. How much water is left?

---

Independent Work (12 minutes) – Problem Solving & Reasoning

• Students independently work on differentiated problem-solving sheets.
• They must explain their answers using sentences.
• Example sentence starters:
  • I know this because…
  • I compared… and found…
  • This is heavier because…

The teacher circulates, providing targeted support.

---

Plenary (8 minutes) – Reflection & Mini Quiz

• Quickfire whiteboard quiz:

  • The teacher displays pictures of objects with different weights/capacities.
  • Students hold up answers on mini whiteboards.

• Reflection Question:

  • When have you used mass and capacity in real life?
  • Students share answers (e.g. baking, shopping, pouring drinks).

• Extension Question:

  • If a bottle holds 600ml and you drink half, how much is left?

---

Assessment for Learning (AfL) Strategies

✅ Observation – Teacher monitors accuracy of verbal and written answers.
✅ Targeted questioning – Ensuring students explain reasoning.
✅ Self-reflection – Students justify their reasoning.
✅ Whiteboard quiz responses – Checking understanding at the end.

---

Resources Needed

✔ Real-life objects (bottles, jugs, food items)
✔ Mini whiteboards and markers
✔ Printed problem-solving sheets (Mild, Spicy, Hot)
✔ Visual pictorial representations (scales, bar models)

---

Teacher’s Reflection Post-Lesson

📌 What went well?
📌 Which students needed extra support?
📌 Were students able to justify their reasoning?

---

This lesson plan excites students with real-world applications and reasoning challenges, making maths engaging and practical! 🚀