Science · Unit 15

Engineering and Design

Solving problems by designing and building

Science asks how the world works; engineering asks what can be built with that, under real constraints of cost, materials and time.

The unit covers the design cycle, choosing materials for a job, what makes a structure strong, and testing and improving a design rather than getting it right first time.

This unit breaks down into 22 short steps and 130 questions, starting at difficulty 3 and building to 4. Below you can see exactly what it covers, how the path is structured, and worked examples with explanations.

Steps: 22
Questions: 130
Difficulty: 3-4

What this unit covers

Testing and Improving
Choosing Materials
The Design Process
Strong Structures
Engineering Feats

Where this fits

Draws on Everyday Materials and Forces and Movement.

Where people slip

A failed prototype is a result, not a mistake. The design process assumes failure and is built around learning from it quickly.

How the unit is structured

Engineering and Design runs as 22 short steps that unlock in order. 16 are practice rounds and 6 are challenge rounds that pull together everything before them. Questions start at difficulty 3 and climb to 4 as you progress.

Step 1 · easierStep 22 · harder

Challenge rounds

Example questions

30 real questions from this unit, with the answer and the reason behind it, grouped by what they practise. There are 130 in the unit altogether.

Choosing Materials

Choose all that applyLevel 3
1. Which properties matter most when choosing steel cable for a suspension bridge? Pick all that apply.
- High tensile strengthcorrect
- Resistance to corrosioncorrect
- Reasonable cost for its strengthcorrect
- A bright, shiny color
A bridge cable must be very strong in tension, resist weather corrosion, and be affordable for its strength.
Fill the blankLevel 3
2. Copper is used in electrical wiring because it is an excellent ____ of electricity.
- conductorcorrect
- insulator
- magnet
- resistor
Copper conducts electric current very well, which is why it is used in most wiring.
Match the pairsLevel 3
3. Match each material property to its meaning.
Answer: Strength = Resists breaking under load; Density = Mass packed into a volume; Ductility = Can be drawn into thin wire; Corrosion resistance = Resists rusting
Each property describes a different way a material behaves under use.
Multiple choiceLevel 3
4. Why is aluminum often chosen for aircraft bodies instead of steel?
- It has a high strength-to-weight ratio, so it is light but strong
- It is the cheapest of all metals
- It can never corrode under any conditions
- It cannot conduct electricity at all
Aluminum has a high strength-to-weight ratio, so it stays strong while keeping the plane light.
Fact or fibLevel 4
5. Tensile strength is the maximum stress a material can withstand while being stretched before it breaks.
Answer: True
Tensile strength is exactly the peak pulling stress a material can bear before fracturing.
Guess the numberLevel 4
6. Steel is roughly how many times denser than aluminium?
Answer: 3 times
Steel has a density near 7.8 g/cm3 and aluminium near 2.7 g/cm3, so steel is about three times denser.

Engineering Feats

Fill the blankLevel 3
7. The Golden Gate and Akashi Kaikyo bridges are ____ bridges, hanging their decks from huge main cables.
- suspensioncorrect
- arch
- beam
- truss
Suspension bridges hang the roadway from cables strung between tall towers, allowing very long spans.
Guess the numberLevel 3
8. About how tall is the Burj Khalifa, the world's tallest building?
Answer: 828 meters
The Burj Khalifa in Dubai stands about 828 meters tall.
Match the pairsLevel 3
9. Match each famous structure to what it is.
Answer: Burj Khalifa = World's tallest building; Golden Gate Bridge = Suspension bridge; Hoover Dam = Concrete dam; Channel Tunnel = Undersea rail tunnel
Each is a landmark of engineering built for a different purpose.
Multiple choiceLevel 3
10. The Burj Khalifa uses a Y-shaped 'buttressed core' design mainly to do what?
- Resist wind and sideways forces on a very tall towercorrect
- Lower its construction cost
- Make it look symmetrical only
- Fit in more elevators
The buttressed core braces the tower against wind and sideways forces that grow stronger with height.
Fact or fibLevel 4
11. The Eiffel Tower's open lattice framework lets wind pass through, reducing the wind load it must resist.
Answer: True
Gustave Eiffel's open ironwork was shaped to cut wind resistance, a key reason the tall tower stays stable.
Odd one outLevel 4
12. Which of these famous long-span bridges is NOT a suspension bridge?
- Millau Viaductcorrect
- Golden Gate Bridge
- Brooklyn Bridge
- Akashi Kaikyo Bridge
The Millau Viaduct is a cable-stayed bridge, while the others are classic suspension bridges.

Strong Structures

Choose all that applyLevel 3
13. Which of these help make a tall tower more stable? Pick all that apply.
- A wide basecorrect
- A low center of gravitycorrect
- Triangular bracingcorrect
- Extra mass added at the very top
A wide base, a low center of gravity, and triangular bracing all make a structure harder to tip or twist.
Fact or fibLevel 3
14. A square frame with no diagonal brace can collapse sideways into a parallelogram.
Answer: True
Without a diagonal, a four-sided frame can lean over, which is why bracing is added to make triangles.
Fill the blankLevel 3
15. An arch is strong because it carries its load mainly in ____, pushing the force outward onto its supports.
- compressioncorrect
- tension
- shear
- torsion
Arches turn downward loads into compression along the curve, spreading force to the supports.
Guess the numberLevel 3
16. What is the smallest number of straight sides a polygon can have and still hold its shape as a rigid frame?
Answer: 3 sides
A triangle with three sides is the simplest shape that cannot be deformed without bending its sides.
Match the pairsLevel 3
17. Match each force to what it does to a material.
Answer: Compression = Squeezes or pushes together; Tension = Pulls apart or stretches; Shear = Slides layers in opposite directions; Torsion = Twists the material
Structures must handle several kinds of force, each acting on the material differently.
Multiple choiceLevel 3
18. Which shape is the most rigid and is used in trusses because it will not deform under load?
- Trianglecorrect
- Square
- Rectangle
- Circle
A triangle keeps its shape under force, which is why bridges and towers use triangular bracing.

Testing and Improving

Choose all that applyLevel 3
19. What should engineers do when a prototype fails a test? Pick all that apply.
- Analyze why it failedcorrect
- Redesign the weak partcorrect
- Test the improved versioncorrect
- Ship it unchanged and hope for the best
They analyze the failure, redesign the weak part, and test the new version rather than ignore the result.
Fact or fibLevel 3
20. A factor of safety of 3 means a part is built to handle three times the expected load.
Answer: True
The number tells you how many times the expected load the part can take before failing.
Fill the blankLevel 3
21. Engineers build in a ____ of safety so a structure can carry more than the maximum expected load.
- factorcorrect
- waste
- sketch
- list
A factor of safety gives a margin, so the structure handles surprises without failing.
Multiple choiceLevel 3
22. What is the main reason engineers build a prototype?
- To test the design and find problems before full productioncorrect
- To sell it to customers right away
- To avoid doing any testing
- To make the project look busy
A prototype lets engineers test the design and catch problems before spending on full production.
Put in orderLevel 3
23. Put the test-and-improve cycle in the correct order.
Answer: Build a prototype -> Test it under real conditions -> Find out what failed -> Redesign the weak part -> Test the improved version
Engineers build, test, find the weakness, redesign it, then test again in a loop.
Guess the numberLevel 4
24. A bracket is designed with a factor of safety of 4. If the largest expected load is 500 N, at least how many newtons should the bracket withstand?
Answer: 2000 N
A factor of safety of 4 means the bracket should hold 4 x 500 N, which is 2000 N.

The Design Process

Build the sentenceLevel 3
25. Build a sentence about starting the design process.
Answer: Define the problem before you build
Engineers define the problem clearly before they start building anything.
Choose all that applyLevel 3
26. Which of these are common constraints on an engineering design? Pick all that apply.
- Budget or costcorrect
- Deadline or time availablecorrect
- Available materialscorrect
- The engineer's favorite color
Budget, deadlines, and available materials all limit what a design can be, so they are constraints.
Fact or fibLevel 3
27. In design, a trade-off means improving one feature often costs you something in another.
Answer: True
Trade-offs are common: making a car lighter for speed may make it less crash-resistant, for example.
Fill the blankLevel 3
28. The measurable goals that a successful design must achieve are called design ____.
- criteriacorrect
- constraints
- sketches
- budgets
Criteria are the requirements a solution must meet to count as a success.
Multiple choiceLevel 3
29. In engineering, what is a 'constraint'?
- A limit or restriction on the design, such as budget, size, or materials
- A customer's personal wish about the color
- The final test score of the product
- A rough sketch of the first idea
A constraint is a limit the design must work within, such as budget, size, weight, or available materials.
Odd one outLevel 3
30. Which of these is NOT a step in the engineering design process?
- Build the first idea and never test itcorrect
- Define the problem
- Build a prototype
- Test and improve the design
Good engineering tests and improves ideas, so buying the first idea without testing does not belong.

Where these questions come from. Each unit starts as a plan of the concepts it should cover and the difficulty it should span. Questions are written against that plan with AI assistance, then checked by a validator that rejects anything without a single defensible answer, an explanation, or plausible wrong options. How we write questions sets out the whole process, and corrections are fixed in the bank and reach the site and the app the same day.

How you practise

This unit mixes 14 different question formats, so you are recalling and applying rather than recognising the same layout every time.

Build the sentence
Choose all that apply
Fact or fib
Fill the blank
Guess the number
Match the pairs
Multiple choice
Odd one out
Picture question
Put in order
Sort into groups
Spell it
True or false
Type the answer

Practise Engineering and Design

130 questions across 22 steps. Start with step one and crawl at your own pace.

Play this unit

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