GCSE Design & Technology Knowledge Organiser

Materials Knowledge - Woods, Plastics, Metals & Composites

Ever wondered why your school chair is made from polypropylene rather than oak? Understanding material properties is crucial for picking the right stuff for the job.

Hardwoods like oak and beech come from deciduous trees and are brilliant for furniture because they're strong and look good. Softwoods like pine are cheaper and perfect for construction work. Man-made boards like MDF and chipboard give you the benefits of wood without the high cost - they're made from wood chips and glue, so they're consistent and easy to work with.

Plastics fall into two camps: thermoplastics (like acrylic and polypropylene) that can be reheated and reshaped, and thermosetting plastics (like urea formaldehyde) that set permanently once heated. Metals are either ferrous (contain iron and rust) or non-ferrous (don't contain iron, won't rust).

Quick Test Tip: Remember that material properties like strength, elasticity, and hardness determine what each material is good for. A tough material won't shatter under impact, whilst a ductile one can be stretched without breaking.

Composite materials like carbon fibre combine different materials to get the best of both worlds - carbon fibre is incredibly strong yet lightweight, which is why it's used in sports cars and high-end equipment.

Joining Methods, Production & Tools

Knowing how to stick things together properly can make or break your project! Wood joints are either permanent (like using PVA glue) or temporary (like screws that you can undo later).

Scales of production matter loads for your exam. One-off means making something unique, batch production is making a set amount, mass production churns out thousands, and continuous production never stops. Each scale uses different techniques and costs.

Surface finishes aren't just about looking pretty - they protect your material too. Paint, varnish, oil, and wax all do different jobs. Danish oil soaks into wood to protect it from inside, whilst paint creates a protective barrier on top.

Exam Success: Learn the difference between CAD (Computer Aided Design), CAM (Computer Aided Manufacture), and CNC (Computer Numerical Control) - they're exam favourites!

Adhesives have specific jobs: PVA is perfect for wood, epoxy bonds most materials, and contact adhesive creates that tacky bond you need for laminates. Pick the wrong glue and your project falls apart!

Paper & Board Materials

Paper and board might seem simple, but there's actually loads to know for your GCSE! Everything's measured in GSM (grams per square metre) - the higher the number, the thicker and stronger your material.

Paper sizes follow a logical pattern from A0 (biggest) down to A7 (smallest), with each size being exactly half the previous one. A4 is your standard size that you use every day. Microns measure thickness - 1000 microns equals 1mm.

Different papers do different jobs. Layout paper is lightweight for initial sketches, cartridge paper is your general-purpose workhorse, and tracing paper lets you copy drawings. For boards, corrugated card gives strength with lightness, whilst foam core board is brilliant for precise model-making.

Material Selection Pro Tip: Always consider functionality, cost, availability, and environmental impact when choosing materials. The FSC (Forest Stewardship Council) mark means your paper comes from sustainable sources.

When selecting materials, think about aesthetics (how it looks), functionality (does it do the job), and environmental factors (can it be recycled). Social and cultural factors matter too - some materials might not be appropriate in certain contexts.

Fabric Technology

Fabrics are everywhere in design technology, from school uniforms to car interiors! Natural fabrics like cotton, wool, and silk come from plants or animals, whilst synthetic fabrics like polyester and nylon are manufactured.

Cotton is brilliant because it's soft, breathable, and machine washable - perfect for everyday clothes. Wool gives you natural insulation and fire resistance. Polyester won't wrinkle and resists stains, which is why it's in school shirts. Blended fabrics mix natural and synthetic to get the best properties.

Fabric construction affects how the material behaves. Woven fabrics using plain or twill weave are strong and hard-wearing. Knitted fabrics are stretchy and comfortable. Non-woven fabrics like felt are held together with glue or stitching rather than weaving.

Care Label Hack: Those symbols aren't random! The number tells you maximum washing temperature, and more dots on the iron symbol means higher heat settings.

Understanding fabric properties helps you pick the right material. If you need stretch, go for knitted or add elastane. Need durability? Choose a tightly woven fabric. Want easy care? Pick synthetic or blended fibres.

Construction & Decorative Techniques

Getting your construction techniques right makes the difference between a product that falls apart and one that lasts for years! Seams are your basic joining method - open seams are standard, French seams work for delicate fabrics, and flat fell seams give extra strength for heavy-duty items like jeans.

Decorative techniques aren't just about looks - they add value and personalisation to products. Appliqué involves attaching fabric pieces, whilst embroidery creates patterns with stitching. Heat transfer lets you add designs quickly, and batik uses wax to create unique patterns.

Pattern making is crucial for accurate construction. Your seam allowance (usually 1cm) gives you room to sew properly. Always mark the right side (the side you want to see) and wrong side of your fabric before cutting.

Technical Accuracy Tip: 'Pressing' isn't the same as ironing! Pressing means lifting the iron up and down to flatten seams, whilst ironing involves sliding the iron along the fabric.

Equipment knowledge is essential. Fabric shears cut cleanly through material, pinking shears prevent fraying, and a quick unpick fixes mistakes safely. Understanding your tools prevents accidents and improves your results.

CAD/CAM & Production Systems

Computer Aided Design (CAD) has revolutionised how we create products. You can save, edit, and share designs instantly, plus test them virtually before making anything. The downside? Software's expensive and takes time to learn properly.

Computer Aided Manufacturing (CAM) speeds up production massively and ensures every part is identical. Laser cutters, robots, and CNC machines work 24/7 without getting tired. But if they break down, production stops completely, and you need skilled technicians to fix them.

Flexible Manufacturing Systems (FMS) let you switch between different products quickly - perfect for batch production. Lean manufacturing eliminates waste in all its forms: overproduction, waiting time, unnecessary transport, and defects.

Production Strategy: Just In Time (JIT) sounds brilliant - no storage costs and fresh stock - but you're completely reliant on suppliers never letting you down!

Product lifecycle thinking considers environmental impact from raw materials through manufacturing, use, and disposal. Planned obsolescence deliberately designs products to fail after a set time, which keeps sales going but creates environmental problems.

Mechanical Devices & Motion

Understanding how things move is fundamental to designing products that actually work! There are four types of motion: linear (straight line), rotary (circular), reciprocating (back and forth), and oscillating (side to side along a curved path).

Levers are everywhere once you start looking. Class one levers (like scissors) have the fulcrum between input and output. Class two levers (like wheelbarrows) have the load between fulcrum and effort. Class three levers (like tweezers) have the effort between fulcrum and load.

Linkages change motion direction brilliantly. Reverse motion linkages flip the direction completely - pull one end, the other pushes. Parallel motion linkages keep everything moving in the same direction. Bell crank linkages change horizontal motion to vertical or vice versa.

Mechanical Advantage Magic: If your input arm is 400mm and output arm is 100mm, you get a 4:1 mechanical advantage - four times the force but quarter the distance!

Calculating mechanical advantage is straightforward: divide the load by the effort. If you're lifting 300N with 100N of effort, that's a 3:1 advantage. Remember, you gain force but lose distance!

Forces, Stresses & Material Improvement

Understanding forces and stresses helps you design products that won't break when people actually use them! Different forces attack materials in different ways, so you need to test each one properly.

Tension tries to pull materials apart, compression squashes them, torsion twists them, and shear forces try to slide parts past each other. Bending combines tension and compression forces, which is why beams often fail at the edges where stress concentrates.

Fair testing means using the same conditions for every material - same weight, same support method, same environment. This gives you reliable data for comparison and helps you pick the right material for each job.

Smart Material Hacks: You can improve materials by reinforcing them - concrete gets steel bars for extra strength, whilst composite materials combine different properties for the best of both worlds.

Material testing in school might use simple equipment, but the principles are the same as professional engineering. Understanding how materials behave under stress helps you design products that are safe, reliable, and fit for purpose.

Energy Sources & Systems

Energy powers everything we make and use! Fossil fuels (coal, oil, gas) are non-renewable - once they're gone, they're gone. They work by burning fuel to create heat, which makes steam, which turns turbines, which generate electricity.

Renewable energy sources won't run out in our lifetime. Wind energy uses moving air to turn turbines directly. Solar energy converts sunlight to electricity using photovoltaic cells. Hydroelectricity uses falling water to turn turbines, whilst tidal energy harnesses the sea's movement.

Nuclear energy is controversial - it produces loads of electricity without carbon emissions, but creates radioactive waste that lasts thousands of years. Biomass energy burns organic matter like wood, which is renewable if you replant trees faster than you cut them down.

Battery Basics: Alkaline batteries are cheap but bad for the environment. Rechargeable batteries cost more upfront but last longer and create less waste - much better for the planet!

Energy transformation happens at every stage. Chemical energy in fuel becomes heat energy in burning, then kinetic energy in turbines, finally electrical energy from generators. Understanding these transformations helps you design more efficient systems.

The 6 R's & Sustainability

The 6 R's hierarchy shows the best ways to reduce environmental impact, starting with the most effective. Refuse is top - simply not buying or using something saves 100% of its environmental cost.

Rethink means questioning your choices and looking for better alternatives. Reduce cuts down on materials and energy through clever design and efficient manufacturing. These three R's prevent waste rather than dealing with it afterwards.

Reuse extends product life by using items multiple times, either for the same purpose or something completely different. Repair fixes broken products instead of replacing them, but many modern products are designed to be unrepairable - that's planned obsolescence.

Sustainability Success: Finite resources (like oil and metals) will eventually run out, whilst non-finite resources (like sunlight and wind) keep going indefinitely. Design with this in mind!

Recycle is important but comes last because it still uses energy and often produces lower-quality materials. Recyclable materials need to be sorted carefully, and some materials can only be recycled a few times before they're unusable.

Understanding sustainability helps you make better design decisions that consider environmental impact alongside cost and performance.