A

Accelerator One of the pedals at a vehicle driver’s feet. It changes the car’s speed by controlling the amount of fuel that enters the engine. In the US it is called the gas pedal. A different kind of accelerator is used in research to speed up particles like atoms.

Aerofoil The shape of an aircraft’s wing. The wing is curved on its upper side so that, as the plane moves, the air flowing over the wing is made to move faster than that flowing under it. This creates lower pressure on the upper side than on the lower side. An upward force, called lift, is the result.

Ailerons Flaps on the wings of an aeroplane. They can be raised or lowered in order to make the plane roll to one side or the other. This steers the aircraft.

Aircraft carrier A large military ship. Its main deck is a runway from which aircraft take off and land. Aircraft are kept in hangars below deck.

Airliner A large passenger-carrying aeroplane.

Airship A long balloon whose flight is controlled by engines and steered by a rudder. It is filled with lighter-than-air gases such as helium. Airships were used for passenger flights until the 1940s.

Algorithm A set of mathematical rules that enable a computer to calculate an answer to a problem automatically without a person getting involved. Music apps, for example, use algorithms to predict whether a fan of one band will like another.

Amplitude The strength of a wave, such as a radio wave.

Analogue see Electronic signal

App Short for mobile application software. Apps run on smartphones and tablet computers.

Astronaut A person who travels into space. In Russia, astronauts are known as cosmonauts. In China they are known as taikonauts.

Autopilot An automatic flight control system. It constantly adjusts a plane’s controls so that it keeps to the course, speed and altitude set by the pilot.

B

Ballast tank A compartment low in the hull of a ship or submarine that can be filled with water or air. In a submarine, ballast tanks are filled with water to make it dive, or filled with air to make it surface.

Beam A horizontal part of a building’s structure. It is made of steel, wood or reinforced concrete.

Booster rocket A rocket attached to a larger rocket to increase thrust. When its fuel runs out, it detaches from the rocket and parachutes back to Earth.

Bow The front part of a ship.

Brick A block of hardened clay or other hard materials used to construct some buildings.

Bridge (of a ship) A room high up in the ship, from where members of the crew control the ship.

Broadband A high-speed communications link along which many streams of digital information can pass at once. Broadband internet provides fast download speeds.

Broadcasting The transmission of radio and TV programmes to many receivers via cables, transmitters, satellites or the internet.

Bulldozer A vehicle used to move rubble and other waste, demolish old buildings and clear areas for new ones. At a bulldozer's front is a large metal shovel. This is used to scoop up rubble or earth and push it aside.

Byte A binary number (that is, made of nothing but ones and zeroes—these are called bits) in the form of a digital code that contains eight bits. Text, images, sounds or video can be stored on a computer in the form of a series of bytes.

C

Cabin The part of an aircraft, ship or other vehicle inside which passengers travel.

Cable television TV signals that are transmitted through a network of underground cables.

Cable-stayed bridge A bridge held up by steel cables. The cables are fixed to the tops of towers sunk into the ground. The weight of the bridge is supported by the towers.

Carrier wave A radio wave that can be modulated (changed using an electrical signal) in order to carry information. Once modulated, the radio wave is sent from a transmitter.

Catamaran A boat with two hulls, connected by one or more decks. Some catamarans are fitted with sails and used for racing. Larger models have diesel engines and are used as high-speed ferries.

Caterpillar tracks Metal belts used instead of wheels on heavy vehicles such as diggers or bulldozers. They spread the weight of the machines, enabling them to move over soft or uneven ground without getting stuck.

Central processing unit (CPU) The main part of a computer, which carries out instructions from a computer program. It acts as the computer’s “brain”.

Cement A powder that goes hard—after a while—when mixed with water. Cement is mixed with sand and water to make mortar for bricklaying. It is mixed with sand, water and aggregate to make concrete.

Cockpit The part of an aeroplane near its nose, where the pilot or pilots sit and where the control systems are located. The cockpit on an airliner is called the flight deck.

Combustion chamber The part of an engine of a car, plane, rocket or other vehicle in which air is mixed with fuel and ignited.

Compressor A device which squeezes air or other gases to compress them (make them fit into a smaller space). A compressor is used in a jet engine that compresses air. It consists of spinning blades that squeeze air into increasingly smaller spaces. The compressor then feeds this air through to the combustion chamber.

Computer An electronic machine that can be programmed (fed with instructions) to carry out large numbers of calculations automatically.​​​​​​​ Computers store information—numbers, words, sounds and pictures—in digital form. Personal computers (PCs), tablets or laptops are found in many homes and offices. Other types of computer are built into smartphones, domestic appliances like washing machines, vehicles and other machines. 

Concrete A building material made by mixing aggregate (sand or crushed rock), cement and water. Concrete sets to form a strong, stone-like material. Reinforced concrete has steel bars or wires embedded in it to make it much stronger.

Container ship A ship that carries cargo in large metal boxes called containers. These are loaded and unloaded using cranes, or rolled on and off in port.

Crane A tall machine used to lift building materials, such as steel beams. Some cranes are fixed to the ground, some are fixed to lorries and some can “creep” up the side of buildings as they are built.

Crankshaft A device that turns the up-and-down movement of pistons into rotating motion. It is used to turn the wheels of the car via a set of gears.

Cylinder A part in an engine inside which pistons move up and down.

D

Dam A barrier built across a river to hold water back, sometimes used to create a reservoir. The stored water may be used for homes and offices, watering crops or controlling flooding. Electricity can be generated by allowing the water to rush out through the dam and drive a turbine. This is called hydro-electric power.

Diesel engine A type of internal combustion engine that uses heat, rather than a spark, to ignite its fuel of diesel oil.

Diesel-electric locomotive A train in which the wheels are driven by electric motors, but the electricity is generated by a diesel engine.

Digger A construction vehicle used to scoop holes in the ground using a toothed metal shovel at its front.

Digital information Information that is stored as binary numbers (1 or 0). In a digital circuit, the current can only have two strengths—on and off. Turning information into digital form, which is necessary before it can be handled by an electronic circuit, is called digitization.

Download To transfer information—numbers, words, sounds or pictures—from another computer to the one being used. This is often done via the internet.

Drone Another name for an unmanned aerial vehicle (UAV). It is a robotic aircraft without a human pilot aboard. It may operate either under remote control by a human controller, or by itself, using onboard computers.

E

Electric car A car fitted with batteries that power an electric motor. It is “refuelled” by recharging its batteries.

Electric locomotive A train in which the wheels are turned by electric motors, usually one for each pair of wheels. Electricity is provided by overhead cables or an electrified third rail.

Electronic circuit An electric circuit made up of electronic components. By combining different components in different ways, it is possible to do many tasks.

Electronic component A basic part of an electronic circuit, such as a resistor, transistor or a light-emitting diode (LED). Components control or use the flow of electric current in order to carry out tasks.

Electronic signal A signal made by continuously changing the strength and direction of an electric current. Digital electronic signals use pulses of electricity to represent bytes (information stored in a digital form). Analogue electronic signals are patterns of gradually rising and falling current that can imitate, for example, a sound wave.

Email A system for sending messages almost instantly between any two internet users. Email is short for “electronic mail”.

Escape velocity The speed (about 40,000 km/h / 25,000 mph) a spacecraft must reach to overcome the pull of Earth’s gravity completely and travel beyond the Moon into outer space.

Exhaust Waste gases ejected from an engine.

F

Fighter jet A fast military aircraft, used in combat with other fighter jets or to intercept enemy bombers.

Flaps Hinged surfaces fitted to the edge of an aircraft’s wings. Flaps are used to extend the wing's area in order to provide extra lift during take-off and landing.

Foundations The lowest part of a building, which ensures its weight is supported on firm ground so the building cannot sink or fall.

Frequency The number of waves that pass a point each second. Different TV and radio stations are broadcast on carrier waves of different frequencies so they do not interfere with one another.

Fuselage The long body of an aircraft, containing the cabin.

G

Gears A set of cogs (interlocking toothed wheels). Gears are used to change the rate at which a mechanism rotates, called its torque or turning force. In a motor vehicle, gears link the engine to the wheels. In a low gear, the wheels turn much more slowly than the crankshaft. Low gears allow the engine to turn at high speed, even though the wheels are turning at low speed. This gives more torque.

Girder A large horizontal structure. It may support smaller beams, form the roof of a building or form the road deck of a bridge.

H

Hardware The physical parts of a computer, such as its electronic circuits and disc drives.

Helicopter A wingless aircraft that uses a main rotor for lift and a tail rotor to control its movement. A helicopter can hover forwards, backwards or sideways, and take off or land vertically.

Hot-air balloon A balloon filled with air heated by burners. It rises because the heated air is less dense than the surrounding air. Releasing hot air from the balloon makes it descend. Passengers travel in a gondola hung beneath the balloon. Hot-air balloons cannot be steered.

Hull The part of a ship that sits in the water. Inside the hull are decks and vertical walls called bulkheads.

Hybrid car A car powered by both an internal combustion engine and an electric motor.

Hydrofoil A speedboat with wing-like structures called foils. These raise the hull out of the water, reducing its drag (the force that would slow the boat down).

I

Integrated circuit An electronic circuit made of microscopic electronic components built into a small piece of silicon. Integrated circuits are often called silicon chips or microchips.

Internal combustion engine An engine that uses energy from burning fuel inside it to produce movement. Fuel and air are ignited inside cylinders, causing repeated explosions. These drive pistons inside the cylinders. In a car or motorbike, pistons turn the crankshaft, to which the wheels are connected. In a ship or some planes, the crankshaft turns the propeller. Rockets and jet engines are also internal combustion engines. In these, the fuel burns steadily, rather than exploding.

International Space Station (ISS) A space station orbiting about 350 kilometres (218 miles) above the Earth. It is made up of modules containing laboratories and living spaces.

Internet A network that links computers around the world. Most computers connect to an internet service provider via a telephone line or cable. Internet use includes email and the world wide web.

JK

Jet engine An engine in which compressed air is mixed with fuel and burned in a combustion chamber. The hot exhaust gas escapes at speed, providing forward thrust.

Jettison The deliberate release of something into space, the air or the sea.

Kerosene A highly flammable oil product that is used as fuel for jet engines.

L

Landing gear The wheels that support an aeroplane on the ground. After take-off, the landing gear often retracts into the nose of the fuselage and sideways into the undersides of each wing.

Laser A device that creates an intense beam of light, which hardly spreads as it travels. Lasers are used to cut metal, perform surgery and carry data along optical fibres.

Lift The upwards force, created by an aeroplane's wings, that keeps it in the air.

Lift-off The moment when a space rocket leaves the ground.

Light-emitting diode (LED) An electronic component that produces light when an electric current flows through it.

M

Maglev A type of train that moves by magnetic levitation. Powerful magnets fixed to the track push away from those fixed to the train in such a way that it moves forwards. The magnets also keep it floating just above the track. Because there is little friction, maglevs can reach very high speeds.

Microchip see Integrated circuit

Microphone A device that turns sound waves into electrical signals.

Microwaves High-frequency radio waves. Microwaves carry signals between transmitters and receivers, and to and from communications satellites.

Mobile phone A wireless telephone that connects to the telephone network by radio. The landscape is divided into cells, each with a fixed transmitter and receiver that mobile phones connect to.

Modulation The shaping of a radio wave to make it carry information. Modulation is done by using an electrical signal to change the strength of a wave—amplitude modulation or AM—or the frequency of a wave—frequency modulation or FM. Other types include pulse code modulation (PCM), used for sending digital signals.

NO

Network Two or more computers, phones or other devices that are connected so that they can exchange signals. Wireless networks connect these devices using radio waves instead of cables.

Offline Not being connected to the internet, or another computer network.

Online Being connected to the internet, or another computer network.

Optical fibre cable A cable that carries signals as pulses of light along a thin glass or clear plastic fibre.

P

Pantograph A device on a locomotive or tram that collects electricity from overhead cables in order to power its motor.

Petrol engine A type of internal combustion engine that uses electricity to create a spark and ignite petrol fuel.

Pile A buried pillar that provides the foundation for a building. It may be made of wood or metal driven into the ground by a machine called a pile driver, or from concrete poured into a deep hole.

Piston A part that moves up and down inside an engine’s cylinders.

Pixel A tiny coloured dot, which is the smallest part of a digital image. Pixel is short for “picture element”.

Program A set of instructions that controls what a computer does. Also called software.

Propeller A device formed of curved, rotating blades and connected to the engine of a plane, boat or ship. As the blades spin, air or water is sucked in around them and pushed backwards. This drives the plane or vessel forwards.

R

Radar A system that detects objects by transmitting radio waves and receiving the “echoes” that bounce back. Radar is used to detect other craft, storms and birds.

Radio waves Types of invisible energy waves. They can travel through air, space and some solids. Radio waves can be shaped, or modulated, in order to carry information for a wide range of uses, including the broadcasting of TV and radio programmes.

Rapid transit A passenger train, also known as an underground, metro or subway, that links up areas of a city. Trains often travel beneath the streets in the city centre but above ground in the suburbs. All underground trains are powered by electricity.

Receiver A device that detects signals, such as radio waves. For example, a radio receiver picks up radio waves and changes them back to the original electrical signal.

Resolution The concentration of pixels in a picture. High-resolution, or “hi-res”, graphics, made up of millions of pixels, can be viewed on a large screen without individual pixels becoming visible.

Robot A moving machine that carries out a series of actions, either on command or by being programmed beforehand and which can react to its surroundings. Robots are used in manufacturing industry, space exploration, underwater archaeology, healthcare, households, movies, security, bomb disposal and warfare. Advanced drones and driverless cars are also types of robot.

Rocket engine An engine that burns fuel, creating a stream of gases that drives the engine in the opposite direction. Spacecraft are normally carried into space by rockets, which function without air.

Rotor Long, rotating blades on the top of a helicopter that provide lift. Each blade has the curved aerofoil shape of an aeroplane’s wing. As the blades spin round, they push down the air beneath them, creating lift. Tilting the main rotor makes the helicopter move forwards, backwards or sideways.

Rover A vehicle used for exploration on the surface of a moon or planet. Rovers are robotic devices operated from Earth.

Rudder A flap mounted on the tailfin of an aircraft or underwater at a boat's or ship’s stern. When it turns, it changes the aircraft's or ship’s direction.

S

Satellite An artificial satellite is a device that has been launched into space and orbits the Earth. Communications satellites receive and transmit radio signals between ground stations on Earth. A natural satellite is a moon.

Satellite television TV broadcast via satellite. Signals are beamed to a satellite from a ground station. The satellite detects the signals and re-transmits them to receivers on Earth. They are received by aerial dishes pointed towards the satellite from people’s homes.

Search engine A software system designed to search for information on the world wide web. It works by using an automated "web crawler", or "spider". This continuously browses the web, storing information about the pages it comes across. Google and Bing are examples of search engines.

Semiconductor A material that can act as both a good conductor of electricity and as an insulator, a material that does not conduct electricity at all. The most common semiconductor material is silicon. The tiny electronic components and the connections between them on microchips are built into a wafer of silicon.

Ships Large vessels that carry passengers and cargo across the sea. Boats are smaller vessels designed for use on rivers and canals or in coastal waters. Many ships and boats are powered by a diesel engine, which drives a propeller.

Skyscraper A very tall building, usually more than 20 storeys high. Skyscrapers provide lots of space while using little land. They are often built in the centres of many large cities, where land is in short supply.

Smartphone A mobile telephone that also allows access to the internet, takes photographs and has many other functions.

Social media The software systems used by people to create, share or exchange information (for example, text, pictures or videos) with others via the internet.

Software A program, or set of programs, that a computer stores and uses. Application software makes a computer do specific jobs, such as play a computer game.

Solar panel A device that converts heat and light from the Sun into electricity.

Space probe An unmanned spacecraft, guided from Earth and used to take photographs and collect data from other planets and their moons. It is a type of robot.

Space Shuttle A reusable spacecraft that, from 1981 to 2011, flew into space like a rocket, then glided back to Earth like an aeroplane. Space Shuttles carried satellites into orbit. They also took people up to retrieve or repair them, or visit the International Space Station.

Spacecraft A machine designed to fly in space. Satellites, space stations, rocket launchers and space probes are all types of spacecraft.

Spaceflight A flight that goes further than 100 kilometres (60 miles) above the Earth’s surface. Aeroplanes cannot fly in space because their jet engines stop working through lack of oxygen. Spacecraft use rocket engines, which do not rely on oxygen in the air. Once in space, a spacecraft’s engines can be turned off. It largely keeps its speed because there is no air in space to slow it down (only the Earth's gravitational pull).

Spark plug An electrical device that ignites the fuel inside the cylinders of a petrol engine.

Submarine A boat that travels underwater. Submarines use ballast tanks to dive or surface. Large, ocean-going submarines are nuclear-powered, but smaller ones have electric motors, powered by batteries.

Submersible A miniature submarine, used for research in the ocean depths or to carry out underwater repairs.

Suspension bridge A bridge hung from steel cables strung between towers. Suspension bridges are ideal for long, high spans as they do not have a row of supporting columns that may interfere with river transport.

T

Tablet A flat, touchscreen computer that is convenient to carry around.

Tailfin The large vertical surface at the tail of an aircraft (or submarine). It keeps the plane (or sub) travelling in a straight line.

Tailplane A horizontal wing at the rear of an aircraft (or submarine). It prevents the plane (or sub) from pitching either up or down as it moves forwards

Tanker A large ship designed to transport liquids such as oil or chemicals.

Telecommunications The sending and receiving of information using electricity, radio waves or light. The information can be phone calls, radio programmes, TV pictures or computer data. Most forms of telecommunication require transmitters and receivers, and a network to link them together.

Thrust The force provided by an aeroplane's or rocket's engines. Thrust propels them forwards, overcoming the backward force of drag and the downward force of gravity.

Touchscreen An electronic visual display that the user can control by touching the screen with his or her finger. Touchscreens are used in game consoles, tablet computers and smartphones.

Transmitter An electronic device that gives out signals such as radio waves. An electrical signal, encoded on a carrier wave is fed to a transmitter, which turns it into a radio wave.

Tug A small, powerful boat used to push or pull large ships and steer them in and out of ports. Sometimes called a tugboat.

Turbine A machine that is turned by a liquid or a gas pushing against its movable blades. The turbine in a jet engine is turned by the jet exhaust. Its motion drives the compressor.

Turbofan A jet engine in which some cold incoming air bypasses the combustion chamber and turbine. This makes the engine cooler, quieter and more powerful than other engines. Turbofans are used in airliners and military aircraft.

Turboshaft A jet engine in which an extra turbine is used to turn a shaft. This then powers the rotors on a helicopter.

W

Website A collection of information, such as text and images, stored on the internet. People can access websites by means of the world wide web.

Wi-Fi A system that allows computers and “smart” devices like some mobile phones, printers and televisions to communicate over the internet using radio waves. Wi-Fi is short for Wireless Fidelity.

World wide web A huge information-sharing system. It allows computers, including tablets and smartphones, to ask for and copy files from another device. The files are stored in standard form so that any computer can read them. Often simply called the web.

Consultant: Mike Goldsmith