![]() And nanization is the English word for the process of producing a bonsai tree-the deliberate production of a dwarf plant. ![]() Nanism is a state of dwarfishness, a term applied to the evolutionary change in the size of species at high latitudes or on remote islands. (In the case of the picometre, a very little over two metres.) Pico- seems to have been in general use for some time before 1947-the Oxford English Dictionary has an example of its use from William Eccles‘s Wireless Telegraphy and Telephony from 1915, whereas all the others have their first citation from the Proceedings of the 1947 Union Internationale de Chimie conference. So dos metros y pico is “a little over two metres”. Pico is the Spanish word for a mountain, and for a bird’s beak. The odd one out is pico-, which is Spanish. These new prefixes are all Greek but one. Along with mega- and micro-, this set a useful precedent for multiplier prefixes to end in “a”, while fraction prefixes end in “o”. (I suppose they took a particular interest in the matter because chemistry deals fairly regularly with very large numbers of very small things.) At their fourteenth conference they adopted the following prefixes: giga- for 10 9 and tera- for 10 12 nano- for 10 -9 and pico- for 10 -12. The next additions came in 1947, from the Union Internationale de Chimie. The smaller fractions and multipliers were still useful enough to be kept in regular use, but myria- languished and died before the nineteenth century was over. In powers of ten that goes 10 3, 10 6, 10 9 …, and 10 -3, 10 -6, 10 -9 … I’m going to need to use that notation from here on in. And maybe it’s worth mentioning that microwaves are just “small waves”-their wavelength is short in comparison to radio waves, but still measurable in centimetres or millimetres, not micrometres.Īfter the adoption of mega- and micro-, the idea grew that we need a new prefix at each new integer power of one thousand-thousandfold, millionfold, billionfold, and so on up thousandth, millionth, billionth and so on down. Megas also gave us the medical suffix -megaly, meaning “enlargement”- acromegaly, enlargement of the extremities (the hands and feet) hepatomegaly, a swollen liver. There are so many words in micro- and mega- that even I am not tempted to try to list them. The word microscope, for a device to look at small things, had been around since the seventeenth century the less well-known megascope was a nineteenth-century projecting microscope-it threw an enlarged image on to a screen, where it could be traced and turned into a drawing. And both prefixes had already been doing duty in the scientific vocabulary to designate big things and small things. ![]() Mega- comes from megas, “big”, and micro- from micros, “small”. In future, care would be taken to avoid producing more than two prefixes with the same initial letter.īoth mega- and micro- are Greek, which upsets the original system of using Latin for fractions and Greek for multiples. But for micro-, the Greek lower case letter mu (μ) had to be recruited. Mega- was distinguished from milli- by the use of its capital initial (“M”) establishing a precedent for all the multiplier prefixes above kilo. This created an abbreviation crisis-there were now three prefixes beginning with “m”. The new prefixes were mega-, for a millionfold multiplication, and micro-, for a millionth part of the base unit. ![]() The next two prefixes were introduced as part of the definition of the electrical units of measurement, by a committee set up in 1861 by the British Association for the Advancement of Science, under the leadership of Lord Kelvin and James Clerk Maxwell. In the last century we’ve added prefixes only for integer powers of one thousand. There was also a realization that there didn’t need to be a prefix for every power of ten-that would get unwieldy very quickly. Inspired though the original system was, it didn’t offer enough range for scientific use, and the collection of prefixes has been steadily growing. Part 2 dealt with the multipliers- deca-, hecto-, kilo- and myria-, for tenfold, hundredfold, thousandfold and ten-thousandfold multiplication. Part 1 dealt with those original fractional prefixes- deci-, centi- and milli-, designating a tenth, hundredth and thousandth part of the base unit. In my first two posts about the SI unit prefixes, I described how the system originated in the French Republican metric system of 1795.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |