KS3 Design and Technology key terms

135 terms with short definitions you can learn for the exam. Type to filter the list.

Key terms glossary 112

6 Rs: Reduce, Reuse, Recycle, Rethink, Refuse and Repair: ways to reduce a product's harm to the environment.
ACCESS FM: A checklist for specifications and product analysis: Aesthetics, Cost, Customer, Environment, Size, Safety, Function, Materials.
Actuator: An output component that makes something move, such as a motor, servo or solenoid.
Aesthetics: How a product looks, feels, sounds or smells, and how attractive it is to the user.
Alloy: A mixture of a metal with one or more other elements, made to improve its properties, such as brass or steel.
Annotation: Notes added to a sketch to explain a design: materials, sizes, how it works and why choices were made.
Anthropometrics: The study of human body measurements, such as height and hand length, used to size products.
Batch production: Making a set number of identical products together, then moving on to the next batch.
Bell crank: A linkage that changes the direction of motion through 90°.
Bevel gears: Gears with angled teeth that turn rotary motion through 90°.
Biomimicry: Designing by copying ideas from nature, such as Velcro, which was inspired by plant burrs.
Brittle: Breaks or shatters easily without bending. The opposite of tough.
CAD: Computer-aided design: using software to design products in 2D or 3D.
CAM: Computer-aided manufacture: using computer-controlled machines, such as laser cutters, to make products.
Cam: A shaped part on a rotating shaft that moves a follower, changing rotary motion into reciprocating motion.
Caramelisation: The browning of sugar when it is heated.
Circular economy: Keeping products and materials in use for as long as possible, then recycling them, instead of throwing them away.
CNC: Computer numerical control: machines controlled by numerical data from a computer.
Coagulation: The setting of proteins when they are heated, such as an egg becoming solid.
Composite: A material made by combining two or more different materials, such as reinforced concrete or carbon fibre.
Compression: A force that pushes or squashes.
Conduction: Heat passing through a solid, such as from a pan into food.
Convection: Heat carried by currents in a liquid or gas, such as in boiling water or a fan oven.
Corrugated card: Card with a wavy (fluted) middle layer, making it strong, light and cushioning.
Crating: Drawing a box first and then drawing the object inside it.
Cross-contamination: The spread of bacteria from one food, surface or object to another, such as from raw meat to salad.
Deciduous: Trees that usually lose their leaves in winter. Hardwoods come from broad-leaved trees, most of which are deciduous.
Density: How much mass is packed into a volume: mass ÷ volume.
Design brief: A short statement of the design problem, who it is for and where it will be used.
Dextrinisation: The browning of starch with dry heat, as in toast.
Ductility: The ability to be stretched into a thin wire, like copper.
Dwell: The part of a cam's turn when the follower stays still.
Eatwell Guide: The UK government's guide showing the proportions of each food group in a healthy, balanced diet.
Elasticity: The ability to return to the original shape after being stretched or bent.
Ergonomics: Designing products to fit the people who use them, so they are comfortable, safe and efficient.
Evaluation: Judging how well a product meets its specification and the user's needs, using evidence.
Exploded view: A drawing showing the parts of a product pulled apart along the lines in which they fit together.
Ferrous metal: A metal that contains iron, such as mild steel or cast iron. Most rust and are magnetic.
Finite resource: A resource that will run out because it cannot be replaced, such as crude oil.
Food miles: The distance food travels from where it is produced to where it is eaten.
Fulcrum: The pivot point that a lever turns about.
Gear ratio: Teeth on the driven gear ÷ teeth on the driver gear.
Gelatinisation: Starch grains absorbing liquid, swelling and bursting when heated, which thickens sauces.
gsm: Grams per square metre: the unit used for the weight of paper and card.
Hardness: The ability to resist scratching, wear and denting.
Hardwood: Wood from broad-leaved trees, usually deciduous, such as oak, beech and balsa.
Hazard: Something that could cause harm.
Idler gear: A gear placed between the driver and driven gears so they turn the same way.
Isometric drawing: A 3D drawing where vertical lines stay vertical and horizontal lines are drawn at 30°.
Iterative design: Designing in a repeated loop of exploring, creating, testing and improving.
Jig: A device that holds work or guides a tool so an operation is repeated accurately.
LDR: Light-dependent resistor: an input sensor whose resistance falls as light gets brighter.
LED: Light-emitting diode: an output that gives light and only lets current flow one way.
Lever: A rigid bar that turns about a pivot (fulcrum), used to change the size or direction of a force.
Life cycle assessment: A study of a product's environmental impact from raw materials, through making, transport and use, to disposal.
Linkage: Levers joined by pivots to change the direction or size of movement.
Macronutrients: Nutrients needed in large amounts: protein, carbohydrate and fat.
Malleability: The ability to be hammered, pressed or rolled into shape without cracking.
Manufactured board: A sheet material made by gluing wood layers, chips or fibres, such as MDF, plywood and chipboard.
Mass production: Making very large numbers of identical products, usually on a production line.
MDF: Medium density fibreboard: wood fibres and resin pressed into smooth, flat sheets.
Mechanical advantage: Load ÷ effort. It shows how much a mechanism multiplies the force you put in.
Microcontroller: A small programmable computer on a single chip, used to control products.
Micronutrients: Nutrients needed in small amounts: vitamins and minerals.
Modern material: A material developed through new technology with improved properties, such as graphene or Kevlar.
Mould: A hollow shape that material is formed in to give it a shape.
Non-ferrous metal: A metal that contains no iron, such as aluminium, copper and zinc.
Oblique drawing: A 3D drawing with the front face drawn flat and true shape, and depth lines going back at 45°.
Orthographic projection: A technical drawing showing separate 2D views (front, plan and end) with exact sizes.
Oscillating motion: Swinging backwards and forwards in an arc, like a pendulum.
Percentile: A value that shows the percentage of people below it. 5% of people are smaller than the 5th percentile.
Planned obsolescence: Designing a product to go out of date or stop working after a time, so people replace it.
Plasticity: The ability to change shape permanently without breaking.
Plywood: A manufactured board of thin wood layers glued with the grain of each layer at 90° to the next.
Primary processing: Turning raw food into something that can be eaten or used to make other foods, such as milling wheat into flour.
Primary research: Information you collect yourself, such as questionnaires, interviews and observation.
Product analysis: Investigating an existing product to learn how and why it was designed and made.
Prototype: An early working version of a product, used to test a design.
Quality control: Checking products or parts during manufacture to find faults.
Rack and pinion: A gear system that changes rotary motion into linear motion.
Radiation: Heat travelling as infrared waves straight onto food, as under a grill.
Raising agent: Something that adds gas to a mixture to make it rise, such as air, baking powder, yeast or steam.
Reciprocating motion: Moving backwards and forwards in a straight line.
Rendering: Adding colour, tone and texture to a drawing to make it look realistic.
Resistor: A component that limits the current in a circuit. Its value is measured in ohms (Ω).
Risk assessment: A record of the hazards in a task, who could be harmed and the control measures that reduce the risk.
Rotary motion: Turning round in a circle, like a wheel.
Seasonal food: Food eaten at the time of year when it is naturally harvested where you live.
Secondary processing: Turning primary-processed food into other products, such as flour into bread.
Secondary research: Information already collected by other people, such as books, websites and reports.
Sensor: An input component that responds to a change, such as light, temperature or pressure.
Shear: Forces acting in opposite directions across a part, trying to slide it apart, as when scissors cut.
Smart material: A material that changes a property in response to a change in its surroundings, such as heat or light.
Softwood: Wood from coniferous trees, which have needles and cones, such as pine and cedar.
Specification: A list of measurable requirements that a product must meet.
Stakeholder: Anyone affected by a product, such as users, buyers and makers.
Strut: A part of a frame structure that is in compression.
Sustainability: Meeting our needs without stopping future generations from meeting theirs.
Template: A shape you draw round or cut round to copy an outline accurately.
Tension: A force that pulls or stretches.
Thermistor: An input sensor whose resistance changes with temperature. In the common type it falls as temperature rises.
Thermochromic: Changes colour with temperature.
Thermoplastic: A polymer that softens when heated and can be reshaped many times, such as acrylic.
Thermoset: A polymer that sets permanently after one chemical change and will not soften when reheated.
Tie: A part of a frame structure that is in tension.
Tolerance: The allowed range of sizes for a part, such as 60 mm ± 0.5 mm.
Torsion: A twisting force.
Toughness: The ability to absorb impacts without breaking or cracking.
Triangulation: Using triangles to make a frame rigid.
Use-by date: The date after which food may not be safe to eat. It is about safety.
User-centred design: Involving users and their needs at every stage of designing.
Velocity ratio: For pulleys, driven diameter ÷ driver diameter.

Formulas and facts to know 23

14 allergens: UK food law lists 14 major allergens that must be declared, including milk, eggs, peanuts, tree nuts, fish and sesame.
5 A DAY: Eat at least 5 portions of fruit and vegetables a day. A portion of fresh fruit or vegetables is 80 g.
5th to 95th percentile: Designing for this range covers 90% of people.
A sizes: A4 is 210 × 297 mm; A3 is 297 × 420 mm. Each size is half the one before.
Boiling point: Water boils at 100°C at sea level.
Density: Density = mass ÷ volume, for example in g/cm³.
Drawing angles: Isometric: horizontal edges at 30°. Oblique: depth lines at 45°, often drawn half length (cabinet oblique).
Energy in food: About 4 kcal per gram of carbohydrate or protein, and about 9 kcal per gram of fat.
Fibre: Adults should aim for 30 g of fibre a day.
Fish: Eat at least 2 portions of fish a week, one of them oily.
Fluid: Drink 6 to 8 cups or glasses of fluid a day. Limit fruit juice and smoothies to 150 ml a day in total.
Fridge temperature: Keep your fridge at 5°C or below.
Gear ratio: Gear ratio = teeth on driven gear ÷ teeth on driver gear. Output speed = input speed ÷ gear ratio.
Manufactured board sheets: Usually supplied in sheets of 2440 mm × 1220 mm.
Mechanical advantage: Mechanical advantage = load ÷ effort.
Ohm's law: Voltage (V) = current (I) × resistance (R). So R = V ÷ I.
Principle of moments: For a balanced lever: effort × distance from fulcrum = load × distance from fulcrum.
Resistor colour code: Black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. Bands: digit, digit, number of zeros.
Salt and sugar: No more than 6 g of salt and 30 g of free sugars a day for adults and children aged 11 and over.
Scale: 1:2 means the drawing is half the real size; 2:1 means it is twice the real size.
The 4Cs: Cleaning, Cooking, Chilling and Cross-contamination: the Food Standards Agency's keys to food hygiene.
Tolerance: Size ± tolerance gives the allowed range: 60 ± 0.5 mm means 59.5 mm to 60.5 mm.
Velocity ratio (pulleys): Velocity ratio = driven pulley diameter ÷ driver pulley diameter.

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