Material classification helps designers compare materials and select the most suitable option for a product or manufacturing process. Materials can be grouped by their source, structure, properties and behaviour.
Designers need to understand how materials perform so they can choose materials that are strong enough, safe to use, suitable for manufacture, appropriate for the user and suitable for the product’s environment.
Materials can be classified as natural or human-made.
Natural materials come from plants, animals or the earth. Examples include timber, cotton, wool and natural rubber.
Human-made materials are manufactured or engineered by people. Examples include polymers, metals, glass, textiles, metals, composites, smart materials and biomaterials.
Materials may also be used in different types of structures, such as frame structures, shell structures, solid structures or combination structures.
Designers select materials by considering their physical, chemical and mechanical properties.
Physical properties can be observed or measured without changing the material. These include density, thermal conductivity, thermal expansion, melting point, electrical conductivity and electrical resistivity.
Chemical properties describe how a material reacts with other substances or environments. These include corrosion resistance, reactivity, food safety, hygroscopy and flammability.
Mechanical properties describe how a material behaves when forces are applied. These include tensile strength, compressive strength, stiffness, toughness, hardness, malleability, elasticity, plasticity and ductility.
Composites are made by combining two or more materials to improve performance. For example, carbon fibre reinforced polymer is lightweight and strong, making it suitable for sports equipment, bikes and automotive parts.
Smart materials change their properties in response to external stimuli such as heat, light, pressure, electricity or magnetic fields. Examples include shape memory alloys, photochromic materials, piezoelectric materials and thermoelectric materials.
Biodegradable materials can break down after disposal or at the end of their useful life. These materials can support sustainability and circular design by helping reduce long-term waste.
Material selection is not just about choosing what looks good. Designers must choose materials based on performance, safety, manufacturing, sustainability and the context of use.
What material has been used and why might it be suitable?
Is the material natural, human-made, composite, smart or biodegradable?
What physical properties are important for this product?
What chemical properties could affect safety or durability?
What mechanical properties are needed for the product to perform well?
How do the material properties affect the manufacturing process?
Could a different material improve the product’s performance or sustainability?
What limitations does the material create for the design?
Material Properties GCSE DT
A relevant Design & Technology video that explains material properties and how they influence material selection.
https://www.youtube.com/watch?v=dG6BTfS52HE
Modern and Smart Materials GCSE DT
Useful for understanding smart materials and how they respond to changes such as heat, light or pressure.
https://www.youtube.com/watch?v=ggQjmN3N92w
HL only
Structural systems are designed to support loads and resist forces without failing. Designers need to understand how structures behave so they can create products, buildings and components that are safe, stable and suitable for their intended use.
A structure may need to resist different types of forces, including tension, compression, bending, torsion and shear. The way a structure performs depends on its shape, material, joints, supports and how the load is applied.
Frame structures
Frame structures are made from connected members, such as beams, columns or rods. They are often lightweight but strong. Examples include bicycle frames, chair frames, bridges and scaffolding.
Shell structures
Shell structures use a thin outer surface to support loads and protect what is inside. Examples include helmets, car bodies, bottles and packaging.
Solid structures
Solid structures rely on the strength and mass of the material. Examples include concrete blocks, walls, dams and some furniture components.
Combination structures
Many products use more than one type of structure. For example, a chair may have a frame structure for support and a shell structure for the seat.
Designers must consider how forces affect a structure.
Tension pulls a material apart.
Compression pushes a material together.
Bending causes a material to curve under load.
Torsion twists a material.
Shear causes parts of a material to slide past each other.
A structure can fail if it is overloaded, poorly joined, made from unsuitable materials or designed with weak points.
Stress is the force acting on a material over a specific area.
Strain is the amount a material deforms when a force is applied.
Young’s modulus describes the stiffness of a material. A material with a high Young’s modulus is more rigid and resists deformation. A material with a lower Young’s modulus is more flexible.
Designers use this knowledge to select materials and forms that can safely handle expected loads.
Structural systems must be designed to resist forces safely while using suitable materials, shapes and joining methods.
What type of structure is being used: frame, shell, solid or combination?
What loads or forces will the product experience?
Is the structure mainly in tension, compression, bending, torsion or shear?
How does the shape of the structure improve strength or stability?
What material properties are important for this structure?
Where might the structure fail under load?
How could the structure be made stronger, lighter or more stable?
How could testing or FEA help evaluate the structure?
Tensile Stress & Strain, Compressive Stress & Shear Stress
Useful for understanding stress, strain and different ways forces act on materials.
https://www.youtube.com/watch?v=c6ndD5kTkP4
Understanding the Finite Element Method
Useful for HL students when linking structural testing to digital simulation and FEA.
https://www.youtube.com/watch?v=GHjopp47vvQ
HL only
Mechanical systems are designed to create, control or transfer movement and force. Designers use mechanical systems in products that need to move, rotate, lift, grip, push, pull or change direction.
A mechanical system usually includes parts that work together, such as levers, gears, pulleys, cams, linkages, springs, axles or bearings. Designers need to understand how these parts affect movement, speed, force, efficiency and user control.
Mechanical systems can create or transfer different types of motion.
Linear motion moves in a straight line.
Rotary motion moves around an axis.
Oscillating motion moves back and forth in an arc.
Reciprocating motion moves backwards and forwards in a straight line.
Designers may use mechanisms to change one type of motion into another. For example, a cam can convert rotary motion into reciprocating motion.
Levers help increase force or control movement around a pivot point.
Gears transfer rotary motion and can change speed, torque or direction.
Pulleys use wheels and belts or ropes to transfer force and movement.
Cams convert rotary motion into reciprocating or oscillating motion.
Linkages connect parts together to transfer or control movement.
Springs store and release energy.
Bearings reduce friction and help parts move smoothly.
Mechanical systems can make tasks easier by increasing force, changing direction or improving control. However, energy can be lost through friction, heat, poor alignment or unsuitable materials.
Designers aim to create mechanical systems that are reliable, efficient, safe and suitable for the intended user and product.
Mechanical systems help designers control movement and force within a product.
What type of motion is used in the product?
Does the mechanism change one type of motion into another?
What components are used: levers, gears, pulleys, cams or linkages?
How does the mechanism make the product easier to use?
Where might friction, wear or energy loss occur?
Is the mechanism safe and reliable for the intended user?
Could the mechanism be simplified or improved?
How might material choice affect the performance of the mechanism?
Types of Motion — GCSE Design and Technology
Useful for understanding linear, rotary, oscillating and reciprocating motion.
https://www.youtube.com/watch?v=Z7TqZVRp1xQ
Mechanisms: Levers, Gears, Pulleys, Cams and Linkages
Useful for introducing common mechanical systems used in product design.
https://www.youtube.com/watch?v=BrK8xgT0hEg
HL only
Electronic systems allow products to sense, process and respond to information. They are used in products such as automatic lights, smart watches, alarms, electronic toys, medical devices and smart home systems.
Most electronic systems can be understood using input, process and output.
Input
Input devices collect information from the user or environment. Examples include switches, light sensors, temperature sensors, pressure sensors, microphones and motion sensors.
Process
The process stage makes decisions based on the input. This could involve a simple circuit, logic gate, microcontroller or programmable device.
Output
Output devices respond to the processed information. Examples include LEDs, buzzers, motors, speakers, displays and actuators.
Open-loop systems produce an output without checking whether the desired result has been achieved. For example, a toaster may heat for a set time without checking the colour of the toast.
Closed-loop systems use feedback to monitor the output and adjust the system. For example, a thermostat measures the temperature and switches heating on or off to maintain a set temperature.
Analogue signals can vary continuously. For example, a temperature sensor may produce a range of values.
Digital signals use set values, usually on/off or 1/0. For example, a switch is either pressed or not pressed.
Designers need to understand these signals so they can choose suitable sensors, components and control systems.
Common electronic components include:
Sensors to detect changes in the environment.
Switches to control circuits manually.
Resistors to control current.
LEDs to give visual feedback.
Buzzers to give sound feedback.
Motors to create movement.
Microcontrollers to process inputs and control outputs.
Electronic systems allow products to sense, decide and respond.
What input, process and output devices are used?
Does the product use sensors, switches or feedback?
Is the system open-loop or closed-loop?
Are the signals analogue or digital?
How does the electronic system improve the product?
What output does the system create?
Could automation make the product safer, easier or more efficient?
What limitations could the electronic system have?
Aaron Thompson — Design Technology Topic 3.4 Part 1
Useful IB DT support video for electronic systems.
https://www.youtube.com/watch?v=AvE1MeXbQV8
Analogue and Digital Signals Explained
Useful for understanding the difference between analogue and digital signals.
https://www.youtube.com/watch?v=WxJKXGugfh8
Material selection is the process of choosing the most appropriate material for a product, component or prototype. Designers must consider how the material will perform, how it will be manufactured, how it will look and how it will affect the product’s life cycle.
A good material choice should be based on evidence, not just appearance or personal preference. The chosen material should match the product’s function, user needs, manufacturing process, cost, safety requirements and environmental context.
Function
The material must allow the product to work as intended. For example, a chair needs materials that can support weight safely.
Mechanical properties
Designers consider properties such as strength, stiffness, toughness, hardness, elasticity and ductility.
Physical properties
Designers may consider density, thermal conductivity, electrical conductivity, melting point and thermal expansion.
Chemical properties
The material may need corrosion resistance, food safety, low flammability or resistance to moisture.
Aesthetics
Colour, texture, finish and overall appearance can influence how users perceive the product.
Manufacturing process
Some materials are more suitable for specific processes, such as injection moulding, CNC machining, laser cutting, casting, forming or 3D printing.
Cost and availability
The material must be realistic for the intended scale of production and available within the project constraints.
Sustainability
Designers should consider whether the material is renewable, recycled, recyclable, biodegradable, repairable or suitable for a circular economy.
Designers often compare several possible materials before making a final choice. They may use material testing, product analysis, user needs, manufacturing constraints and environmental considerations to justify their decision.
For example, a product that needs to be lightweight, strong and weather-resistant may require a different material from a product that needs to be low-cost, biodegradable or easy to recycle.
Material selection involves balancing performance, manufacture, cost, appearance, safety and sustainability.
Why might this material have been chosen?
Does the material suit the product’s function?
What mechanical, physical or chemical properties are important?
Is the material suitable for the manufacturing process?
How does the material affect cost, durability or safety?
Does the material improve the user experience?
Could a different material improve performance or sustainability?
What trade-offs may the designer have made?
Material Properties GCSE DT
A useful Design & Technology video explaining how material properties influence material choice.
https://www.youtube.com/watch?v=dG6BTfS52HE
HL only
Structural systems are selected to help a product support loads, resist forces and remain stable during use. Designers must choose suitable structures based on the product’s function, user needs, material properties, safety requirements and manufacturing method.
A well-selected structural system should provide enough strength and stability without adding unnecessary weight, cost or material use.
Designers may use different structural systems depending on the purpose of the product.
Frame structures
Useful when a product needs to be strong but lightweight. Examples include bicycle frames, chair frames, shelving units and bridges.
Shell structures
Useful when a product needs an outer surface that protects, supports or contains something. Examples include helmets, bottles, packaging and car bodies.
Solid structures
Useful when strength, mass or stability is needed. Examples include concrete blocks, walls, bases and heavy-duty supports.
Combination structures
Many products use more than one structural system. For example, a chair may use a frame for support and a shell seat for comfort.
Designers need to consider:
Loads and forces
The structure must resist forces such as tension, compression, bending, torsion and shear.
Material properties
The chosen material must have suitable strength, stiffness, toughness, hardness or flexibility.
Safety
The structure should not fail during normal use and may require a suitable factor of safety.
Weight
The structure should be strong enough without being heavier than necessary.
Manufacture
The structure must be realistic to make using suitable processes, joints and components.
Cost and sustainability
Designers should avoid unnecessary material use and consider the product’s environmental impact.
Structural systems can be tested using physical prototypes, load testing, user testing or digital simulations such as FEA. Testing helps designers identify weak points, stress concentrations and areas that may need strengthening or redesigning.
Designers select structural systems by balancing strength, stability, weight, safety, manufacture, cost and sustainability.
What type of structural system has been used?
Why might this structure be suitable for the product?
What loads and forces will act on the product?
Where might the structure experience the most stress?
How does the structure provide strength or stability?
Is the structure lightweight, material-efficient or over-engineered?
What materials and joints are used in the structure?
How could testing or FEA help improve the structure?
Aaron Thompson — Design Technology Topic 3.2
Useful IB DT support video for structural systems and how structures behave under load.
https://www.youtube.com/watch?v=UEkHVLKYlaI
HL only
Mechanical systems are selected to create, control or transfer movement and force within a product. Designers choose mechanisms based on the product’s function, user needs, required motion, safety, reliability, efficiency and manufacturing method.
A suitable mechanical system should make the product easier to use, more effective or more controlled.
Designers may use different mechanical systems depending on the task.
Levers
Useful for increasing force or improving control. Examples include scissors, bottle openers, pliers and brake handles.
Gears
Useful for transferring rotary motion and changing speed, torque or direction. Examples include bicycles, hand drills, clocks and gearboxes.
Pulleys
Useful for lifting loads or transferring movement using belts or ropes. Examples include cranes, blinds, gym machines and elevators.
Cams
Useful for converting rotary motion into reciprocating or oscillating motion. Examples include toys, engines and mechanical automata.
Linkages
Useful for connecting parts and controlling movement. Examples include folding chairs, windscreen wipers and mechanical grabbers.
Springs
Useful for storing and releasing energy. Examples include pens, clips, suspension systems and door mechanisms.
Designers need to consider:
Type of motion
The system may need linear, rotary, reciprocating or oscillating motion.
Force and mechanical advantage
The mechanism may need to increase force, reduce effort or make a task easier for the user.
Speed and torque
Some systems need more speed, while others need more turning force.
Efficiency
Friction, poor alignment and unsuitable materials can reduce performance.
Safety and reliability
Moving parts must be safe, durable and suitable for repeated use.
Manufacture and maintenance
The mechanism should be realistic to produce, assemble, repair and maintain.
Mechanical systems can be tested using physical prototypes, CAD motion studies, user testing and performance testing. Designers may check movement, strength, effort, speed, reliability, wear, friction and ease of use.
Designers select mechanical systems by balancing motion, force, efficiency, safety, reliability, manufacture and user needs.
What type of motion does the product use?
What mechanism has been selected and why?
Does the system change one type of motion into another?
Does the mechanism increase force, speed or control?
Where might friction, wear or failure occur?
Is the mechanism safe and reliable for repeated use?
How does the mechanism improve the user experience?
Could a different mechanism improve the product?
Aaron Thompson — Design Technology Topic 3.3
Useful IB DT support video for mechanical systems, including motion and mechanisms.
https://www.youtube.com/watch?v=55fr7A6FGqc
HL only
Electronic systems are selected to help products sense information, process it and produce a useful response. Designers choose electronic systems based on the product’s function, user needs, environment, safety, reliability, cost and power requirements.
A suitable electronic system should make the product more effective, easier to use, safer or more responsive.
Designers may use different electronic systems depending on what the product needs to do.
Sensors
Sensors detect changes in the environment or user input. Examples include light sensors, temperature sensors, pressure sensors, motion sensors and moisture sensors.
Switches
Switches allow users to control a circuit manually. Examples include push buttons, toggle switches and limit switches.
Microcontrollers
Microcontrollers process inputs and control outputs. They are useful when a product needs programmed behaviour, timing, feedback or automation.
Outputs
Outputs produce a response. Examples include LEDs, buzzers, displays, motors, speakers, solenoids and actuators.
Feedback systems
Feedback systems monitor the output and adjust the system. For example, a thermostat uses temperature feedback to control heating.
Designers need to consider:
Function
The system must perform the required task accurately and consistently.
User needs
Controls, displays and feedback should be easy for the intended user to understand and operate.
Environment
Components must suit the conditions of use, such as moisture, heat, dust, impact or outdoor exposure.
Power supply
The product may need batteries, mains power, rechargeable cells or renewable energy sources.
Safety and reliability
The system should be safe, durable and dependable during repeated use.
Cost and manufacture
Components should be realistic for the intended scale of production and assembly method.
Electronic systems can be tested using breadboards, simulations, prototypes and user testing. Designers may check whether sensors respond correctly, outputs work as intended, power use is suitable and the system is reliable in its intended environment.
Designers select electronic systems by balancing function, user needs, reliability, safety, power, cost and environment.
What input, process and output devices are used?
Why might these components have been selected?
Does the system need sensors, switches, feedback or automation?
Is the system open-loop or closed-loop?
What power source is most suitable?
Is the system safe and reliable for the intended environment?
How does the electronic system improve the user experience?
Could a different electronic system improve the product?
Aaron Thompson — Design Technology Topic 3.4 Part 1
Useful IB DT support video for electronic systems.
https://www.youtube.com/watch?v=AvE1MeXbQV8
Product analysis and evaluation help designers understand how well an existing product meets user needs and performs in its intended context. Designers study products to identify strengths, weaknesses and opportunities for improvement.
Product analysis usually looks at features such as function, materials, ergonomics, aesthetics, safety, manufacture, cost and sustainability. Evaluation involves making a judgement about how successful the product is, using evidence rather than opinion.
Designers may analyse products to understand:
Function
What does the product do, and how well does it perform its main purpose?
User needs
Does the product suit the intended user’s needs, abilities and context?
Ergonomics
Is the product comfortable, safe and easy to use?
Materials and components
Are the materials and parts suitable for the product’s function, durability and manufacture?
Manufacture
How might the product have been made, assembled and finished?
Aesthetics
How do form, colour, texture and finish affect the product’s appeal?
Sustainability
Does the product consider repair, reuse, recycling, material choice or end-of-life impact?
Evaluation goes beyond describing the product. Designers should judge how successful the product is and support their points with evidence.
This evidence may come from user feedback, product testing, measurements, comparison with similar products, research findings or a design specification.
Product analysis identifies how a product works and why it has been designed that way. Evaluation judges how successful it is using evidence.
What is the product designed to do?
Who is the intended user?
How well does the product meet the user’s needs?
What materials and components have been used?
Are the materials suitable for the product’s function?
How does the product support comfort, safety and ease of use?
What manufacturing methods may have been used?
How sustainable is the product across its life cycle?
What improvements could be made and why?
Aaron Thompson — Product Analysis
Useful IB DT support video for analysing products and understanding how design decisions affect performance.
https://www.youtube.com/watch?v=wRmLv5WJ31g
HL only
Life-cycle analysis, or LCA, is used to evaluate the environmental impact of a product across its whole life. This includes the materials used, how the product is manufactured, transported, used, maintained and disposed of at the end of its life.
Designers use life-cycle analysis to identify where the greatest environmental impact occurs and how the product could be improved. It helps designers make more responsible decisions about materials, manufacturing, energy use, packaging, repair, recycling and disposal.
Raw materials
The extraction, farming or production of materials needed to make the product. Designers should consider whether materials are renewable, recycled, recyclable or responsibly sourced.
Manufacture
The processes used to shape, form, join and finish the product. Some processes use more energy, create more waste or produce more pollution than others.
Distribution
The transport, packaging and storage of the product. Designers may reduce impact by lowering weight, reducing packaging or using local suppliers.
Use
The energy, water, consumables, maintenance or repairs needed while the product is being used.
End of life
What happens when the product is no longer needed. It may be repaired, reused, upgraded, recycled, composted, incinerated or sent to landfill.
Life-cycle analysis helps designers compare design choices and reduce environmental impact. For example, a product may use sustainable materials but still have a high impact if it needs a lot of energy during use or is difficult to repair.
LCA encourages designers to look beyond one stage and consider the full system.
Life-cycle analysis helps designers evaluate the environmental impact of a product from raw materials to end of life.
What stages of the product’s life cycle create the most impact?
Where do the raw materials come from?
How much energy or waste may be involved in manufacture?
How is the product packaged and transported?
Does the product use energy, water or consumables during use?
Can the product be repaired, reused, upgraded or recycled?
What happens to the product at the end of its life?
How could the product’s life cycle impact be reduced?
Life Cycle Assessment Explained
Useful for understanding how environmental impact can be considered across a product’s full life cycle.
https://www.youtube.com/watch?v=2Jzw2H1mKcg