Applied Science

Mains Voltage

This is a classic trap for the unwary question setter.

Mains voltage in the UK was traditionally 240 volts +/- 6%.

On continental Europe, the standard was 220 volts.

In 1994, in order to remove a perceived barrier to trade between European countries, the EC decided to 'harmonise' the standard European mains voltage at 230V. But this was a purely bureaucratic measure; there was no technical advantage in increasing the continental voltage or decreasing the UK voltage, and the cost of replacing the electricity supply equipment across Europe was prohibitive. So in fact, all that changed was the tolerances.

The UK regulations were changed (effective from 1 January 1995) to require 230 volts, with a higher tolerance of 10% and a lower tolerance of 6%. This allows anything between 216.2 and 253.0 volts. (Note that previously anything up to 254.4 volts was legal, so the increased upper tolerance of 10% almost makes up for the reduced standard voltage.)

To quote an answer on Yahoo (dated 2007): " ... [the UK electricity supply industry] keep[s] on generating as close as [it] can to 240V, the Continentals generate as close as they can to 220V, we all pretend it's 230V and everybody is happy!"

And another (also dated 2007): "It's a fudge and we all know it but it's probably one of the more sensible and pragmatic bits of standardisation that we've seen in the E.U."

It does, however, leave something of a dilemma for the quizzer who is asked "What is the standard mains voltage in the UK?" Arguably, the legal standard is 230 volts (with tolerances as stated in the previous paragraph); but the practical standard remains at 240 volts.

If you try and explain the above to the person who's asking the questions, I suspect that you may get short shrift. My advice, for what it's worth, is to answer "240 volts"; this was the expected answer the last time I was asked this question (in November 2014). If the question person responds with "Actually the regulations changed in 1995 ... " you have all the information you need in order to argue your case.

Good luck!

P.S. I am indebted for the above detailed information to TwoThirtyVolts.org.uk.

P.P.S. TwoThirtyVolts states that "In 2010, the voltage tolerance band may be increased to ± 10% but again, in reality, nothing will really change!" I can't find out whether this ever did happen (which suggests that it didn't) – but like they said: even if it did, the answer to the quiz question is still the same.

P.P.P.S. What will happen, or has already happened, now that the UK has left the EU, I do not know. I'm guessing that 230 volts will continue to be the legal requirement (and 240 volts the practical standard) until the Government gets round to changing it.

Other countries

Outside Europe, not surprisingly, each country has its own standards. The main thing to be aware of is that in the USA and Canada, and in many countries within their sphere of influence (several Caribbean and Central American countries, for example) it's 120 volts.

Japan has the lowest figure of all (unless there's one I've missed), at 100 volts.

In many countries with British heritage but not under the EU influence (e.g. Kenya, Kuwait, Nigeria and Uganda) it's still 240 volts.

Otherwise, 220 or 230 volts is pretty much a worldwide standard.

Plugs (wiring of – UK)

	Old	New
Live	Red	Brown
Neutral	Black	Blue
Earth	Green	Green & yellow

Fire extinguishers: UK standards

This is a complicated subject, not least because the standards and the technology keep changing.

Since 1997, UK fire extinguishers have conformed to European standards which require the extinguisher to be red, with a coloured band (covering between 5% and 10% of the surface area) indicating its type.

The most complicated aspect is the different types of fire for which each type of extinguisher is recommended. Quiz setters therefore tend to avoid it, and stick to asking which type of extinguisher is indicated by a particular colour. You are unlikely to get asked, for example, "What type of fire extinguisher is recommended for use on electrical fires?" (Answer: "Powder, carbon dioxide or water mist" – see below.)

For completeness, the different types of fire are:

A:	freely burning materials – typically organic substances such as wood, paper, straw, textiles, coal
B:	flammable liquids, including petrol, diesel, oils, paint and paraffin
C:	flammable gases, including methane, propane and natural gas
D:	flammable metals, including magnesium, aluminium and Lithium
E:	electrical equipment, including computers, video and audio equipment, and fuse boxes
F:	combustible cooking materials – typically cooking oil

Colour	Type	Recommended for (types)
Blue	Powder	B, C, E, and sometimes A
Cream	Foam	A, B
Black	Carbon dioxide	B, E
Red	Water	A
Yellow	Wet chemical	A, F, and sometimes B
White	Water mist	A, F, E

Catalytic Converters

The three main processes carried out by a modern catalytic converter are:

	Oxidation of carbon monoxide to carbon dioxide
	Oxidation of unburnt hydrocarbons to carbon dioxide and water
	Reduction of nitrogen oxides to nitrogen and oxygen

Early ('two–way') catalytic converters only carried out the first two of these processes.

The three precious metals that are most often used in a modern catalytic converter are:

The first of these three is the most widely used of all.

Inventors

Processes

Produced by the Wohler process		Acetylene
Extracted from its chief ore using the Bayer process (which extracts the oxide) and the Hall–Héroult process (which electrolyses the metal from the oxide)		Aluminium
Produced by the Haber process (a.k.a. Haber–Bosch or Fritz–Haber)		Ammonia
Produced by the Solvay process		Sodium carbonate
Produced by the Bessemer process		Steel
Extracted from underground deposits by the Frasch process or Sicilian process		Sulphur
Produced by the Contact process (Joseph Louis Gay–Lussac patented an earlier process)		Sulphuric acid
Extracted from its principal mineral ores by the Kroll process (and before that, the Hunter process)		Titanium

The best–known of all these processes (and the most important ones for quizzers to remember) are probably the Haber and the Bessemer – followed by the Bayer and the Contact.

Other

Nominal output voltage of a primary (non–rechargeable) single–cell alkaline battery – e.g. A, AA, AAA or N – or a classic Leclanché cell (wet cell)			1.5 volts
Temperature for pasteurisation			63°C
Standard mains voltage in the UK (traditionally – see next question)			240
In 1994, the EC decided to 'harmonise' the standard European mains voltage at			230V
Revolutions per minute (rpm) of a compact disc			250
Produced by combining water and calcium carbide (gas with the formula C₂H₂ – process discovered by Friedrich Wohler in 1862)			Acetylene
Common UK name for a hexagonal key, used to drive screws and bolts – a.k.a. hex key or (trade name) Unbrako key			Allen key
Haber (Haber–Bosch, Fritz–Haber) process combines nitrogen and hydrogen to produce			Ammonia
High–grade coal, over 90% carbon, mined in Pennsylvania and South Wales			Anthracite
Most common use for ethylene glycol (propylene glycol, which is considerably less toxic, is used for the same purpose in food–processing systems, water pipes in homes, etc.)			Antifreeze
Gaseous element used to fill light bulbs (because of its lack of reactivity; if air were used, the bulb filament would react with the oxygen and burn away)			Argon
Coil of an electric motor			Armature
A mixture of bitumen and mineral aggregate, used to pave roads – often colloquially referred to as tarmac			Asphalt
Machine that uses high–pressure saturated steam to sterilise equipment and supplies			Autoclave
The first plastic made from synthetic components (1907); named after its inventor, who was trying to find a substitute for shellac; used in electrical insulators, radio and telephone casings			Bakelite
The voltaic pile (1799) was the first			Battery
Produced (sometimes) by the Burton Union method			Beer
Device used in thermostats, consisting of two different metals (typically steel and copper) welded together, whose different expansions force it to bend if heated			Bimetallic strip
Porroprism or roof prism: part of			Binoculars
Organic matter derived from living, or recently living organisms, used as a source of energy; also a term used in ecology to refer collectively to all living biological organisms in a given area or ecosystem at a given time			Biomass
Highly viscous mixture of organic liquids, used in paving roads (usually mixed with mineral aggregate to form asphalt)			Bitumen
The vessel in which smelting (particularly of iron) takes place			Blast furnace
Reproduction technique invented in 1861 by French chemist Alphonse Louis Poitevin, traditionally used for architectural and engineering designs – used colloquially for any detailed plan			Blueprint
Britain's first nuclear power station, and the first in the world to generate electricity in commercial quantity: located on the Sellafield site in Cumbria, and operating from 1956 to 2003, it produced the plutonium that was used in Britain's nuclear weapons			Calder Hall
Converts rotary motion into linear			Cam (shaft)
Latin phrase for "veiled room" – used for a room where an image of the outside wall is projected through a pinhole onto the wall (using the principle of the pinhole camera, of which this is a precursor)			Camera obscura
A structure that projects horizontally into space, supported at one end only			Cantilever
Once known as a condenser: the more modern name for a device that can store electric charge is			Capacitor
Gas that makes bread rise (produced by fermenting yeast)			Carbon dioxide
Jet, needle valve and float: found in a			Carburettor
Comparatively brittle form of iron, with 2–4% carbon and 1–3% silicon			Cast iron
Lost wax (French: cire perdue) is the standard method of			Casting metal
Thin, springy wire that made adjustable contact with a crystal of semiconducting mineral, in early crystal radio sets (c. 1906–45)			Cat's whisker
Polymer that is the main constituent of plant cell walls; used to make paper			Cellulose
Made by grinding clinker with a small amount of gypsum			Cement
Blackish residue of impure carbon, obtained by removing water and other volatile constituents from organic matter (typically by heating wood in the absence of oxygen)			Charcoal
The hard substance formed when limestone (calcium carbonate) is heated to form quicklime (calcium oxide), which then blends with small amounts of other materials (such as clay); ground with gypsum to form cement			Clinker
Solid, carbon–rich leftover of the destructive distillation of bituminous coal (after the coal has been baked at extremely high temperatures in an airless oven to drive off the volatile constituents such as water, coal–gas and coal–tar)			Coke
Device for reversing the direction of a current; in a DC motor or generator, an assembly for changing the frequency or direction of the current in the armature windings			Commutator
Made by mixing cement with water (and other additives)			Concrete
Made in a ginnery			Cotton
Breaking down crude oil into simpler molecules			Cracking
Principal use of Prague powder (No. 1 and No. 2)			Curing food
Computer system introduced in 1980 to adjudicate on close line calls at Wimbledon (and later at the US and Australian Opens) – replaced at Wimbledon in 2007 by Hawk–Eye			Cyclops
Variable–ratio transmission system commonly used on bicycles: consists of a number of differently–sized sprockets and a mechanism to move the chain from one to another. Commonly referred to as gears, although strictly speaking they aren't			Derailleur
Removal of salt and other dissolved minerals from sea water			Desalination
Name given to any specialised tool used in manufacturing industries to cut or shape material, typically using a press – generally customised to the item it's used to create			Die
Foreshots, heads, hearts, tails and feints are vapours associated with (process)			Distillation
Perchloroethylene: used in			Dry cleaning

The armature, brushes and commutator are parts of a(n)

Installed by Jesse W. Reno at Coney Island amusement park, 1896: the first working		Escalator
The most commonly produced organic compound in the world; its polymer form (polyethylene or polythene) is used to make plastic carrier bags; also causes fruit to ripen and is given off by bananas		Ethylene (ethene)
British scientist: gave his name to the cage that protects electrical equipment from lightning		Faraday
Nuclear reactor that produces more fissile material than it consumes		Fast breeder
Sodium thiosulphate (incorrectly known as hypo): used by photographers for		Fixing
The A200, patented by Kenneth Wood in 1947 and first marketed in 1950, was a		Food mixer
Name, originating in its use in the textile industry to clean raw wool, given to any natural material used to to remove impurities or colouring from fats, grease, or oils; consists chiefly of hydrated aluminum silicates that contain metal ions such as magnesium, sodium, and calcium; used in hygiene, decontamination, and in the film industry to make explosions look more spectacular; also used in cat litter!		Fuller's earth
Sodium carbonate (soda) and calcium oxide (lime) are the two main ingredients of		Glass
Crystalline form of carbon, sometimes known as plumbago or black lead, from which pencil leads are made		Graphite
Mixture of water, sand and cement, used to fill voids; also a urethane or epoxy used to seal the joints between tiles		Grout
Saltpetre (potassium nitrate), charcoal, sulphur (typically 75%, 13% and 12% respectively)		Gunpowder
Computer system developed 2001 by Roke Manor Research of Romsey, Hampshire, to visually track the paths of cricket balls; used from 2001 in TV cricket coverage, from 2006 in tennis (Wimbledon since 2007, where it replaced Cyclops), officially in cricket from 2009, and in the Premier League since 2013; also used by the BBC in its snooker coverage, but not by the official snooker authorities		Hawk–Eye
Used to inflate airships etc., in preference to hydrogen as not inflammable		Helium
In order to reduce the narcotic effects, deep–sea divers breathe a special mixture of gases, which has less nitrogen and oxygen than air and increased levels of		Helium
Massive scalar elementary particle, the last of the predicted Standard Model particles to be observed – observed at the European LHC in 2012, after a 40–year search		Higgs boson
A refractory material is one that's suitable for use in		High temperatures
A 3–dimensional image created by a laser		Hologram
The Saunders–Roe, Nautical 1 (SR.N1) – launched in June 1959, famously crossing the English Channel 44 days later – was a prototype of the		Hovercraft
The Vickers–Armstrong VA–3, which carried passengers between Rhyl (Denbighshire) and Moreton (on the end of the Wirral peninsula) from 20 July to 14 September 1962, was the first ... to enter service		Hovercraft
The world's largest experimental nuclear fusion reactor – operational at Culham, Oxfordshire, since 1982		Joint European Torus (JET)
Familiar name for a worm drive hose clip (patented 1921 by L. Robinson & Co. of Gillingham, Kent)		Jubilee clip
Developed in Germany in 1901 and introduced in Britain in 1903, the Prometheus was the first electric		Kettle
Synthetic fibre, noted for its high tensile strength and used in bicycle tyres, boat sails, and body armour: developed by Stephanie Kwolek at DuPont in 1965		Kevlar
17–mile underground proton accelerator at CERN, Geneva – began operating 2008; it was confirmed in 2013 that it had discovered the Higgs boson (the so–called 'God particle'		Large Hadron Collider
Sodium thiopental, Pancuronium bromide, and potassium chloride (in that order)		Lethal injection
First installed in a New York store (Eder V. Haughwout's fashionable chinaware emporium) in 1857		Lift (elevator)
Method of road construction (and its product) involving three layers of aggregate of decreasing size – named after its Scottish inventor. See Tarmac		Macadam(isation)
Simple generator used to produce short pulses of current – used for ignition in motorcycles and early cars		Magneto
Alnico (the generic name for a family of alloys of iron, aluminium, nickel and copper) is used for making		Magnets
Name given to a shaft or bar, the end of which is inserted into a workpiece to hold it during machining, a spindle on which a circular saw or grinding wheel rotates, or the driving spindle in the headstock of a lathe		Mandrel
Fluorescent tubes contain an inert gas (e.g. neon or argon) and		Mercury vapour
Natural gas (widely used as a fuel since the development of long distance pipelines in the early twentieth century) consists primarily of		Methane
A (cavity) magnetron is a vacuum tube that generates		Microwaves
Used in building, particularly bricklaying: made by mixing cement and sand with water		Mortar
The main active ingredient of mothballs (formula C₁₀H₈)		Naphthalene
Used in "smoothflow" beers (instead of the more "traditional" carbon dioxide) – released into a can of beer by a 'widget' when the can is opened		Nitrogen
The first practical explosive produced that was stronger than black powder: first synthesized by the Italian chemist Ascanio Sobrero in 1847; used in the manufacture of dynamite (which is a safer alternative)		Nitroglycerin(e)
Most important group of synthetic polyamides		Nylons
The mirror or lens that gathers the light, in a telescope (in the case of a lens, it's the one nearest to the source)		Objective
Represents an electric signal as a spot of light moving across the screen of a cathode ray tube		Oscilloscope
Kerosene – used as aviation fuel, rocket fuel and lighter fuel, also used in cooking – is more commonly known in the UK as		Paraffin
The process of heating food (especially milk) to kill harmful organisms		Pasteurisation
Raw iron – the immediate product of smelting iron ore with coke and limestone in a blast furnace		Pig iron
Laboratory instrument used to transport a measured volume of fluid		Pipette
Name used for any of a number of highly viscous liquids which appear to be solid (often used interchangeably with tar, although strictly speaking tar is more liquid)		Pitch
Name used for the distance between each complete turn of the thread, on a screw		Pitch, or lead
Principally used as propellants in aerosols, now that CFCs are considered environmentally unsafe		Propane, butane
The Archimedes screw is a device for		Raising water
Converts AC current to DC		Rectifier
Two types of telescope used in optical astronomy		Refractor, reflector
Represented in an electrical circuit diagram by a zigzag line		Resistor
Variable electrical resistance		Rheostat
Neoprene is a synthetic form of		Rubber
Commonly used in dishwashers to soften the water		Salt
English engineer Joseph Whitworth, in 1841, devised and specified the first international standard for; British Standard Fine (BSF) is an alternative		Screw threads
General–purpose plastic explosive, manufactured under its present name in Czechoslovakia / Czech Republic since 1964; previously made for military purposes as B1. Popular with terrorists because it was, for many years, extremely difficult to detect		Semtex
Thickness of metal between foil and plate		Sheet
Layered combination of silver and copper, invented 1743 by Thomas Boulsover; used for many years to produce a wide range of household articles, but superseded around 1820 by the use of nickel silver instead of copper, and from about 1840 by the invention of electroplating		Sheffield plate
The process of applying heat to an ore, in order to extract the base metal that it contains		Smelting
The sodium salt of a long chain carboxylic acid (fatty acid) – e.g. the stearate, oleate or palmitate; alternatively, sodium or potassium salts of fatty acids – derived from glycerides (vegetable oils or animal fats)		Soap
The DIN number on a photographic film denotes the		Speed of the film
Invented around 1913 by the Sheffield laboratory researcher Harry Brearley		Stainless steel
Particularly hard and strong alloy of iron with approx. 1% of (traditionally) carbon, originally produced in Sheffield 1855 by Henry Bessemer (by the process, and in the converter, that bear his name). The process actually removes most of the carbon from pig iron		Steel
Can be mixed with sodium chlorate to form an explosive		Sugar
Vulcanisation: rubber is heated with		Sulphur
Acid used in car batteries (usually)		Sulphuric
Space at the bottom of a system for collecting liquid (e.g. in an engine – where it may be known as the oil pan – or a building)		Sump
Molten animal fat used in candles and soap		Tallow
Viscous black liquid resulting from the destructive distillation of organic matter – produced most commonly from coal as a result of coke production, but also from petroleum, peat or wood		Tar
Type of road surface patented 1901 by E. Purnell Hooley – bought 1905 by Sir Alfred Hickman MP, who turned it into a highly successful company of the same name. It is essentially a method of macadamisation, using tar to stabilise the surface and reduce the amount of dust, and then compacting with a steam roller. See asphalt		Tarmac
Accidentally discovered by US chemist Roy Plunkett and his assistant Jack Rebok, at the DuPont company laboratory in Deepwater, New Jersey, while carrying out research into refrigerants		Teflon (PTFE)
Metallic element used in hip replacements as not affected by body fluids		Titanium
Machine conceived by Soviet physicist Andrei Sakharov for investigating nuclear fusion (acronym for toroidal magnetic chamber)		Tokamak
Principle first patented in Germany 1928; developed (and named) at Bell Laboratories, 1947–51		Transistor
Changes the voltage of AC without changing the frequency		Transformer
Metallic element most commonly used for the filament in electric light bulbs		Tungsten
A machine that uses the energy in a moving fluid to produce rotary motion (by action on the vanes, or blades, attached to a shaft, drum or cylinder)		Turbine
The process of turning rubber into more durable materials by introducing sulphur or other "curatives"		Vulcanisation
Semicircular key, named after its 19th century US inventor – a.k.a. half moon key		Woodruff key
Pure iron with very low carbon content – tough, malleable and ductile, but too soft to be used for cutting edges		Wrought iron
Gas used in lasers, incandescent lamps, electronic flash lamps		Xenon
Galvanisation involves coating with		Zinc

English inventor, best remembered for the first commercially successful process (which became known by his name) for mass–production of steel, by melting pig iron and blowing air through it to remove the impurities (in 1856)		Henry Bessemer
Sheffield industrialist who invented stainless steel (around 1913)		Harry Brearley
Invented a system for noise reduction in analogue magnetic recordings – 1966 (the best known version was invented in 1968)		Ray Dolby
French inventor of a lens of large aperture and short focal length, using minimal volume and weight of material – used in lighthouses		Augustin–Jean Fresnel (fray–NELL)
Founder of the Western Electric Manufacturing Company: fought (and lost) a legal battle with Alexander Graham Bell over the rights to the patent for the telephone in 1876		Elisha Gray
The first operational steam turbine was built by		Sir Charles Parsons
Catch Me Who Can was the fourth and last steam railway locomotive to be created by		Richard Trevithick
Inventor of the seed drill (a sowing device that positions seeds in the soil and then covers them – an important advance in the Agricultural Revolution)		Jethro Tull
French inventor (1631) of a scale for precise measurement of a distance or angle, named after him		Pierre Vernier
English engineer and entrepreneur (born in Stockport), devised the first standardised system for screw threads		Joseph Whitworth

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