Metric and Imperial Conversion

Lesson Overview

Duration: 50 minutes
Number of Students: 20
Level: Functional Skills Maths, Entry Level to Level 1
National Curriculum Links:

Number: use and interpret standard units of measure
Solve problems involving measurement and conversion of units
Understand and use equivalences between metric and imperial units

Relevant National Curriculum references (England KS4 Functional Skills Maths):

NCETM (2019): Solve problems involving conversion between metric units and imperial units (including length, weight and capacity) using a conversion graph or factor
Functional Skills Maths Standard (Level 1): Use standard units of measurement and convert between them, including metric and imperial

Learning Objectives (WALT)

WALT: Convert between metric and imperial units of length, weight, and capacity using conversion factors and conversion graphs.
Understand key conversion factors (e.g., 1 inch = 2.54cm, 1 pound = 0.4536 kg, 1 pint = 0.568 litres).
Read and interpret conversion graphs accurately.
Solve real-life problems involving unit conversions.

Success Criteria

I can recall common metric and imperial units for length, weight, and capacity.
I can use conversion factors correctly to convert units in both directions.
I can accurately read and interpret conversion graphs to solve conversion problems.
I can apply conversions to solve word problems independently.

Resources Required

Whiteboard and markers
Printed copies of conversion charts (length, weight, capacity)
Printed conversion graphs (length, weight, capacity)
Calculators (optional for Entry Level, recommended for Level 1)
Worksheets differentiated by ability
Rulers (cm and inches), kitchen scales and measuring jugs for practical demonstration

Lesson Breakdown

1. Introduction & Starter (10 minutes)

Brief class discussion: What units do we use in the UK for length, weight and capacity? Probe for everyday examples (height in feet/inches, food weights in grams/pounds, milk in litres/pints).
Introduce key conversion factors on the board:
- Length: 1 inch = 2.54 cm; 1 foot = 12 inches
- Weight: 1 pound = 0.4536 kg
- Capacity: 1 pint = 0.568 litres
Use a practical demonstration for impact: measure a textbook in cm and inches using rulers; weigh classroom object in kg and pounds; show a pint bottle of water and litres.
WALT and Success Criteria displayed clearly.

2. Direct Teaching and Modelling (10 minutes)

Modelling how to use a conversion factor:
- Convert 20 inches to cm (multiply by 2.54)
- Convert 5 kg to pounds (divide by 0.4536)
Use number line conversion graphs for length: plot inches on one axis and cm on the other; show how to read values and interpolate. Example: find cm equivalent of 15 inches using graph.
Highlight strategies: multiply for one direction, divide for reverse conversion.
Emphasise checking answers for sense (e.g., 1 inch should be about 2.5 cm).

3. Guided Practice (15 minutes)

Task: Students work in pairs rotating between 3 stations:

Station 1: Conversion factor problems using rulers and scales (e.g. convert weights and lengths).
Station 2: Use printed conversion graphs to find equivalent values for length, weight, and capacity.
Station 3: Word problems involving conversions (e.g. “A recipe calls for 500ml milk, how many pints is this?”).

Teacher role: Circulate and support students, prompt with questions like "How do you know whether to multiply or divide?"

4. Independent Work and Extension (10 minutes)

Hand out differentiated worksheets:
- Entry Level: Simple conversions using conversion factors, with prompts.
- Level 1: Mixed conversions including graph reading and multi-step word problems.
Extension for advanced learners: Challenge problems that require converting compound units or using conversion factors backwards, e.g. “If a parcel weighs 3 pounds, how many kilograms? How much heavier is this than a 2 kg parcel?”

5. Plenary and Assessment (5 minutes)

Recap key points: conversion factors and use of graphs. Ask random students to provide examples of conversions they learned.
Mini quiz on board—students convert 1 or 2 examples mentally or on mini whiteboards (e.g. convert 10 inches to cm, 2 pints to litres).
Highlight next steps and where to find help with conversions.

Differentiation Strategies

Use of practical, visual aids (rulers, scales, graphs) to support diverse learning styles.
Paired work to encourage peer support and discussion.
Simplified instructions and step-by-step guided modelling for lower ability learners.
Extension problems and open-ended questions for higher ability learners.
Use of calculators encouraged for those with difficulties in arithmetic.

Assessment and Feedback

Informal formative assessment through observation during guided practice stations.
Peer feedback at paired work stations.
Mini quiz in plenary for quick check of understanding.
Collect independent worksheets for formal assessment and to inform next lessons.

By embedding real-world, hands-on activities paired with graphical and numerical approaches, this lesson ensures Functional Skills learners build confidence and competence in converting between metric and imperial measurements, fully aligned with the National Curriculum for England.