France Quatrième Technology
Chapters: 3
1. Design and innovation
Needs, constraints, specifications · Sketches and 3D modelling
- The Design Process: From Problem to Product – The design process is a loop of steps designers use to solve a real problem for real people: investigate the need, define it in a brief and a measurable specification, generate many ideas, build a prototype, then test and evaluate it against the specification. Whatever fails sends you back round the loop. This repeating is called iteration, and it is how almost every product, app, building and artwork is improved.
- CAD Modelling: From a Sketch to a 3D Part – CAD (computer-aided design) means using a computer to draw and build exact models of objects before they are made. A design starts as a freehand sketch. In CAD it becomes a 2D sketch with constraints and dimensions. 3D tools such as extrude, revolve and cut turn the sketch into a solid. Each step is saved in a feature tree, so changing one size rebuilds the whole model. Parts are joined in assemblies, tested by simulation, shared as drawings and sent to 3D printers, laser cutters or CNC machines.
2. Technical objects and systems
Energy chain and information chain · Materials and their properties
- Systems Engineering – Systems engineering designs a product as a whole system. It starts from the user's need, turns it into measurable requirements, follows the flows of matter, energy and information through the parts, and checks the result on the way back up the V-cycle: verify (built right?) and validate (right thing?).
- Materials and Their Properties: Why Things Are Made of What They Are – Every product is made from materials chosen for their properties. The main families are papers and boards, timbers, metals, polymers (plastics) and textiles. Physical properties describe what a material is like (density, conductivity, how it reacts to heat and water). Working properties describe how it behaves when we use or shape it (strength, hardness, toughness, elasticity, plasticity, malleability, ductility). Materials come from natural sources such as trees, ores and crude oil, and are sold in standard stock forms like sheets, bars, tubes and planks. A designer picks a material by matching its properties to the job, and also thinks about cost, availability, looks and the environment.
3. Computing and programming
Networks and data transmission · Programming an automated system
- Computer Networks and How the Internet Works – A network is a group of devices linked to share data. Each device has an IP address. Data is cut into numbered packets. Routers pass each packet hop by hop towards its address, and TCP puts the packets back in order. DNS turns a website name into an IP address. Clients ask, servers answer. Firewalls, passwords, updates and encryption keep a network safe.
- How Networks Grew and How Data Travels – A computer network is a group of connected devices that share data. Networking began with ARPANET (1969), grew into NSFNET (1980s) for universities, and joined with other networks to become the Internet, a network of networks. Every data communication has five parts: sender, receiver, message, communication media and protocol. Bandwidth is the range of frequencies a channel can carry (in Hz); data rate is how many bits travel per second (bps). Every device on a network has an IP address. Data can move by circuit switching (a fixed path is booked first) or packet switching (data is cut into packets that travel on their own).
- Block Programming: Algorithms, Loops, Variables, Events and Sensors – In block programming you snap coloured blocks together to build a program. An algorithm is the plan; the program is the plan written in blocks. Loops repeat blocks, variables store changing values, conditions choose between actions, events start the program, and sensors feed the robot facts about the world. Custom blocks (subprograms) give a name to a group of blocks so you can reuse it.