Ever notice that electricity flows backwards?
In a flow of electricity, electrons carry charge from the negative to the positive. (Actually, it's more complicated than that, but the complication is irrelevant to the point.) You'd think that the people who named the electrical poles (most likely, Benjamin Franklin) would have known things flow from a positive to a negative. Which would have ultimately resulted in the electron - after its discovery much later - being designated as holding a positive charge.
However, those early experimenters had no idea how electricity was carried. They could produce a flow and measure its effects, and agreed on what to call the poles they found. Only later was the direction of charge travel actually determined. We can't reasonably blame them for getting it wrong, or actually even seriously consider that they got it wrong. They made the best choice available to them and set the standard, and that is what we use. However, the existing convention still causes trouble for some people.
The corresponding labels for Magnetism, at least, make sense, though you have to remember the reason behind them. They're based on long-standing names for parts of the Earth and directions towards them. The north pole of a magnet therefore has the same polarity as the Earth's South Pole, because it points North. This is something anyone who understands that the Earth has a magnetic field can also understand.
I'm an engineer. Any competent engineer knows the importance of proper use of terminology. Because when we engineers are careless with it in a professional capacity, things tend to fall down. Being a bit obsessive-compulsive on top of that, one of my pet peeves is misuse of words and terms.
For example, ever notice how some folks use "literal" and "virtual" exactly backwards? Either error makes me gnash my teeth. However, there are far more important reasons than personal irritation to be careful about what you say.
Terminology is important, especially terminology which allows us to abbreviate. Using the right short word or abbreviation in the proper context can save us from repeatedly giving long descriptions of what we mean. Saying "chip" instead of "microprocessor circuit assembly on a single substrate chip" or even "microchip" saves a lot of time and effort. However, if you say "chip" in some circumstances without elaboration folks won't know whether you mean "microprocessor circuit assembly on a single substrate chip" or "chocolate chip." As usual, context is very important to meaning in language, whether spoken or written.
It's not just engineering and the physical sciences which require precise terminology, either. Paleontologists seethe quietly - and sometimes not so quietly - when the media or popular culture lump all prehistoric reptiles together as "dinosaurs." That word actually refers to a specific group of creatures distinguished from other reptiles - past and present - by shared characteristics.
This isn't just people being picky. These distinctions are important because the differences they point out are significant. Even when - as with electricity, electromagnetism and electromagnetic energy - the specific terminology is an accident of history, not adhering to the accepted terminology can result in confusion. Any competent engineer will tell you that when a standard exists - even an arbitrary one - you should use it, unless you have a good reason not to. Unfortunately, the exact same term can mean different things in different professions. Again, context is often essential.
By the way, an electromagnet is a magnet which only works when you put electricity through it. Electromagnetic radiation is something different. It received its name because it has some characteristics of both electricity and magnetism, even though it is something distinct from both of them. Because magnetism, electricity and electromagnetic radiation are all closely connected you can easily convert between them. Further adding to the confusion.
Your life could depend on precise and accurate labeling. Saying "gas" when you mean "gasoline" is acceptable when you're talking about vehicles or liquid fuels. However, if you're talking about atmospheric contaminants this could lead to confusion. "You need a filter mask. There's gas fumes in there." A mask for keeping out gasoline vapor might not work against methane (natural gas) and vice-versa.
Even in situations where the literal meaning of the words used to describe something are accurate for the field, there can still be problems if the particular field isn't known. This is especially troublesome when different fields use the same words for very different things. When an astronomer recently published a paper on "a new taxonomy for asteroids" referring to those lumps between Mars and Jupiter, he got multiple requests for copies of his paper from marine biology departments... because "asteroid" is the technical term for starfish. (The word in Latin meaning "star like.") Yet again, context is vital!
So, you think you know what plasma is? To a medical person it is something quite different from what a physicist expects. Neither usage is exactly true to the original Greek meaning! (Books could be written on the problems caused when the person who names something has an incomplete understanding of Greek or Latin.)
In physics, a plasma is a state of matter in which the electrons have been stripped away from the atomic nuclei they normally circle. It is like a gas, only moreso. The word was adopted to describe this state in 1928.
In medicine, plasma is the fluid which carries the other components of blood. Only, it is also the fluid inside cells, or the fluid inside cellular nuclei, or... This usage was adopted in 1845.
The etymology of plasma - or plasm, to get a little closer to the original - is rather interesting. In the original Greek it means something molded or created, or something spread thin. You can see how it applies to both areas of current scientific usage.
One of my really hot button pet peeves is the phrase "dark side of the Moon."
Now, when it's being used in a poetic or metaphorical sense, as Pink Floyd did, that's fine. However, when someone uses it literally that makes my teeth ache. Because unless they're an astronomer or planetologist or an amateur interested in those fields, they are pretty much guaranteed to get it wrong.
You see, what part of the Moon is dark changes on a monthly cycle. Unlike the near and far sides, which never change, because the Moon is tidally locked to the Earth. Anyone who knows the Moon has phases knows that the lit part changes on a regular schedule. Yet they keep saying "dark side" usually to mean the far side.
Sometimes, lay people inexplicably perpetuate an archaic or incorrect usage long dropped - or never used - by professionals. Take the word "galaxy." The word derives from the Greek term for our own galaxy, galaxias, or kyklos galaktikos, meaning "milky circle" for its appearance in the sky. Also known as the Milky Way, our galaxy appears as a dense, bright band in the night sky, resembling spilt milk.
Once the telescope came into use, Astronomers quickly found some rather distinct "spiral nebulae" in the sky, and wondered over their nature. By the early Twentieth Century they were known to be groups of stars, and thought to be something similar to various globular and irregular clusters, and assumed to be part of the Milky Way like all other stars. However, that didn't quite fit new data coming in. Eventually, distance measurements and improved mapping of the Milky Way combined to show that these "nebulae" were actually "island universes" vastly more distant than the clusters of stars of the Milky Way. Further, they found that the closer stars in that formation are arranged in a complex shape resembling the "spiral nebulae."
This meant that not all stars were together in one, vast group, the Milky Way. Instead, there were multiple Milky Ways, or island universes, one of which we reside in. Due to the ancient Greek myths attributing the spray of stars making up our island universe with the spilled breast milk of a goddess, "galaxy" came to be the general term for large, gravitationally bound aggregations of stars separated from each other by vast distances. "Island universe" is still occasionally used, but normally in a deliberately archaic sense.
However, for some reason, certain laymen can't seem to understand just what a galaxy is. Nearly a century after astronomers got things straight, these people use "galaxy" to mean our solar system (or, more rarely, another stellar system). The origin of this mistake is not known to me, but it seems to be about as old as the modern definition of galaxy.
Time designations such as 12 AM or 12 PM are nonsense. You see, AM means ante meridian, or before Noon. PM means post meridian, or after Noon. Saying 12 PM for Noon is like saying "twelve Noon after Noon." You could almost make a case for 12 Midnight, but since it is equal amounts of time before or after Noon, is it AM or PM? We have correct and distinct terms for these times. Why go out of the way to say something not only not the standard, but confusing?
Now, yes, usage changes, as do standards. However, when careless usage results in something which isn't really useful, it's not creating a new standard. It's creating confusion. Like saying "Eighteen Hundreds" when meaning "Nineteenth Century." The Eighteen Hundreds were actually 1800 to 1810. (Or maybe 1801 to 1810. Or 1801 to 1811. Or 1800 to 1811. This is a gray area.) Using a term which has a long-understood - if not precise - definition to mean something else is careless at best and folly at worst.
By the way, stainless steel isn't. Bulletproof isn't, either (someone always has a bigger bullet). "Almost infinite" is an oxymoron. Totally unique is redundant. Penultimate does not mean "more than ultimate." And on and on...
This document is Copyright 2011 Rodford Edmiston Smith. Anyone wishing to repost it must have permission from the author, who can be reached at: firstname.lastname@example.org