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Why do designers build models and prototypes, and how do different kinds of model serve different purposes?

Use models and prototypes, from quick study models to working prototypes, to test ideas in three dimensions and gather evidence for refinement

A focused answer to the O-Level Design and Technology outcome on modelling. Study models, mock-ups and working prototypes, the materials used, and how models test ideas and gather evidence.

Generated by Claude Opus 4.87 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this dot point is asking
  2. The answer
  3. Examples in context
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What this dot point is asking

SEAB wants you to use models and prototypes to test ideas in three dimensions and gather evidence to refine a design. You should know the difference between a quick study model and a working prototype, understand which materials suit each, and explain why modelling before making the final product saves time and money and produces a better design. Modelling is central to the Design Project.

The answer

Why model at all

A flat sketch can only show so much. Many problems, with fit, proportion, function and feel, appear only in three dimensions. Modelling turns an idea into something you can hold, look at from all sides, and test. It reveals faults early, when they are cheap to fix, and gathers real evidence to refine the design. Designers model because it is far cheaper to discover a problem in a card model than in a finished product.

Types of model and prototype

Models range from rough to refined:

  • Study (or development) models. Quick, simple models, often in card, foam or clay, used to test shape, size and proportion. They do not need to work. Their job is to make a form real enough to judge.
  • Mock-ups. More resolved models that show appearance and layout, useful for checking how a product looks and how controls are arranged.
  • Working prototypes. Functioning versions made in materials closer to the final product, used to test whether the design actually works in use. A working prototype is what you test against the full specification.

Each kind suits a different question: study models answer "is the shape and size right?"; working prototypes answer "does it work?".

Choosing modelling materials

Early models use cheap, easy-to-work materials such as card, foam board, modelling foam and clay, because they are quick to cut, shape and change. This suits the early aim of trying many versions fast, and it encourages experimentation, because nobody minds altering or discarding a card model. As the design firms up, prototypes move to materials closer to the final ones (woods, plastics, metals) to test real function and strength.

Using models to gather evidence

A model is only useful if it informs the design. The designer tests the model (does the phone fit the slot? does the handle feel comfortable? does the stand tip?), records what is found, and uses the evidence to refine the design. This links modelling to the iterative loop: model, test, learn, change. In the Design Journal, photographs of models with notes on what each test revealed are strong evidence of real development.

Examples in context

Example 1. A card model of a chair. Before cutting any timber, a designer builds a full-size card-and-tape model of a chair to check seat height, backrest angle and stability with a real person sitting in it. The model shows the seat is too high, fixed in minutes by trimming the card legs. Catching the ergonomic fault in card saves wasting expensive timber on a chair that would not have fitted users.

Example 2. A working prototype of a torch. A foam study model first fixes the size and grip shape. A working prototype with a real switch, battery and bulb then tests whether the torch is bright enough, the switch is easy to find, and the case holds together. The functioning prototype reveals the switch is hard to find in the dark, a fault only a working model could expose, leading to a raised, textured switch.

Try this

  • Cue. State the purpose of a study model. Answer: to test shape, size and proportion of an idea quickly in three dimensions; it does not need to function.

  • Cue. Give two materials suitable for quick early models and say why. Answer: card and foam board (or modelling foam/clay) because they are cheap, quick and easy to cut, shape and change.

  • Cue. Explain what a working prototype tests that a study model cannot. Answer: whether the design actually functions in use, tested against the specification, because it is made to work in near-final materials.

Exam-style practice questions

Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Original6 marksA designer is developing a handheld garden tool. (a) Explain the difference between a study model and a working prototype. (b) Give two reasons why the designer should make models before producing the final product.
Show worked answer →

(a) A study model is a simple, quick model (often in card or foam) used to test shape, size and proportion; it does not need to work. A working prototype is a more finished, functioning version made in materials closer to the final product, used to test whether the design actually works in use.

(b) Two reasons: modelling tests an idea in three dimensions, revealing problems with fit, size or function that flat sketches hide; and it lets the designer gather evidence to refine the design and fix faults cheaply before committing to the final, more expensive product.

What markers reward: study model as a quick form/size test versus working prototype as a functioning, near-final test, and two genuine reasons (test in 3D, catch problems early, gather evidence to refine, save cost) rather than one reason stated twice.

Original4 marksExplain why a designer might use cheap materials such as card and foam for early models rather than the final material.
Show worked answer →

Cheap materials such as card and foam are quick, easy and inexpensive to cut, shape and join, so the designer can make and change models rapidly. Early in development the aim is to test shape, size and proportion and to try many versions, not to make a finished object, so using the final material would waste time, money and material on something that will be changed.

Using cheap materials also encourages experimentation: the designer is willing to alter or discard a card model, whereas an expensive model feels too precious to change. This keeps development fast and iterative, with faults found and fixed cheaply.

What markers reward: cheap materials being quick, easy and inexpensive to work, suiting the early aim of testing form and trying many versions, and the point that low cost encourages free experimentation and keeps iteration cheap.

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