Users, Needs and Constraints

Overview

In this third theory lesson of Design, Model and Make, students investigate how users, purpose, materials, sustainability, safety, cost and manufacturing methods influence design decisions. They apply this analysis to their own product concept and develop measurable success criteria to guide later modelling, making and evaluation.

Learning intentions

Students will:

• analyse the needs of a target user and the purpose of a proposed product
• explain how material properties, sustainability, safety, cost and manufacturing methods affect design decisions
• develop measurable design criteria for their own product
• justify design decisions using appropriate technical language

Success criteria

• I can identify a specific user, need and purpose for my product.
• I can explain how at least four constraints influence my design.
• I can write success criteria that are specific, measurable and relevant.
• I can justify a material or manufacturing choice using evidence.

Curriculum links

• Analyse needs and opportunities, develop design briefs, and investigate and select materials, tools and processes for designed solutions.
• Analyse how material properties, systems, components, tools and equipment can be combined to create a designed solution.
• Develop independent design criteria, including sustainability, to evaluate design ideas and solutions.
• Apply innovation skills to generate, test, iterate and communicate design ideas and decisions.
• Consider ethical, safety and sustainability factors in design and technologies occupations.

Lesson structure (60 minutes)

1. 0–5 min · Hook and retrieval. Teacher displays two contrasting product images, such as a mass-produced jewellery item and a customised accessible product, using the opening comparison slide, and asks, “Which product is better designed, and for whom?” Students discuss with a partner, then recall one design decision from the previous lesson that could affect a product’s success.

2. 5–15 min · Direct teaching: the design decision web. Teacher uses the design decision slides to explain how user needs, purpose, aesthetics, function, materials, sustainability, safety, cost and manufacturing methods interact. Model the example of a reusable school lunch container: the user needs easy opening, the purpose is safe food storage, and material choice affects durability, cleaning, cost and end-of-life disposal. Students annotate the example and contribute one possible trade-off, such as low cost versus long life.

3. 15–25 min · Product analysis. Teacher places several familiar products or product photographs around the room and provides the product analysis and criteria worksheet. Students work in pairs to analyse one product, identifying its target user, purpose, materials, likely manufacturing method, safety considerations, sustainability issues and approximate cost. Pairs record one strength, one constraint and one improvement. Teacher circulates, questioning: “What evidence suggests this material is suitable?” and “Who might be excluded by this design?”

4. 25–35 min · Share and prioritise constraints. Teacher invites pairs to share findings and records recurring constraints on the board, revisiting the constraints discussion slides. Students individually rank the three most important constraints for their own planned product, then explain one ranking to a partner. Emphasise that constraints are not simply problems; they help designers make purposeful decisions. Connect discussion to the class values of Respect for users and communities, Integrity in sustainable and safe choices, and Excellence in function and finish.

5. 35–52 min · Develop measurable success criteria. Teacher models changing vague statements into measurable criteria: “It must be strong” becomes “It must support 500 g for 30 seconds without permanent deformation”; “It should be sustainable” becomes “It should use predominantly recycled, renewable or reusable materials and minimise material waste.” Students complete the criteria section of the product analysis and criteria worksheet for their own product. They write at least six criteria covering function, user needs, materials or properties, safety, sustainability, cost and manufacture. At least four must be measurable using a number, test, scale or observable condition.

6. 52–60 min · Peer check and exit reflection. Students swap worksheets with a partner and use the peer-check and plenary slides to test whether each criterion is clear, measurable, realistic and linked to the user. Partners suggest one improvement, not a redesign. Students complete the final reflection on the product analysis and criteria worksheet: “My most important constraint is…”, “I will test this criterion by…”, and “One decision I can justify is…”. Teacher collects worksheets to inform the next practical modelling lesson.

Resources

• the Users, Needs and Constraints slide deck
• the product analysis and criteria worksheet
• Sample products or printed product photographs, including jewellery, textiles or CAD-designed objects
• Whiteboard and markers
• Student design briefs or product concepts from the previous lesson
• Rulers, scales or other simple measuring tools for discussing measurable criteria
• Projector or interactive display
• Sticky notes or highlighters

Assessment

• During discussion, check whether students can distinguish user need, purpose and design constraint, and use their explanations to address misconceptions.
• Review pair product analyses for evidence-based comments about materials, sustainability, safety, cost and manufacturing.
• Collect the completed worksheets and assess whether each student has written relevant, measurable criteria and a method for testing at least one criterion.

Differentiation

• Provide a word bank and sentence starters such as “The user needs…”, “This material is suitable because…”, and “The product will be successful if…”.
• Offer a partially completed product analysis for students requiring support, and allow oral rehearsal before written responses.
• Use photographs and real products to support students with EAL/D needs; explicitly teach terms such as constraint, durability, life cycle, manufacture and measurable.
• Challenge confident students to identify competing variables, such as cost versus durability, and propose a testing method that produces reliable evidence.
• Accept typed, handwritten, diagrammatic or speech-to-text responses where appropriate, while maintaining the same design expectations.