IB DP · Thinka-original Practice Paper

2025 IB DP Design technology Practice Paper with Answers

Thinka Nov 2025 SL IB Diploma Programme-Style Mock — Design technology

80 marks135 mins2025
AnalysisSample paper
An original Thinka practice paper modelled on the structure and difficulty of the Nov 2025 SL IB Diploma Programme Design technology paper. Not affiliated with or reproduced from IB.

Paper 1 (Core SL)

Answer all 30 multiple-choice questions. No calculator allowed.
30 Question · 30 marks
Question 1 · multiple_choice
1 marks
When designing an adjustable office chair, which type of anthropometric or human factors data is most critical for determining the range of height adjustment of the seat relative to the floor?
  1. A.Dynamic anthropometric data of the maximum reach of the arm
  2. B.Static anthropometric data of the popliteal height
  3. C.Physiological data of the cardiovascular endurance of the user
  4. D.Psychological data of the user's perception of comfort
Show answer & marking scheme

Worked solution

Popliteal height is the static anthropometric measurement of the distance from the underside of the foot to the underside of the thigh when sitting. This measurement determines the optimal range of seat height adjustment so that users can sit comfortably with their feet flat on the floor and avoid pressure on the back of the thighs.

Marking scheme

Award 1 mark for selecting B. Reject other options because arm reach (A), cardiovascular endurance (C), and psychological comfort (D) do not dictate seat height adjustment ranges.
Question 2 · multiple_choice
1 marks
Which of the following best describes the practice of "dematerialization" in sustainable product design?
  1. A.Replacing a physical material with a completely biodegradable synthetic alternative
  2. B.Reducing the total volume or weight of materials used in a product without sacrificing its functionality
  3. C.Encouraging customers to return products at the end of their life cycle for component recycling
  4. D.Changing the manufacturing process to use renewable energy sources instead of fossil fuels
Show answer & marking scheme

Worked solution

Dematerialization refers to the reduction of the total material and energy throughput of any product and service. It focuses on using less material to perform the same function, thereby minimizing environmental impacts throughout the product life cycle.

Marking scheme

Award 1 mark for selecting B. Option A is material substitution; Option C is a take-back or recycling strategy; Option D is energy source optimization.
Question 3 · multiple_choice
1 marks
Why would a designer choose to create a physical haptic model of a new hand-held power tool instead of relying solely on a high-fidelity CAD render?
  1. A.To test the structural integrity under simulated stress using Finite Element Analysis (FEA)
  2. B.To accurately determine the manufacturing costs and cycle times of injection molding
  3. C.To evaluate the user's tactile feedback and physical comfort when grasping the tool handle
  4. D.To easily share the design files globally with manufacturing partners for rapid prototyping
Show answer & marking scheme

Worked solution

Haptic modelling relates to the sense of touch and physical interaction. A physical haptic model allows the designer to evaluate how the tool feels in the hand, its weight distribution, grip comfort, and overall physical ergonomics, which cannot be physically felt on a screen.

Marking scheme

Award 1 mark for selecting C. Option A refers to virtual stress testing; Option B refers to manufacturing analysis; Option D refers to digital collaboration.
Question 4 · multiple_choice
1 marks
Shape Memory Alloys (SMAs) are classified as smart materials. What is the primary characteristic that defines a Shape Memory Alloy?
  1. A.They change their electrical resistance when subjected to physical strain
  2. B.They can be deformed when cold, but return to their pre-deformed shape when heated
  3. C.They change color reversibly in response to changes in temperature
  4. D.They produce an electric voltage when mechanical stress is applied
Show answer & marking scheme

Worked solution

Shape Memory Alloys (such as Nitinol) can be plastically deformed at a low temperature, but will return to their original, pre-deformed shape when heated above a specific transition temperature.

Marking scheme

Award 1 mark for selecting B. Option A describes piezoresistive materials; Option C describes thermochromic materials; Option D describes piezoelectric materials.
Question 5 · multiple_choice
1 marks
An electronics manufacturer designs a new smart home thermostat that is compatible with existing electrical wiring and can be installed in under 10 minutes without professional help. According to Rogers' characteristics of innovation, which factor does this ease of installation and integration primarily address to encourage rapid adoption?
  1. A.Observability
  2. B.Trialability
  3. C.Compatibility
  4. D.Relative advantage
Show answer & marking scheme

Worked solution

Compatibility refers to how well an innovation aligns with the values, experiences, and needs of potential adopters. By working with existing household wiring and requiring no special tools, the product is highly compatible with the user's current domestic setup.

Marking scheme

Award 1 mark for selecting C. Option A (observability) is about visibility of results; Option B (trialability) is about testing before purchase; Option D (relative advantage) is how much better it is than the old product.
Question 6 · multiple_choice
1 marks
The Anglepoise lamp is widely considered a classic design. Which characteristic best explains why this product has achieved "timelessness" and remains popular decades after its initial launch?
  1. A.It was designed using advanced CAD simulation tools
  2. B.Its form is so closely linked to its mechanical function that it transcends temporary fashion trends
  3. C.It relies on planned obsolescence to encourage customers to upgrade to newer models
  4. D.It was the first lamp to utilize LED technology for energy efficiency
Show answer & marking scheme

Worked solution

Classic designs often have forms that are deeply integrated with their function. The aesthetic appeal of the Anglepoise lamp comes directly from its constant-tension spring mechanism, which makes its form functional and immune to changing short-term fashion trends.

Marking scheme

Award 1 mark for selecting B. Option A is incorrect as the classic was designed before modern CAD; Option C describes a strategy to limit product life; Option D is historically incorrect.
Question 7 · multiple_choice
1 marks
When designing the height of an emergency exit doorway on a commercial aircraft, which percentile of the target user population should the clearance height be designed for?
  1. A.5th percentile
  2. B.50th percentile
  3. C.95th percentile
  4. D.5th to 95th percentile range
Show answer & marking scheme

Worked solution

For clearance dimensions (like doorways, corridors, or ceiling heights), designers must design for the 95th percentile (the tallest users) to ensure that nearly the entire population can pass through without hitting their heads.

Marking scheme

Award 1 mark for selecting C. Designing for the 5th percentile (A) or 50th percentile (B) would exclude a large percentage of tall users. Designing for the range (D) is appropriate for reach or adjustability, but clearances require an upper extreme limit.
Question 8 · multiple_choice
1 marks
A company takes back used office photocopiers, disassembles them completely, cleans and tests every component, replaces worn-out parts with new ones, and rebuilds them to the original manufacturing specification before selling them with a full warranty. Which waste mitigation strategy does this process describe?
  1. A.Recycling
  2. B.Reconditioning
  3. C.Repairing
  4. D.Re-use
Show answer & marking scheme

Worked solution

Reconditioning (or remanufacturing) is a process of returning a used product to its original factory specifications. It is more thorough than repair, as the product is completely disassembled, rebuilt, and usually sold with a warranty similar to a new product.

Marking scheme

Award 1 mark for selecting B. Recycling (A) involves processing material back into raw states. Repairing (C) is fixing a specific fault without complete rebuilding. Re-use (D) involves using the product again without major disassembly and rebuilding.
Question 9 · Multiple Choice
1 marks
To ensure that a standard task chair's adjustable seat height can be adjusted low enough to accommodate the shortest potential users, which anthropometric measurement should be used to determine the minimum height of the seat?
  1. A.5th percentile female popliteal height
  2. B.95th percentile male popliteal height
  3. C.5th percentile female sitting height
  4. D.95th percentile male sitting height
Show answer & marking scheme

Worked solution

The minimum height of an adjustable chair seat must accommodate users with shorter legs so that their feet can rest flat on the floor. Popliteal height (the distance from the underside of the foot to the underside of the thigh behind the knee) is the relevant anthropometric measurement. Specifically, the 5th percentile female popliteal height is used to determine the lowest setting of the seat height adjustment range.

Marking scheme

Award 1 mark for the correct option. [1 mark total]
- Select A: 5th percentile female popliteal height is correct.
- Reject B: 95th percentile male is used for maximum heights, not minimums.
- Reject C and D: Sitting height measures from the seat to the top of the head, which is not used for seat height adjustment.
Question 10 · Multiple Choice
1 marks
Which of the following strategies specifically describes "dematerialization" in the context of sustainable product design?
  1. A.Replacing a fossil-fuel-based plastic with a biodegradable PLA-based plastic.
  2. B.Reducing the total weight and volume of materials used to manufacture a plastic bottle while maintaining its structural integrity.
  3. C.Setting up a take-back scheme where consumers can return used products for recycling.
  4. D.Standardizing components across different product lines to make repair easier.
Show answer & marking scheme

Worked solution

Dematerialization is the reduction of the total material and energy throughput of any product and service, and thus the limitation of its environmental impact. Reducing the weight and volume of materials used to manufacture a product (such as a plastic bottle) while maintaining its performance is a direct application of dematerialization.

Marking scheme

Award 1 mark for the correct option. [1 mark total]
- Select B: Reducing weight and volume of materials is the definition of dematerialization.
- Reject A: This is material substitution (using bioplastics).
- Reject C: This is a take-back scheme/circular economy strategy.
- Reject D: This is standardization/design for disassembly.
Question 11 · Multiple Choice
1 marks
A design team uses a graphical concept model to communicate the initial layout and user interaction flow of a new mobile app interface. What is a primary limitation of using a conceptual graphical model compared to a physical prototype?
  1. A.It is expensive and time-consuming to modify during early design stages.
  2. B.It cannot represent abstract relationships between different components.
  3. C.It does not allow users to physically experience the tactile feedback and haptic response of the interface.
  4. D.It is difficult to share digitally with remote stakeholders.
Show answer & marking scheme

Worked solution

Graphical models (such as wireframes or flowcharts) are highly effective for visualizing concepts but cannot provide tactile feedback, physical haptic responses, or physical interaction, which are critical aspects of physical prototypes.

Marking scheme

Award 1 mark for the correct option. [1 mark total]
- Select C: Graphical models lack physical and tactile user interaction.
- Reject A: Graphical models are typically very cheap and fast to modify.
- Reject B: Conceptual models excel at representing abstract relationships.
- Reject D: Graphical models are very easy to share digitally.
Question 12 · Multiple Choice
1 marks
Which property of natural timber is primarily responsible for its tendency to warp, shrink, or swell unevenly when exposed to changes in environmental humidity?
  1. A.Tensile strength
  2. B.Plasticity
  3. C.Anisotropy
  4. D.Thermal conductivity
Show answer & marking scheme

Worked solution

Wood is an anisotropic material. Anisotropy means that its physical properties (such as moisture absorption and subsequent dimensional movement) are different when measured along different axes (radial, tangential, and longitudinal directions relative to the grain). This leads to uneven warping and shrinking.

Marking scheme

Award 1 mark for the correct option. [1 mark total]
- Select C: Anisotropy explains the directional differences in dimensional change.
- Reject A: Tensile strength relates to load-bearing capacity, not moisture response.
- Reject B: Plasticity is the ability to deform permanently without rupture, not related to moisture warping.
- Reject D: Thermal conductivity relates to heat transfer.
Question 13 · Multiple Choice
1 marks
Which of the following scenarios is an example of a "market pull" driver for innovation?
  1. A.A research laboratory develops a new ultra-conductive material, leading designers to find a use for it in consumer electronics.
  2. B.Consumers demand quieter and more energy-efficient vacuum cleaners, prompting manufacturers to develop new motor designs.
  3. C.The discovery of high-temperature superconductivity inspires a company to create magnetic levitation toys.
  4. D.A breakthrough in microprocessor manufacturing enables computers to perform twice as fast for the same cost.
Show answer & marking scheme

Worked solution

"Market pull" occurs when an innovation is driven by demand or consumer needs in the marketplace. Consumers requesting quieter and more energy-efficient vacuum cleaners forces manufacturers to develop solutions, representing market pull. The other options describe technology push, where scientific discovery or technological advancement drives the creation of new products.

Marking scheme

Award 1 mark for the correct option. [1 mark total]
- Select B: Market demands directly pull the development of the technology.
- Reject A, C, and D: These are technology push scenarios, where new technology is looking for a market application.
Question 14 · Multiple Choice
1 marks
Why does a classic design, such as the Anglepoise lamp or the original Vespa scooter, continue to be demanded long after its initial technology has been superseded?
  1. A.It is always cheaper to manufacture than modern equivalents.
  2. B.It possesses a timeless aesthetic and nostalgic value that transcends its functional obsolescence.
  3. C.It has no competition from newer, more efficient designs.
  4. D.It is designed with planned obsolescence in mind, forcing consumers to re-purchase it regularly.
Show answer & marking scheme

Worked solution

Classic designs possess timeless aesthetics, iconic status, and nostalgic value that build an emotional connection with consumers. This allows them to remain highly desirable and demanded even when technically superior or more modern alternatives exist.

Marking scheme

Award 1 mark for the correct option. [1 mark total]
- Select B: The core value of classic design lies in its timeless appeal and image.
- Reject A: Classic designs are often more expensive to buy or manufacture due to premium branding.
- Reject C: Newer, more efficient designs do exist and compete with them.
- Reject D: Planned obsolescence is the opposite of classic design longevity.
Question 15 · Multiple Choice
1 marks
A designer is developing a new handle for hand-held power tools. To reduce the risk of Hand-Arm Vibration Syndrome (HAVS) in operators, which ergonomic strategy should be implemented?
  1. A.Using a highly polished, rigid metal handle to maximize grip traction.
  2. B.Incorporating elastomer-dampened grips that absorb high-frequency oscillations.
  3. C.Increasing the weight of the tool's motor to stabilize the user's arm.
  4. D.Designing a square-edged handle to prevent the tool from twisting in the hand.
Show answer & marking scheme

Worked solution

Hand-Arm Vibration Syndrome (HAVS) is a physiological issue caused by exposure to vibrations from power tools. Using elastomer-dampened grips helps absorb and dissipate these high-frequency oscillations, protecting the user's muscles, nerves, and joints.

Marking scheme

Award 1 mark for the correct option. [1 mark total]
- Select B: Elastomeric materials dampen the physical vibrations responsible for HAVS.
- Reject A: Rigid, highly polished metal would transmit all vibrations directly to the hand.
- Reject C: Increasing motor weight increases physical strain on the arm.
- Reject D: Square edges create pressure points, worsening physical fatigue.
Question 16 · Multiple Choice
1 marks
Which manufacturing process involves forcing molten thermoplastic under high pressure into a closed, multi-part steel mold cavity to produce complex 3D shapes with high dimensional accuracy and consistency?
  1. A.Blow moulding
  2. B.Rotational moulding
  3. C.Injection moulding
  4. D.Compression moulding
Show answer & marking scheme

Worked solution

Injection moulding involves forcing molten plastic under high pressure into a closed steel mould. It is ideal for producing highly complex 3D plastic components with high dimensional accuracy and tight tolerances at high production volumes.

Marking scheme

Award 1 mark for the correct option. [1 mark total]
- Select C: Injection moulding matches the description of molten plastic under high pressure in a closed mold.
- Reject A: Blow moulding is used for hollow thin-walled objects like bottles.
- Reject B: Rotational moulding is used for large hollow shapes without pressure.
- Reject D: Compression moulding is typically used for thermosets and involves compressing a preform, not injecting molten plastic under high pressure.
Question 17 · Multiple Choice
1 marks
Standard anthropometric practice for designing an adjustable office chair seat height aims to accommodate 90% of the target population. Which percentile range is typically selected to determine this adjustability range?
  1. A.1st percentile to 91st percentile
  2. B.5th percentile to 95th percentile
  3. C.10th percentile to 100th percentile
  4. D.50th percentile only
Show answer & marking scheme

Worked solution

To design an adjustable product (like an office chair) that accommodates 90% of a target population, designers typically exclude the extreme 5% at both ends of the spectrum (the smallest 5% and the largest 5%). This leaves the 5th to 95th percentile range, which accommodates exactly 90% of the population while keeping production and adjustability mechanism costs feasible.

Marking scheme

Award 1 mark for identifying the correct percentile range (B).
Question 18 · Multiple Choice
1 marks
Which of the following characteristics is classified as a physiological factor in ergonomics?
  1. A.Reach and clearance
  2. B.Muscle strength and fatigue
  3. C.Mental workload and attention
  4. D.Acoustic and lighting levels
Show answer & marking scheme

Worked solution

Physiological human factors relate to the body's physical tolerances and capabilities, such as muscle strength, cardiovascular endurance, fatigue, and physical endurance. Reach and clearance are anthropometric/physical factors. Mental workload is a cognitive factor. Acoustic and lighting levels are environmental factors.

Marking scheme

Award 1 mark for selecting B.
Question 19 · Multiple Choice
1 marks
At which stage of a product's Life Cycle Analysis (LCA) are the environmental impacts associated with raw material extraction and the processing of raw materials into bulk materials evaluated?
  1. A.Pre-production
  2. B.Production
  3. C.Distribution
  4. D.Utilization
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Worked solution

The pre-production stage of a Life Cycle Analysis (LCA) encompasses all activities prior to the actual manufacture of the product. This includes the extraction of raw materials (such as mining or harvesting) and their initial processing into industrial materials.

Marking scheme

Award 1 mark for selecting A.
Question 20 · Multiple Choice
1 marks
An industrial designer wants to evaluate the fluid dynamics and drag coefficient of a conceptual sports car body. Which of the following digital models would be most appropriate to obtain quantitative aerodynamic data?
  1. A.Finite element analysis (FEA) model
  2. B.Computational fluid dynamics (CFD) model
  3. C.3D surface model
  4. D.Virtual reality (VR) model
Show answer & marking scheme

Worked solution

Computational fluid dynamics (CFD) is a digital tool used specifically to simulate the behavior of gases and liquids interacting with surfaces. It provides quantitative data regarding drag coefficients, aerodynamics, and fluid flow around a product. Finite element analysis (FEA) is used for stress and structural analysis. Surface models define shape without physical simulation, and VR is for visual interaction.

Marking scheme

Award 1 mark for selecting B.
Question 21 · Multiple Choice
1 marks
Why is seasoned timber preferred over green timber for high-quality furniture manufacturing?
  1. A.Seasoned timber has a higher moisture content, which makes it more pliable and easier to bend.
  2. B.Seasoned timber is highly combustible, making it easier to heat-treat.
  3. C.Seasoned timber is less prone to warping, splitting, and fungal decay due to its lower moisture content.
  4. D.Seasoned timber is much softer, allowing for faster machining and carving.
Show answer & marking scheme

Worked solution

Seasoning is the process of drying timber to reduce its moisture content to match the environmental conditions where it will be used. This significantly increases its dimensional stability, making it far less prone to warping, splitting, checking, or rotting compared to green (unseasoned) timber.

Marking scheme

Award 1 mark for selecting C.
Question 22 · Multiple Choice
1 marks
Which manufacturing process is most suitable for producing large, hollow, stress-free plastic containers, such as outdoor water storage tanks?
  1. A.Injection moulding
  2. B.Rotational moulding
  3. C.Compression moulding
  4. D.Line bending
Show answer & marking scheme

Worked solution

Rotational moulding (rotomolding) is ideal for producing large, hollow, seamless plastic products. The process involves heated hollow moulds filled with plastic powder that are rotated on biaxial axes, ensuring uniform wall thickness and stress-free parts, which are essential for durable large tanks.

Marking scheme

Award 1 mark for selecting B.
Question 23 · Multiple Choice
1 marks
A smartphone manufacturer releases a new model that features an incremental improvement to the camera resolution and a slightly faster processor, while maintaining the same operating system and user interface. Which type of innovation does this release represent?
  1. A.Disruptive innovation
  2. B.Architectural innovation
  3. C.Sustaining innovation
  4. D.Radical innovation
Show answer & marking scheme

Worked solution

Sustaining innovation involves continuous, incremental improvements to an existing product to maintain its competitiveness in an established market. It does not create new markets or disrupt existing ones but builds on existing technological trajectories.

Marking scheme

Award 1 mark for selecting C.
Question 24 · Multiple Choice
1 marks
A classic design often transcends its original functional purpose to become a symbol of a particular era, lifestyle, or social status. Which characteristic of classic design best describes this phenomenon?
  1. A.Form follows function
  2. B.Planned obsolescence
  3. C.Retro-styling
  4. D.Status and image
Show answer & marking scheme

Worked solution

Classic designs often acquire a powerful 'status and image' that makes them highly desirable even when technologically outdated. They become cultural icons, projecting a specific taste, wealth, or appreciation of design history, transcending simple utilitarian use.

Marking scheme

Award 1 mark for selecting D.
Question 25 · Multiple Choice
1 marks
A designer is developing an adjustable task chair for a shared office environment. To ensure comfort and support for the widest range of users, the height of the seat must be adjustable. Which anthropometric measurement should be used to determine the minimum and maximum height limits of the seat?
  1. A.Hip breadth and thigh clearance
  2. B.Sitting height and eye height
  3. C.Popliteal height of the 5th percentile female and the 95th percentile male
  4. D.Buttock-popliteal length of the 5th percentile male and the 95th percentile female
Show answer & marking scheme

Worked solution

Popliteal height is the distance from the underside of the foot to the underside of the thigh when sitting. It is the critical anthropometric measurement for determining seat height. To accommodate 90% of the population, the seat adjustment must range from the 5th percentile female value (to ensure short legs can touch the floor) to the 95th percentile male value (to ensure tall legs are comfortable).

Marking scheme

Award 1 mark for the correct answer C. Popliteal height is the correct ergonomic dimension for seat height. To accommodate 90% of users, the 5th percentile female value is the lower limit and the 95th percentile male value is the upper limit.
Question 26 · Multiple Choice
1 marks
A commercial laundry detergent manufacturer shifts from selling liquid detergent in single-use HDPE bottles to selling concentrated detergent sheets in biodegradable cardboard envelopes. This change significantly reduces the overall volume of packaging required and minimizes transport emissions. Which waste mitigation strategy is primarily demonstrated by this redesign?
  1. A.Recycling
  2. B.Dematerialization
  3. C.Reconditioning
  4. D.Regenerating
Show answer & marking scheme

Worked solution

Dematerialization is the reduction of total material and energy throughput of any product and service. By replacing liquid detergent (which contains high water weight) and bulky plastic bottles with lightweight concentrated sheets in minimal cardboard packaging, the company has drastically reduced the material and resource use, which is a key example of dematerialization.

Marking scheme

Award 1 mark for the correct answer B. Dematerialization refers to reducing the quantity of materials used in a product's lifecycle. Other options do not describe the reduction of raw material content and packaging volume at the source.
Question 27 · Multiple Choice
1 marks
An architectural firm builds a 1:100 scale model of a proposed museum using cardboard and 3D-printed plastic. The model does not include internal structures or functional windows, but is used in presentations to show clients how the building's exterior form will interact with the surrounding cityscape. What type of physical model is this?
  1. A.Instrument model
  2. B.Prototype
  3. C.Aesthetic model
  4. D.Mock-up
Show answer & marking scheme

Worked solution

An aesthetic model is a model developed to look and feel like the final product, used to communicate the visual appeal and form of the design to clients and stakeholders. It does not contain working internal components or full structural fidelity, which distinguishes it from prototypes or mock-ups.

Marking scheme

Award 1 mark for the correct answer C. Aesthetic models are scale or full-sized representations used primarily for visual evaluation and presentation. Award 0 marks for options a, b, or d which require functional elements, data acquisition, or ergonomic layout testing.
Question 28 · Multiple Choice
1 marks
A manufacturing company needs to produce a high volume of plastic storage bins with complex interior ribs for strength and precise snap-fit lids. Which manufacturing process is most appropriate for producing these high-tolerance components efficiently?
  1. A.Rotational moulding
  2. B.Blow moulding
  3. C.Vacuum forming
  4. D.Injection moulding
Show answer & marking scheme

Worked solution

Injection moulding is highly suitable for high-volume production of thermoplastic parts that require high dimensional accuracy, intricate details (such as snap-fits), and complex geometry (such as internal reinforcing ribs). Processes like blow moulding and rotational moulding are used for hollow containers, while vacuum forming cannot produce complex internal ribs or high-tolerance snap-fits.

Marking scheme

Award 1 mark for the correct answer D. Injection moulding is characterized by high precision, suitability for complex solid/semi-open parts with ribs and bosses, and high-volume cost efficiency.
Question 29 · Multiple Choice
1 marks
A smartphone manufacturer releases its yearly flagship phone. The new model features an upgraded camera sensor and a slightly faster processor, but retains the exact same chassis design, software interface, and user experience as the previous version. Which type of innovation does this release represent?
  1. A.Radical innovation
  2. B.Incremental innovation
  3. C.Disruptive innovation
  4. D.Process innovation
Show answer & marking scheme

Worked solution

Incremental innovation involves small, continuous refinements and updates to an existing product to improve its performance or reduce cost, without changing its fundamental nature or creating a completely new market.

Marking scheme

Award 1 mark for the correct answer B. Incremental innovation represents step-by-step performance upgrades (such as a faster processor or better sensor) to an existing product architecture.
Question 30 · Multiple Choice
1 marks
The Barcelona Chair, designed by Ludwig Mies van der Rohe in 1929, continues to be manufactured and purchased worldwide today. Its enduring appeal is largely due to its timeless aesthetic form rather than any recent technological improvements. Which type of obsolescence has this classic design successfully resisted?
  1. A.Planned obsolescence
  2. B.Functional obsolescence
  3. C.Style obsolescence
  4. D.Technological obsolescence
Show answer & marking scheme

Worked solution

Style (or aesthetic) obsolescence occurs when a product becomes undesirable because it is no longer fashionable or in style. Classic designs resist style obsolescence because their design is considered timeless, maintaining their appeal and status across generations despite changing trends.

Marking scheme

Award 1 mark for the correct answer C. Style obsolescence is the correct term for losing appeal due to changing fashion/trends. Classic designs specifically resist style obsolescence because of their timeless aesthetic.

Paper 2 Section A

Answer all compulsory structured and data-based questions in the spaces provided. A calculator is required.
10 Question · 30 marks
Question 1 · Data-Based Short Answer
3 marks
A design team is compiling anthropometric data to design an adjustable office chair. The 5th percentile female popliteal height is recorded as \(355\text{ mm}\), and the 95th percentile male popliteal height is recorded as \(480\text{ mm}\). Calculate the total range of height adjustability required to accommodate this user cohort, and state one ergonomic consequence if the chair cannot adjust low enough for the 5th percentile female user.
Show answer & marking scheme

Worked solution

First, calculate the adjustability range by finding the difference between the 95th percentile and the 5th percentile measurements: \(480\text{ mm} - 355\text{ mm} = 125\text{ mm}\). Second, if the chair is too high for the 5th percentile user, their feet will dangle, creating pressure points on the underside of their thighs, which can restrict blood circulation and cause discomfort.

Marking scheme

[1 mark] for calculating the correct adjustability range: \(125\text{ mm}\) (allow correct unit omission if implied).
[2 marks] for stating the ergonomic consequence: Award [1 mark] for identifying pressure on thighs/feet dangling and [1 mark] for linking this to restricted blood circulation, muscle fatigue, or physical discomfort.
Question 2 · Data-Based Short Answer
3 marks
An LCA analyst compares the energy footprint of two packaging options using the formula \(E_{\text{net}} = E_{\text{mfg}} \times (1 - R) + E_{\text{rec}} \times R\) (where \(E_{\text{mfg}}\) is manufacturing energy, \(E_{\text{rec}}\) is recycling energy, and \(R\) is the recycling rate expressed as a decimal). Container A has \(E_{\text{mfg}} = 3.2\text{ MJ}\), \(E_{\text{rec}} = 1.8\text{ MJ}\), and \(R = 0.40\). Container B has \(E_{\text{mfg}} = 6.0\text{ MJ}\), \(E_{\text{rec}} = 0.6\text{ MJ}\), and \(R = 0.70\). Calculate the net energy consumption for both containers and state which container is more energy-efficient under these conditions.
Show answer & marking scheme

Worked solution

For Container A: \(E_{\text{net}} = 3.2 \times (1 - 0.40) + 1.8 \times 0.40 = 3.2 \times 0.60 + 0.72 = 1.92 + 0.72 = 2.64\text{ MJ}\). For Container B: \(E_{\text{net}} = 6.0 \times (1 - 0.70) + 0.6 \times 0.70 = 6.0 \times 0.30 + 0.42 = 1.80 + 0.42 = 2.22\text{ MJ}\). Comparing the results, Container B (2.22 MJ) is more energy-efficient than Container A (2.64 MJ).

Marking scheme

[1 mark] for calculating Container A's net energy as \(2.64\text{ MJ}\).
[1 mark] for calculating Container B's net energy as \(2.22\text{ MJ}\).
[1 mark] for correctly identifying that Container B is more energy-efficient based on the calculations.
Question 3 · Data-Based Short Answer
3 marks
A tech company redesigned its phone packaging, reducing the weight of the cardboard box from \(180\text{ g}\) to \(108\text{ g}\). Calculate the percentage reduction in packaging weight achieved through this dematerialization, and explain one environmental benefit of this change during the distribution phase.
Show answer & marking scheme

Worked solution

Percentage reduction is calculated as: \(((180 - 108) / 180) \times 100 = (72 / 180) \times 100 = 40\%\). Lighter packaging means that the total weight of the shipping cargo is reduced. This reduces the fuel consumption of transport vehicles, leading to lower carbon dioxide and other greenhouse gas emissions during distribution.

Marking scheme

[1 mark] for the correct calculation of \(40\%\) weight reduction.
[2 marks] for the explanation of the environmental benefit: Award [1 mark] for identifying that lighter loads reduce fuel requirements/allow more products to be shipped at once, and [1 mark] for linking this directly to decreased greenhouse gas emissions or carbon footprint during transit.
Question 4 · Data-Based Short Answer
3 marks
A design team compares physical wind tunnel testing with Computational Fluid Dynamics (CFD) modeling. Physical wind tunnel testing costs \(\$15,000\) and takes \(120\text{ hours}\). CFD testing costs \(\$2,500\) and takes \(8\text{ hours}\). Calculate the percentage cost savings of using CFD over physical testing, and suggest why a team might still execute a physical test for the final design validation.
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Worked solution

The percentage savings is calculated as: \(((\$15,000 - \$2,500) / \$15,000) \times 100 = (\$12,500 / \$15,000) \times 100 = 83.33\%\) (or \(83.3\%\)). Physical testing is still used at the final stage because computer models (CFD) rely on simplified mathematical assumptions. Physical testing provides empirical validation of the design under real-world conditions, ensuring no critical variables were missed in the digital environment.

Marking scheme

[1 mark] for the correct cost savings calculation: \(83.3\%\) (accept \(83\%\) or \(83.33\%\)).
[2 marks] for the justification: Award [1 mark] for explaining that digital simulations have limitations/simplifications, and [1 mark] for explaining that physical testing provides authentic, empirical proof under real-world conditions before committing to mass production.
Question 5 · Data-Based Short Answer
3 marks
A laboratory tests two polymers for use in the outer shell of a protective safety helmet. Polymer X has an ultimate tensile strength of \(45\text{ MPa}\) and an elongation at break of \(15\%\). Polymer Y has an ultimate tensile strength of \(30\text{ MPa}\) and an elongation at break of \(150\%\). State which polymer is more suitable for absorbing heavy impact energy, and justify your choice with reference to their material properties.
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Worked solution

Polymer Y is more suitable. While Polymer X has higher tensile strength, its low elongation (15%) indicates it is brittle and prone to cracking under impact. Polymer Y has a much higher elongation at break (150%), meaning it is highly ductile. The combination of its strength and high elongation gives Polymer Y high toughness (area under the stress-strain curve), enabling it to deform plastically and absorb substantial impact energy without fracturing.

Marking scheme

[1 mark] for selecting Polymer Y.
[2 marks] for the justification: Award [1 mark] for explaining that Polymer Y has high ductility/elongation at break, and [1 mark] for connecting this to toughness/the ability of the material to deform and absorb energy rather than shattering instantly (unlike Polymer X).
Question 6 · Data-Based Short Answer
3 marks
According to Rogers' Diffusion of Innovation curve, early market adoption is divided into Innovators (\(2.5\%\)), Early Adopters (\(13.5\%\)), and the Early Majority (\(34\%\)). Calculate the cumulative market share represented by these three categories combined, and explain how the unique social characteristics of 'Early Adopters' help drive adoption into the 'Early Majority'.
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Worked solution

The cumulative market share is: \(2.5\% + 13.5\% + 34\% = 50\%\). Early Adopters are typically respected opinion leaders within their social circles. Unlike Innovators, who are seen as risk-tolerant eccentrics, the Early Adopters' endorsement of a product signals safety and utility, which legitimizes the technology and helps convince the more risk-averse Early Majority to adopt it.

Marking scheme

[1 mark] for the correct cumulative percentage: \(50\%\).
[2 marks] for the explanation of Early Adopters' influence: Award [1 mark] for identifying them as opinion leaders or trendsetters with high social status, and [1 mark] for explaining how their endorsement lowers the perceived risk/provides validation for the cautious Early Majority.
Question 7 · Data-Based Short Answer
3 marks
A consumer study compares a classic mid-century lounge chair with a trend-based fast-furniture chair. The classic chair has an average ownership life of \(18\text{ years}\) and retains \(75\%\) of its resale value. The trend-based chair has an average ownership life of \(3\text{ years}\) and retains \(10\%\) of its resale value. Calculate the ratio of ownership longevity between the classic and trend-based chairs, and explain how 'timeless aesthetics' contributes to the classic chair's high resale value.
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Worked solution

The ratio of ownership longevity is \(18\text{ years} : 3\text{ years} = 6:1\) (or simply \(6\) times longer). Timeless aesthetics ensure that the classic chair does not look outdated or unfashionable as temporary design trends shift. Because the visual appeal of the design remains strong over generations, demand in the secondhand market remains high, allowing the owner to recoup a substantial portion of their original investment.

Marking scheme

[1 mark] for the correct longevity ratio: \(6:1\) (or \(6\)).
[2 marks] for the explanation of resale value: Award [1 mark] for noting that timeless aesthetics transcend fleeting style trends, and [1 mark] for explaining how this sustained desirability keeps demand high and supports high resale prices.
Question 8 · Data-Based Short Answer
3 marks
A manufacturing plant increased its output of consumer electronics from \(10,000\) to \(15,000\) units (a \(50\%\) increase) while its total carbon dioxide emissions decreased from \(500\text{ tonnes}\) to \(450\text{ tonnes}\) (a \(10\%\) decrease). State whether this represents absolute or relative decoupling of environmental impact from economic growth, and justify your response using the data.
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Worked solution

This scenario represents absolute decoupling. Absolute decoupling occurs when economic or production output grows while the resource use or environmental impact decreases in absolute terms. In this case, the economic output grew by \(50\%\), but the actual quantity of carbon emissions fell by \(10\%\) (from \(500\) to \(450\text{ tonnes}\)), demonstrating a complete break in the link between growth and pollution.

Marking scheme

[1 mark] for stating 'Absolute decoupling'.
[2 marks] for the justification: Award [1 mark] for defining/identifying that output increased (by \(50\%\)) and [1 mark] for pointing out that the absolute environmental impact decreased (by \(10\%\) / \(50\text{ tonnes}\)), rather than just growing at a slower rate than production (which would be relative).
Question 9 · short-answer
3 marks
A design team is comparing two plastics for a new high-volume beverage bottle distributed in a region with standard municipal recycling bins but no industrial composting facilities:

* **Polyethylene Terephthalate (PET):** Embodied energy = \( 80 \text{ MJ/kg} \); Recyclability = High (closed-loop infrastructure available).
* **Polylactic Acid (PLA):** Embodied energy = \( 54 \text{ MJ/kg} \); Recyclability = Low (requires industrial composting to biodegrade).

Explain why a designer whose primary goal is to minimize municipal landfill waste might choose PET over PLA for this product, despite PLA having lower embodied energy.
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Worked solution

Although PLA has a lower environmental impact in terms of energy consumption during production (embodied energy), its end-of-life path is highly dependent on specialized infrastructure. PLA is not home-compostable and does not break down efficiently in standard landfill conditions. Without industrial composting facilities, PLA bottles will either contaminate existing PET recycling streams or be directed straight to landfill, where they remain intact. On the other hand, PET has highly established municipal recycling infrastructure, allowing the material to be recovered, recycled, and kept out of the waste stream entirely.

Marking scheme

Award 1 mark for identifying that PLA requires specialized industrial composting infrastructure that is absent in the region (meaning it will not biodegrade in standard landfills).
Award 1 mark for explaining that PLA can contaminate existing polymer recycling streams if mixed.
Award 1 mark for explaining that PET has an established closed-loop recycling infrastructure which allows it to be diverted from landfills successfully.
Question 10 · short-answer
3 marks
An ergonomics team compiles the following popliteal height percentile data for their target adult user population to design an adjustable task chair:

* 5th Percentile: \( 390 \text{ mm} \)
* 50th Percentile: \( 440 \text{ mm} \)
* 95th Percentile: \( 490 \text{ mm} \)

State the minimum range of height adjustability required to accommodate the 5th to 95th percentile of this population, and explain why designing the seat at a fixed height using only the 50th percentile value would lead to physical discomfort for a large portion of users.
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Worked solution

To find the adjustability range, subtract the 5th percentile popliteal height from the 95th percentile popliteal height: \( 490 \text{ mm} - 390 \text{ mm} = 100 \text{ mm} \). The seat must adjust from at least \( 390 \text{ mm} \) to \( 490 \text{ mm} \). Designing a fixed seat at the 50th percentile (\( 440 \text{ mm} \)) is inappropriate because it assumes an "average" user fits all. Users in the lower percentiles (shorter legs) will have their feet dangling, causing uncomfortable pressure on the back of their thighs and restricting circulation. Conversely, users in the higher percentiles (longer legs) will find the seat too low, forcing their knees upward and leading to poor lumbar support.

Marking scheme

Award 1 mark for calculating the correct range of adjustability (\( 100 \text{ mm} \) or identifying the seat must adjust from \( 390 \text{ mm} \) to \( 490 \text{ mm} \)).
Award 1 mark for explaining that a 50th percentile fixed design fails to accommodate users on either end of the spectrum (shorter/taller users).
Award 1 mark for describing a specific physiological consequence of an incorrect seat height (e.g., circulation restriction under thighs for 5th percentile, or poor posture/lumbar support for 95th percentile).

Paper 2 Section B

Select and answer ONE full extended-response question from the options provided.
1 Question · 20 marks
Question 1 · Structured Essay
20 marks

Context:
A design company has launched 'LoopSeat', a modular high chair for infants and toddlers. LoopSeat is offered through a subscription-based Product-Service System (PSS) where parents rent the chair. As the child grows, modules (such as the infant support unit, food tray, or safety harness) are returned to the manufacturer to be refurbished, remanufactured, or composted. The chair is constructed from sustainably sourced bamboo and a bio-based compostable polymer.

Questions:
(a) State two benefits of using sustainably sourced bamboo instead of a traditional hardwood for the structural frame of the high chair. [2 marks]

(b) Explain how the concept of 'design for disassembly' is applied to the modular high chair to support sustainable resource management. [4 marks]

(c) Explain how the subscription-based Product-Service System (PSS) benefits both the manufacturer and the consumer. [6 marks]

(d) Discuss how 'LoopSeat' addresses the principles of a circular economy in terms of waste mitigation and material flows. [8 marks]

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Worked solution

Part (a) [2 marks]
Any two of the following:
- Bamboo is a highly renewable resource because it is one of the fastest-growing plants on Earth, whereas traditional hardwoods can take decades to mature. This reduces the depletion rate of slow-growing forest resources.
- Bamboo acts as a rapid carbon sink during its growth phase, absorbing carbon dioxide and releasing oxygen more quickly than most hardwoods, reducing the overall carbon footprint of raw material sourcing.
- Bamboo has a high strength-to-weight ratio, allowing for a lightweight but durable frame, which can reduce transport emissions during distribution.

Part (b) [4 marks]
To support sustainable resource management, design for disassembly is applied in the following ways:
- Reversible joining techniques: The chair uses mechanical fasteners (such as screws, bolts, or snap-fits) instead of permanent chemical adhesives. This allows the consumer or manufacturer to easily separate parts without damaging them.
- Material separation: Because parts are easily disassembled, the bamboo frame elements can be cleanly isolated from the bio-based polymer tray and safety harness components. This prevents material contamination, enabling pure recycling/composting streams.
- Targeted repair/upgrades: When a single component wears out or is outgrown (e.g., the food tray), only that module needs to be detached and replaced, rather than discarding the entire high chair. This extends the life cycle of the main structural elements.

Part (c) [6 marks]
Benefits to the Manufacturer (Max 3 marks):
- Secures recurring revenue: Rather than a single transaction, the subscription model provides steady, predictable income over the child's development period.
- Resource recovery and cost savings: By retaining ownership of the product, the manufacturer recovers high-value components (like bamboo frames) at the end of a subscription. These can be cleaned, refurbished, and rented again, reducing raw material procurement costs.
- Customer relationship and brand loyalty: Ongoing contact during module swaps allows the manufacturer to offer superior service, collect user feedback for product development, and build strong brand trust.

Benefits to the Consumer (Max 3 marks):
- Lower initial cost barrier: Consumers do not need to pay a high upfront price to purchase a premium, sustainable high chair; instead, they pay manageable monthly/annual subscription fees.
- Elimination of disposal/storage hassle: Once the child outgrows the high chair, parents do not need to store a bulky, unused item or find a way to dispose of it responsibly; the manufacturer simply takes it back.
- Access to developmentally appropriate configurations: Parents automatically receive the exact modules needed for their child's developmental stage (e.g., infant insert swapped for a toddler seat) without having to buy separate items.

Part (d) [8 marks]
A comprehensive discussion should evaluate how the design and business model align with circular economy principles:
- Biological Nutrients (Closing the Loop): The use of bio-based compostable polymers and bamboo means that worn-out components can enter the biological cycle. When these parts reach the end of their useful life, they can be safely composted to return nutrients back to the biosphere without toxic chemical residues.
- Technical Nutrients (Remanufacturing): For components that are not biodegradable or are designed for long-term mechanical wear, the PSS model ensures they stay in the technical cycle. The manufacturer can refurbish and remanufacture structural parts, maintaining their highest utility and value at all times.
- Waste Mitigation (Shifting from Linear to Circular): Traditional children's furniture is highly linear ('take-make-waste'), often discarded to landfills after a few years of use. LoopSeat minimizes municipal waste by designing modules to be continuously re-used across multiple customer families.
- Dematerialization and System-level Resource Efficiency: Because multiple families use the same high chair sequentially via subscription, fewer overall physical products need to be manufactured to serve the same market size. This dramatically lowers the global demand for raw material extraction and energy-intensive manufacturing processes.

Marking scheme

Part (a) Marking Scheme:
- 1 mark for each valid benefit stated, up to 2 marks maximum.
- Accept: Rapid growth/renewability, carbon sequestration, strength-to-weight ratio (reducing transport impact).
- Reject: Vague terms like "eco-friendly" or "green" without explanation.

Part (b) Marking Scheme:
- Award 1 mark for identifying a disassembly feature (e.g., non-permanent joints/screws).
- Award 1 mark for explaining how this feature relates to modularity/component separation.
- Award 1 mark for linking separation to specific material streams (bamboo vs. polymer).
- Award 1 mark for explaining the outcome of sustainable resource management (e.g., life extension, preventing landfilling).

Part (c) Marking Scheme:
- Manufacturer benefits (Max 3 marks): 1 mark for each clearly explained benefit (e.g., recurring revenue, raw material recovery, brand loyalty).
- Consumer benefits (Max 3 marks): 1 mark for each clearly explained benefit (e.g., affordability, no storage clutter, flexible configuration upgrades).

Part (d) Rubric-based Marking (8 marks total):
- 7-8 marks: The candidate shows a deep understanding of circular economy principles. Clearly discusses both biological and technical nutrient loops, waste mitigation, and systemic resource efficiency (dematerialization). High-quality linkages are made to the LoopSeat context (bamboo, biopolymer, subscription PSS).
- 5-6 marks: The candidate discusses at least two main aspects of circular economy (e.g., biological/technical loops and waste reduction) with good explanations and reference to the product context.
- 3-4 marks: The candidate outlines circular economy principles but the linkages to LoopSeat are superficial, or the discussion focuses on general recycling rather than circular systemic design.
- 1-2 marks: The candidate provides simple, isolated points about recycling or sustainability with little or no structure or connection to the circular economy framework.

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