Common misconceptions, misnomers and misuse

Make sure you're not misconceived

AM/FM

AM and FM describe the modulation of a radio wave not its frequency or wavelength. The 'AM band' is actually MW (medium wave) or mf (medium frequency) and the 'FM band' is actually band II VHF (in the UK at least).

Seal/Sea Lion

People keep calling sea lions (the animals which ballance balls on their noses in circuses) seals but seals are the rather less athletic animals which get hit with clubs.

Mass/Weight

Kilograms measure mass not weight. Weight is a force measures in newtons.

Celsius/Centigrade

The temperature unit which should be used for weather reports is the degree Celsius (not Celsius, degree Centigrade or Centigrade). The degree Centigrade is the unit of the Centigrade scale which is not necessarily linear and not necessarily the same as the Celsius scale. A particular Centigrade scale is proportional only to a particular physical attribute. So there is a Centigrade scale which is proportional to the length of a water column and another which is proportional to the volume of a particular gas plus as many others as you can invent.

Kelvin

The kelvin is the SI unit of thermodynamic temperature. It is not the 'degree' kelvin. Plenty of scientists get this wrong as well.

SI Units

SI units are lower case even if they are named after someone. So in the middle of a sentence the unit is a newton but the man himself was Newton.

Mr Spock

The guy on Star Trek was Mr Spock (not Dr Spock who was a child psychiatrist or something like that).

Sound cards with a 32 in them

The Sound blaster AWE32 doesn't do 32-bit sound, it has 16-bit sound like the SoundBlaster 16 and 32 voices.

Silicon/silicone

Silicon is the metallic and semiconducting element. Pure silicon looks like a shiny solid metal. Silicone is a silicon compound used in grease, implants, etc.

Bela Lugosi

Bela Lugosi didn't die during the making of Plan 9 from Outer Space - he died before it was made. And the writer's chiropracter was used as a stand in (not his wife's dentist).

Meteor/Meteorite/Meteoroid

A meteor burns us in the Earth's atmosphere leaving only dust.
A meteorite gets through the Earth's atmosphere to hit the surface.
A meteoroid is either of these while still in space.
Meteor Crater, Arizona is therefore a misnomer.

Gravitational Assist

Vehicles using gravitational assist don't take energy from a planet's gravity but from its angular momentum. The planet will have a slightly different orbit after such a flyby.

Seconds

The SI abbreviation for the second is s not sec or anything else.

Apostrophies

There shouldn't be an apostrophie after a plural abbreviations like:
In the 1980s
There are 10 CCDs.

Voltage

You have 100V across something not flowing through it. Current flows through something.

Abbreviations

Beware of writing things like personal PIN number (personal personal identification number number!)

Shock absorbers

Bit of a misnomer: the springs are the things that absorb the shock and the 'shock absorbers' are dampers.

Zero G

There is still a gravitational attraction to something in orbit so the acceleration due to gravity 'g' is not much less than on the surface of the Earth. An orbiting object is in free-fall though which gives the appearance of no gravitational attraction.

Quotations

Is it 'Let loose the dogs of war' or 'Let slip the dogs of war'?

Wherefore

Wherefore means 'why' not 'here'. So when Juliet says, "Wherefore art thou Romeo," she's saying, "Why are you called Romeo," because if he had a different family name they'd not have had all that trouble.

Yorik

The quote is, 
	Alas, poor Yorick! I knew him, Horatio: a fellow
	of infinite jest, of most excellent fancy: he hath
not "... I knew him well".

Animals

People often say 'insects and animals' or 'animals and man'. They should say, 'insects and other animals' and 'man and other animals'. Insects and man are animals; whales, dolphins and man are mammals and animals; sharks are fish and animals, etc.

Comets

Comets move very slowly across the sky. They are often portrayed (especially in films & TV) as moving across the sky in seconds to minutes when they actually take months.

Malnutrition

People often use the work malnutrition when they mean undernutrition. Malnutrition means eating a bad diet and undernutrition means eating too little. Though I suppose eating too little is also bad.

Light Years

A light year is a measure of distance (some think is is a measure of time). A parsec is also a measure of distance (not time as in 'Star Wars'!).

Canberra

Canberra is the capital of Australia not Sydney.

Water down plughole

Water is meant to spin in a certain direction down a plughole in one hemisphere and the opposite direction in the other hemisphere because of the Coriolis Effect. In fact, small disturbances in the water grow as the water leaves and it ends up spiraling in a random direction.

RTGs

Radioisotope thermal generators die not when their radioactivity has decreased below a useful level but when their thermopiles come to the end of their lives.

UK

The UK includes Nothern Ireland, Great Britain does not. The British Isles includes all of Ireland.

Phenomena

Phenomena is a plural. Phenomenon is the singular.

Criteria

Criteria is the plural. Criterion is the singular.

Latin Plurals

You don't just add 'i' or 'ii' onto the end of a Latin word to make it a plural.

Apollo 13

People say, "Houston, we have a problem" but the actual words were:
"OK Houston, we've had a problem here."
"This is Houston. Say again please."
"Houston, we've had a problem."
(see http://history.nasa.gov/Timeline/apollo13chron.html).