Exploring Capacity

Overview

Lesson 1 of 6 in Capacity and Volume: Measuring in Litres. Students investigate capacity as how much a container can hold and volume as the amount of space inside it, using estimation, comparison and whole-litre measurement.

Learning intentions

• WALT explain capacity and volume in our own words.
• WALT estimate and compare the capacity of containers.
• WALT measure capacity using a labelled tool and whole litres.
• WALT use mathematical language to explain our thinking.

Success criteria

• I can explain capacity and volume in my own words.
• I can make a sensible estimate and explain why.
• I can compare containers using more, less, equal, full and empty.
• I can measure capacity in whole litres with help.

Curriculum links

• Measurement: estimate and measure capacity using labelled tools and whole-number units.
• Measurement: compare and order objects by capacity.
• Mathematical thinking: notice, explore, test and explain ideas using measurement.
• Communicating mathematically: use appropriate measurement vocabulary, diagrams and recorded results.

Lesson structure (60 minutes)

1. 0–10 min – Notice and wonder warm-up Open with the hook and learning intention slides. Show a tiny cup, a 1 L jug and a large bowl. Ask, “Which holds the most? How could we find out?” Students silently order the containers, then justify their ideas to a partner. Introduce the words capacity, volume, container, litre (L) and estimate. Clarify that capacity is how much a container can hold, while volume is the amount of space inside it.

2. 10–15 min – Model estimating and measuring Use the 1 L jug to model an estimate before measuring. Think aloud: “The bowl looks as if it may hold about three litres because it is wide and deep.” Demonstrate filling carefully, counting each litre once and recording the result. Discuss why height alone is not enough: a tall, narrow container may hold less than a short, wide one. Refer to the vocabulary and measuring demonstration slides.

3. 15–40 min – Mystery containers investigation Organise students into groups of four or five. Give each group several covered or labelled containers, a 1 L measuring jug, a tray and water. Distribute the capacity investigation recording sheet and, where useful, the results table templates for groups needing a larger shared recording space. Students predict which container holds the most, order the containers, then check by filling with whole litres and counting carefully. Use small amounts and partly fill larger containers if needed. Students record the estimate, actual result and comparison words. Year 3 support: provide picture vocabulary cards and the sentence frame, “I think ___ holds more because ___.” Adults prompt students to keep track of each litre. Year 4 extension: include a container holding 1 L 500 mL. Discuss why this is more than 1 L but less than 2 L, while keeping the main recording in whole litres.

4. 40–55 min – Capacity sort and compare Groups receive six dry containers and order them from least to greatest capacity without measuring first. They then check at least three using the labelled jug. Ask: “What makes an estimate sensible? Can a taller container hold less? How do we know which container has greater capacity? Is capacity the same as height?” Invite groups to explain one estimate that changed after testing. Use the investigation discussion and comparison prompt slides to guide sharing.

5. 55–58 min – Class consolidation Return to the opening containers. Revisit the original predictions and ask students to complete the statements orally: “Capacity tells us…” and “Volume is…” Record a class definition using student language. Emphasise that full and empty describe how much is currently in a container, while capacity describes how much it can hold.

6. 58–60 min – Exit ticket and clean-up check Students complete the exit task on the final draw-and-explain exit ticket: draw two containers, circle the one with greater capacity and complete, “Capacity means ___.” Collect responses for next-lesson grouping. Before leaving, groups return equipment, empty water safely and wash hands.

Resources

• the capacity introduction and activity deck
• the capacity investigation and exit ticket
• the results table templates
• Assorted clean containers of different shapes and sizes
• 1 L measuring jugs
• Water, trays and towels
• Pencils and group recording materials
• Picture vocabulary cards and sentence frames
• Labels or covers for mystery containers

Assessment

• Listen for accurate use of capacity, volume, litre, more, less and equal during partner and group talk.
• Check whether students make a reasoned estimate, count each litre once and record measurements accurately.
• Use exit tickets to identify who can distinguish capacity from height and explain the idea in their own words.

Differentiation

• Support students with a small number of clearly different containers, picture vocabulary cards, sentence frames and adult modelling of one-litre counting.
• Pair students strategically and assign roles such as estimator, pourer, counter, recorder and reporter.
• For EAL and students needing additional support, demonstrate each word with a real object, gesture and labelled visual; accept oral explanations or drawings.
• Extend Year 4 students by comparing 1 L, 1 L 500 mL and 2 L, and asking them to explain why shape and height do not determine capacity by themselves.