90 Engineering Trivia Questions and Answers
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Easy Engineering Trivia Questions
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An arch primarily carries loads through what kind of force?
Compression
The curved shape of an arch channels loads mainly as compressive forces through its voussoirs or blocks.
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Which ancient water-raising device needs no valves, lifts water one pocket at a time, and still drains fields and moves sewage today?
Archimedes' screw
Archimedes reportedly encountered the device in Egypt in the third century BC, though screw pumps may already have been irrigating fields there for centuries. The same design still works in reverse, spinning a turbine to generate hydroelectric power from a stream's fall.
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What type of energy does a battery store?
Chemical energy
A battery stores chemical energy. Reactions between its electrodes and the electrolyte release electrons, and only at that moment does the stored energy become electrical.
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What machine element supports a rotating shaft?
A bearing
A bearing supports a rotating shaft while reducing friction between moving parts. Many bearings use balls or rollers to help the shaft turn smoothly.
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Bridge deck joints are sized mainly to absorb movement caused by what?
Thermal expansion
Steel and concrete both expand in heat and contract in cold, so a long deck can shift by a noticeable amount between winter and summer. Without a joint to absorb that motion, the movement would crack the deck or crush the supports at each end.
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What circuit component stores electric charge in an electric field?
Capacitor
A capacitor stores separated electric charge and energy in an electric field.
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In chemistry, what is a substance that speeds up a reaction without being used up by it?
Catalyst
A catalyst offers the reaction an easier route by lowering the activation energy it has to climb, and comes out of the process unchanged. That is why a tiny amount can keep working on batch after batch.
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What chamber turns shaped clay into ceramic?
Kiln
A kiln fires shaped clay at high temperatures, transforming it into hard, durable ceramic. The heat removes moisture and triggers chemical changes that permanently strengthen the clay.
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What electrical safety device trips during an overload and can be reset afterward?
Circuit breaker
A circuit breaker senses too much current, snaps the circuit open, and can simply be switched back on once the fault is cleared. A fuse does the same job by destroying itself, so it has to be replaced every time.
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What does CNC mean in machine tools?
Computer numerical control
CNC machine tools use computer instructions to control tool movements and operations.
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What material combines reinforcing fibers with a surrounding matrix?
Composite
A composite combines strong reinforcing fibers with a surrounding matrix that binds them together and helps transfer loads. This combination can produce materials that are both lightweight and highly durable.
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What does CAD stand for, in engineering and design software?
Computer-aided design
Computer-aided design replaced the drawing board, letting a change to one dimension propagate through a whole model.
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What is a material that lets electric current flow through it easily called?
A conductor
Conductors such as copper, aluminium and silver hold their outer electrons loosely, so those electrons drift through the material and carry current with them. Insulators such as rubber and glass hold their electrons tightly, which is why cable is copper wrapped in plastic.
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What structure releases excess water from a dam?
Spillway
A spillway provides a controlled route for releasing flows from a dam to the downstream area, especially when water levels are high.
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What vehicle mechanism lets drive wheels turn at different speeds in a turn?
Differential
A differential allows driven wheels on the same axle to rotate at different speeds while receiving torque.
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What semiconductor component conducts current mainly in one direction?
Diode
A diode is a semiconductor component that allows current to flow mainly in one direction while resisting it in the other. Light-emitting diodes (LEDs) are a common type that produce light when current flows through them.
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Industrial distillation separates liquids mainly by differences in which physical property?
Boiling points
Distillation separates liquid components by exploiting differences in their boiling points.
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What rotating part stores energy to smooth a machine's motion?
Flywheel
A flywheel stores rotational energy and releases it to smooth fluctuations in a machine's motion.
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What process shapes heated metal with repeated blows or pressure?
Forging
Forging shapes heated metal through repeated hammering or pressing.
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An Icelandic power station drills wells to raise steam. What is that steam heated by?
Earth's internal heat
Geothermal systems use heat from inside Earth to produce steam or hot fluids for useful energy.
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Which historic fortification was built in stages over more than two millennia?
Great Wall of China
The Great Wall of China was built and rebuilt in stages over more than two thousand years, beginning with defensive walls constructed as early as the 7th century BCE. Its surviving sections stretch for thousands of kilometers across northern China.
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In a conventional hydroelectric plant, what does the turbine spin?
Generator
The turbine drives a generator, which converts the water's mechanical energy into electricity.
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Which invention drove much of the Industrial Revolution's mechanization?
Steam engine
Water wheels and windmills tied a mill to a particular river or to the weather. A coal-fired steam engine could be built anywhere and run all year, which is what let factories, mines and railways scale up.
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What type of jet engine powers most modern airliners?
Turbofan
A turbofan sends most of its air around the hot core rather than through it, which makes it far quieter and much more fuel-efficient than the turbojets that powered the first airliners.
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What is the fixed pivot point of a lever called?
Fulcrum
A lever rotates about a fixed point called its fulcrum.
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Which ions shuttle between the electrodes of the rechargeable batteries in phones and laptops?
Lithium ions
Charging drives lithium ions out of the cathode and into the graphite anode, where they sit between layers of carbon; discharging lets them travel back, and the electrons taking the long way round the external circuit are what power the device. Because that movement is reversible, the same cell can be run down and refilled hundreds of times.
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What substance is applied between moving machine parts to reduce friction?
Lubricant
A lubricant holds a thin film between two surfaces so they slide across the film instead of grinding against each other. That cuts wear, saves the energy friction would otherwise waste, and keeps down the heat that grinding produces.
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What reaction releases energy in today's conventional power reactors?
Nuclear fission
Today's conventional power reactors release energy through nuclear fission rather than fusion, oxidation, or radioactive decay.
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What law relates voltage, current, and resistance?
Ohm's law
Ohm's law states that voltage equals current multiplied by resistance for an ohmic conductor.
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What minimum speed lets an object leave a body's gravity without further propulsion?
Escape velocity
Escape velocity is the speed required to break free from a celestial body's gravitational field.
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What structures raise and lower ships through the Panama Canal?
Locks
Canal locks raise ships to Gatun Lake and lower them again to sea level.
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What engine component reciprocates inside a cylinder?
Piston
A piston is the engine component designed to travel back and forth within a cylinder. The alternatives are genuine engine components but operate elsewhere or serve different functions.
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What does water in a plumbing trap block?
Sewer gases
The standing water in a plumbing trap forms a seal that prevents sewer gases from flowing back into a building. If the water evaporates, those gases and odors can enter through the drain.
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What simple machine uses a grooved wheel and rope?
Pulley
A pulley is a grooved wheel around which a rope or cable runs.
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An air-traffic control tower finds an aircraft's range and bearing by bouncing what off it?
Radio waves
Radar uses radio waves, which bounce off objects and return to the radar receiver to reveal their location. The word “radar” comes from “radio detection and ranging.”
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What is commonly embedded in concrete to help it resist tension?
Steel reinforcing bars
Concrete performs well in compression but poorly in tension, so steel reinforcement is embedded to carry tensile forces.
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What does RPM measure?
Revolutions per minute
Revolutions per minute counts full turns of a shaft each minute, which is why a car's tachometer and a record player both use it.
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Rocket thrust is usually explained by which of Newton's laws?
Newton's third law
A rocket engine hurls exhaust gas backwards at high speed and gets an equal and opposite push forwards. That is Newton's third law, and it is why a rocket works in the vacuum of space, where there is nothing outside to push against.
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Which Roman waterworks brought fresh water from distant sources to cities?
Aqueducts
Roman aqueducts transported fresh water from distant springs and rivers into cities. The Pont du Gard in France is a remarkably preserved example, carrying water across the Gardon River on three tiers of arches.
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A screw is a simple machine based on what?
Inclined plane
A screw is an inclined plane wrapped around a cylinder.
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Which element is the dominant semiconductor material in conventional solar cells?
Silicon
Silicon is the dominant semiconductor material used in conventional solar photovoltaic cells.
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Which element helps stainless steel resist corrosion?
Chromium
Chromium in stainless steel forms a thin, adherent oxide layer that helps protect the alloy from further corrosion.
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The Three Gorges Dam was built across which river?
The Yangtze
The Three Gorges Dam is a concrete gravity dam at Sandouping in Hubei province, holding back the Yangtze behind a wall over two kilometres wide. It is the largest power station in the world by generating capacity, and filling its reservoir displaced more than a million people.
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What device raises or lowers voltage in power lines?
Transformer
Transformers can increase or reduce voltage as electricity travels from power plants to homes.
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What semiconductor device provides signal gain and serves as an electronic switch?
Transistor
A transistor is a semiconductor device that can amplify electrical signals and act as an electronic switch. The first working transistor was built at Bell Labs in 1947.
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What geometric shape is repeated in a typical truss to distribute loads?
Triangles
A triangle is the only polygon that cannot change shape without changing the length of a side, so a triangular frame stays rigid under load, while a four-sided frame can rack sideways into a parallelogram unless it's braced. Named patterns like the Warren and Pratt truss are just different arrangements of that same triangle.
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What component controls the flow of a liquid or gas in a pipe?
A valve
Valves regulate the movement of liquids or gases through piping systems.
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Which simple machine is used to split or separate material?
A wedge
A wedge is a simple machine used to split, separate, or cut material. It works like two inclined planes joined together, directing force outward to push materials apart.
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What process joins metal parts by fusing their surfaces?
Welding
Welding joins metal parts by fusing their surfaces, using heat, pressure, or both. In gas metal arc welding, a continuously fed wire electrode melts to form the joint while shielding gas protects the molten metal from contamination.
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A doorknob is an example of which simple machine?
A wheel and axle
Turning the wide knob turns the narrow spindle inside it, and the difference in radius multiplies the force you apply. A steering wheel, a screwdriver handle and a tap all work the same way.
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Which aircraft made the first powered, controlled flight, at Kitty Hawk in 1903?
Wright Flyer
The Wright Flyer made four flights on 17 December 1903. Orville took the first, covering 120 feet in 12 seconds, and Wilbur flew the longest of the day at 852 feet in 59 seconds. A gust flipped the machine on the ground later that afternoon and it never flew again.
Medium Engineering Trivia Questions
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Which principle explains how a hollow steel ship can float?
Archimedes' principle
Archimedes' principle says a floating object is held up by a buoyant force equal to the weight of the water it pushes aside, and a hollow hull displaces far more water than its own weight.
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What beam is fixed at one end and free at the other?
Cantilever
Bending stress in a cantilever peaks at the fixed support and drops to zero at the free tip, which is why a diving board flexes most near the anchor point. Scotland's Forth Bridge, opened in 1890, is a famous example built at railway scale.
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What failure occurs when a slender column suddenly bends sideways?
Buckling
Buckling is the sudden sideways bending of a slender column under compression. The critical load depends strongly on the column’s length, with longer columns buckling under much smaller loads.
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In a disc brake, which part clamps the friction pads onto the rotor?
The caliper
The caliper straddles the spinning disc and uses hydraulic pistons to squeeze the friction pads against it, turning the car's momentum into heat. Everything upstream of it only supplies the pressure.
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What material forms the Eiffel Tower's lattice?
Wrought iron
The tower is built from puddled iron, a very pure form of wrought iron. Its roughly 18,000 pieces were cut and drilled in Eiffel's workshops at Levallois-Perret, then riveted together on site with more than two million rivets.
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Which manufacturing process forms a continuous profile by forcing material through a shaped die?
Extrusion
Extrusion pushes heated or softened material through a die cut to the shape you want, producing a continuous length with that cross-section, which is then cut to size. Aluminum window frames, plastic pipe and most pasta shapes are made this way.
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What kind of failure builds up from repeated cycles of stress, even when every single cycle stays well below the breaking load?
Fatigue
Fatigue is a crack that grows a fraction with each cycle of stress until the part snaps at a load it had survived thousands of times before. This is what metal fatigue means in aircraft, and why airframes are retired after a set number of flights rather than when they look worn.
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What does a hydrogen fuel cell do with the hydrogen in order to produce electricity?
Combines it with oxygen across a membrane without ever burning it
Hydrogen is stripped of its electrons at the anode. The membrane in the middle lets only protons through, so the electrons have to travel the long way round through an external circuit, and that flow is the current. On the far side they meet the protons and oxygen from the air and form water. Nothing is set alight, which is why the exhaust is water vapour and warmth.
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Which engineer is known as the 'Father of Railways' for building the locomotives of the world's first public steam railway, opened in 1825?
George Stephenson
Stephenson engineered the Stockton and Darlington Railway, which opened on 27 September 1825 as the first public railway worked by steam locomotives, with his Locomotion No. 1 hauling the opening train.
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What process strengthens glass by heating it and then rapidly cooling it?
Tempering
Tempering heats glass close to its softening temperature and then rapidly cools it, creating stresses that increase its strength.
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A GFCI outlet is fitted near sinks and bathtubs because it cuts the power when it detects what?
Current leaking to earth
A GFCI constantly compares the current going out along the live wire with the current coming back on the neutral. If even a few thousandths of an amp go missing, because they are travelling to earth through a person, it cuts the circuit in a fraction of a second.
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In engineering, what device moves energy between two fluids without joining their streams?
Heat exchanger
A heat exchanger transfers thermal energy between two fluids while keeping their streams separate. Many use tubes and surrounding shell surfaces to allow heat transfer without mixing the fluids.
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In building services, what does HVAC stand for?
Heating, ventilation and air conditioning
The three functions are treated as one system because they share the same ducts, controls and energy budget.
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Which plastics process melts pellets in a heated screw barrel and forces the melt into a cooled mold?
Injection molding
In injection molding one rotating screw both melts the plastic and rams it into the mould, so a part can be filled, cooled and ejected in seconds. That short cycle is what makes it the standard way to turn out identical plastic parts by the million.
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What is the contaminated liquid that drains out of a landfill called?
Leachate
Rain soaking down through buried waste dissolves whatever it passes and collects at the bottom of the tip as leachate. Modern landfills are built on sealed liners with collection pipes that draw it off for treatment before it can reach groundwater.
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In tyre and boiler pressure, what does PSI stand for?
Pounds per square inch
Pounds per square inch is a force spread over an area, which is what pressure is. The metric equivalent is the pascal.
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What pressure-vessel device opens to prevent dangerous overpressure?
Relief valve
A relief valve opens at a set pressure to discharge fluid and protect equipment from overpressure.
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What does reverse osmosis force water through to remove dissolved salts?
Semipermeable membrane
Reverse osmosis uses pressure to force water through a semipermeable membrane that blocks dissolved salts and many other contaminants. The purified water passes through while the concentrated salts remain behind.
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Some buildings in earthquake zones sit on flexible rubber-and-steel bearings instead of directly on their foundations. What is this technique called?
Base isolation
Base-isolated buildings rest on layered rubber-and-steel or sliding bearings that flex sideways. In a quake the ground and foundation shift back and forth underneath while the structure above moves far less, and much less energy reaches the walls and floors.
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What effect converts light directly into electrical current in a solar cell?
Photovoltaic effect
The photovoltaic effect creates an electric voltage and current when light interacts with a semiconductor junction.
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In a suspension bridge, what connects the main cables to the roadway?
Suspender cables
Vertical suspender cables, also called hangers, drop from the main cables and carry the deck's weight up into them.
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In a running diesel engine, what ignites the fuel?
The heat of the air compressed in the cylinder
A diesel squeezes air hard enough to make it hot enough to ignite the fuel sprayed into it. Glow plugs only warm the cylinder for cold starting and switch off once the engine runs.
Hard Engineering Trivia Questions
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Which type of dam is thin, and pushes most of the water's load sideways into the rock walls of a narrow gorge?
Arch dam
An arch dam curves into the flow so the load is carried in compression around the arch and into the rock abutments, which is why it needs a narrow gorge with strong walls.
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Which bridge type uses cables running directly from towers to the deck?
Cable-stayed bridge
In a cable-stayed bridge, inclined cables run straight from the towers to the deck. A suspension bridge instead hangs the deck from a draped main cable.
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Which chemical family is used in many carbon-dioxide capture solvents?
Amines
Aqueous amine solvents can selectively absorb carbon dioxide and release it during regeneration.
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What is the name for a robot arm that moves along three perpendicular linear axes?
Cartesian robot
A Cartesian or gantry robot travels on three straight axes at right angles, matching x, y and z coordinates. Most desktop 3D printers use the same arrangement.
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Who built the first working pendulum clock, cutting timekeeping error from about fifteen minutes a day to well under a minute?
Christiaan Huygens
Huygens had a working pendulum clock by the end of 1656 and patented it in 1657. Galileo had proposed the idea years earlier but never got one running.
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Which aircraft navigation system calculates position from gyroscopes and accelerometers?
Inertial navigation system
An inertial navigation system tracks every turn and acceleration from a known starting point, so it needs no outside signal at all.
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In lean manufacturing, what does the Japanese term muda refer to?
Work that adds no customer value
Toyota engineer Taiichi Ohno grouped it with two related ideas: mura, unevenness in the flow of work, and muri, overburdening people or machines. Together the three are systematically hunted down on the shop floor, the core of the production system he built after the Second World War.
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Stereolithography, the first commercial 3D-printing process, builds each layer by hardening what?
Liquid resin
Chuck Hull's stereolithography traces an ultraviolet laser across a vat of liquid photopolymer resin, curing it a layer at a time. The first machine, the SLA-1, went on sale in 1987.
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The first lasting transatlantic telegraph cable, completed in 1866, ran from Valentia Island in Ireland to Heart's Content on which island?
Newfoundland
The steamship Great Eastern paid out the cable from Valentia and landed it at Heart's Content in eastern Newfoundland on 27 July 1866, creating the first permanent telegraph link between Europe and North America.
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What material forms the core of most long-distance optical fibers?
Silica glass
Extremely pure silica glass forms the core and cladding of long-haul fibre. Plastic fibre exists but loses too much light beyond short runs.
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Six Sigma sets a quality target of how many defects per million opportunities?
3.4
The name refers to fitting six standard deviations between a process average and the nearest limit a customer will accept. Allowing for the drift a real process shows over months of running, that works out at 3.4 defects for every million chances to make one, the figure Six Sigma programmes quote as their target.
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How does an ablative heat shield protect a spacecraft during reentry?
It burns away, carrying the heat off with the lost material
The outer layer of the shield chars, melts and vaporises as the capsule ploughs into the atmosphere. The material boiling off carries the reentry heat away into the surrounding gas instead of letting it conduct inward, so the shield is deliberately used up while the capsule stays cool behind it.
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At what stress does plastic deformation begin in a material?
Yield strength
Yield strength is the stress at which a material begins to deform plastically rather than elastically.
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What land-surveying instrument measures horizontal and vertical angles?
Theodolite
A theodolite is a precision surveying instrument used to measure horizontal and vertical angles. Modern electronic theodolites display these measurements digitally and are often combined with distance-measuring technology in total stations.
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Which ancient Roman concrete ingredient helped some marine structures harden underwater?
Volcanic ash
Volcanic ash, or pozzolana, reacted with lime and seawater to grow durable mineral crystals, which is why Roman harbour concrete set under water and still stands.
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Which drinking-water treatment step uses gentle mixing to aid particle removal?
Flocculation
Flocculation uses gentle mixing to help small particles clump together into larger, heavier flocs that are easier to remove. It typically follows coagulation and prepares the particles for sedimentation or filtration.
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The rust-brown surface of Antony Gormley's Angel of the North comes from which type of steel?
Weathering steel
The Angel is built from COR-TEN weathering steel. Its copper-bearing alloy grows a tight rust-coloured patina that seals the surface instead of needing paint.
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