Constraints Are Not Criteria

Lab Brief #2

🎯 Your mission

Learn the rule. Then catch nature using it.

⚡ The twist

Constraints make you more creative, not less.

What you'll learn

Criteria are what a design should maximise; constraints are limits it must not cross. A bridge that carries more load is better, but one that is over budget or wider than the gap it must span is simply disqualified, however well it scores elsewhere. Writing the two lists separately before any building starts is what stops a team quietly trading away a constraint to win on a criterion — the commonest route by which a good-looking design becomes an unusable one.

Key words

criterion
A measure a design should maximise, on which more is better.
constraint
A hard limit a design must not cross, regardless of how well it scores on any criterion.

Make a hypothesis first

Before you test: how many tries until it works?

Say your guess out loud — then find out if you were right.

Step 1 of 4 · Read

Think about what you just learned: say what "criterion" and "constraint" mean in your own words before you start.

Step 2 of 4 · Do

Take a design brief for a school water butt and sort fourteen statements into criteria and constraints, justifying each placement in a sentence. Then find the two statements teams most often misfile and explain what going wrong would cost.

Step 3 of 4 · Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 of 4 · Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Question 1 of 3

A budget limit in a design brief is best classified as a:

How sure are you?😐 maybe

Question 2 of 3

A criterion differs from a constraint because a criterion:

How sure are you?😐 maybe

Question 3 of 3

Trading away a constraint to score better on a criterion produces a design that is:

How sure are you?😐 maybe

Mind = blown

🌉 The Eiffel Tower can grow 6 inches taller in summer because metal expands when hot.

Nice work!

You got 0 of 3 right.

Next: Weighting a Decision So the Judgement Is Visible All lessons

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✨ More to explore

🌍 Where you see this in real life: Every bridge, building, and gadget you've ever used started with this.

🏆 Stretch challenge (try it this week): Find something that's broken at home and try to figure out *why* it broke.

👨‍👩‍👧 For the dinner table: “What's something around the house you'd redesign — and how?”

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