Capacity Experiments

Overview

In this lesson (Lesson 5 of 7), students explore capacity using everyday containers and simple water-filling experiments. They compare containers using liters and milliliters and practise choosing appropriate units.

Learning intentions

• Students will measure and compare the capacity of containers using liters and milliliters.
• Students will estimate first, then measure by filling carefully and recording amounts.
• Students will explain which unit (liters or milliliters) best describes each container.
• Students will use clear language such as “more than”, “less than”, and “about”.

Success criteria

• I can estimate which container holds more before measuring.
• I can measure capacity by filling containers accurately and reading the markings.
• I can record measurements using liters and milliliters (and convert when needed).
• I can compare capacities and explain my thinking using mathematical language.

Curriculum links

• Measures using litres and millilitres to determine and compare capacities.
• Selecting and using appropriate units and doing simple conversions within metric measurement.
• Using measurement data to answer questions and communicate results.
• Developing mathematical reasoning through estimating, testing, and justifying comparisons.

Lesson structure (45 minutes)

1. 5 min – Launch and safety Show 3–4 containers (cup, bottle, jug, measuring jug if available). Briefly revisit safety: carry carefully, wipe spills, and keep water away from notebooks. Students predict which will hold the most and why.

2. 6 min – Whole-class demonstration (estimate then measure) Model an experiment with a clear container and a measuring jug. Ask students to estimate (e.g., “about 500 mL” or “about 1 L”), then fill step-by-step. Emphasise reading the scale at eye level and stopping at the meniscus/line.

3. 18 min – Small-group experiments (hands-on measuring) In groups, students rotate through two measurement tasks:

• Task A: Measure capacity for two everyday containers. Record each amount in mL or L.
• Task B: Find “How much more?” by measuring how much water is needed to fill the smaller container to match the larger one, recording the difference in mL. Teacher circulates with guiding questions: “Which unit are you using and why?”, “What does the scale say?”, “Is your reading closer to 300 mL or 400 mL?”

4. 7 min – Compare and discuss findings Bring the class together. Select 2–3 students to share a comparison (e.g., “The bottle holds more than the cup by 250 mL”). Use a class chart: Container → Estimated → Measured → Compared.

5. 6 min – Quick conversion challenge Use an on-the-spot scenario with measured values, such as “750 mL is how many liters?” and “1 L is how many mL?” Students answer using think-pair-share and then confirm as a class. Focus on the relationship between liters and millilitres (1000 mL = 1 L).

6. 3 min – Exit ticket reflection Students complete a short prompt: “My container holds ___ mL (or ___ L). I estimated ___, so my estimate was (close/not close) because ___.”

Resources

• Assorted everyday containers (cups, small bottles, yoghurt tubs with lids removed, jugs, and one or two measuring jugs)
• Measuring jugs or cups with clear graduations (mL and/or L)
• Water in a large container or jug (teacher-managed pour supply)
• Measuring trays or waterproof mats to reduce mess
• Student recording sheets with columns: Estimate, Measured, Unit, Difference/Comparison
• Paper towels and small buckets/sponges
• Clipboards or clip folders (optional) to write neatly during activities
• Timers for rotation (teacher or screen-based)
• Visual number line or conversion card showing 1000 mL = 1 L

Assessment

• Observation checklist during experiments: correct reading of markings, appropriate unit choice, and accurate recording.
• Review of recorded measurements and comparisons on the class chart.
• Exit ticket: use of liters/millilitres and brief justification of estimation accuracy.

Differentiation

• Support: Provide a “unit choice” prompt card (When the container is bigger, use liters; when it’s smaller, use millilitres). Offer partially completed recording sheets with sentence starters: “I measured ___ mL because…”.
• Support: Pre-teach how to read markings at eye level and how to stop filling precisely.
• Extension: Challenge students to measure three containers and order them from smallest to largest, including the difference between the first and last.
• EAL/SEN: Use consistent language stems (“holds more/holds less”, “about”, “just under”, “just over”) and offer visual supports (container photos, unit conversion card). Allow oral responses alongside written measurements.