"Scientifically, its coefficient of thermal expansion from 0-300°C is a mere 33.9 x 10-7 per ° C"
Scientifically you need to say 33.9*10^-7 WHAT per degree C, presumably not light years or furlongs. Come on get with it :)
One of the key brand names tossed around in relation to smartphone and tablets this year has been Corning's Gorilla Glass. Next year, it may be Lotus Glass. Corning announced Lotus' commercial availability yesterday, and immediately began touting the display material's suitability for "cutting-edge technologies", including …
I was astonished to see 33.9 * 10^-7 when the usual notation would be 3.39 * 10^-6.
Especially since 10^-6 is a conventional point of reference usually denoted by 'micro'.
As to the 'What' per degree C, it is just a proportion of the length (or volume for liquids), which in this case is specified for not just one temperature (usually 20C) but the whole 0-300C range.
Some comparisons for other materials here - https://secure.wikimedia.org/wikipedia/simple/wiki/Coefficient_of_thermal_expansion
> Scientifically you need to say 33.9*10^-7 WHAT per degree C
...But I seem to remember thermal expansion coefficients being fractional changes, and thus dimensionless...
[Who's going off to check, just in case he's just made a total arse of himself. Again.]
It's a coefficient, not a unit. You could determine it experimentally by measuring the length (or volume) of a piece of the material at one temperature, and then again at another temperature, and then divide the two measurements. Because you are dividing the same units the resulting ratio has no units. If you then divide it by the temperature difference you get the coefficient, whose unit is "per degree C". Hence "33.9 * 10^-7 / degree C".
If I may divert the conversation slightly:
While I'm here: "Panini" = "Sandwiches", not "Sandwich". The singular form is "Panino".
Every time I pass some pretentious café or glorified sandwich shop in England and see "panini" used as a singular noun, I want to beat someone repeatedly over the head with a copy of "Il Ragazzini". It's not _that_ hard to look something up in a dictionary. Or even to ask a translator (or, hell, even someone who's bilingual!)
Then again, I twitch every time I see a grocer's apostrophe, so maybe I should get out more.
There is no "WHAT" required, this is a coefficient, it works in any system of units.
(Saying miles per mile per degree Celsius, or metres per metre is redundant.)
However, the author did fail to tell us whether this was a linear, area or volume coefficient, but I'd guess that this is its linear coefficient of expansion, judging by it's size.
... the version marketed with "Energy, style, and enthusiasm" - Lotus Elan
Then the one that does it's job a bit better that the original - Lotus Excel
Then the on that's so thin it's a ghost of the first version - Lotus Esprit
Then the one for iPhone only - Lotus Elite
Any resemblance to Lotus Cars is purely coincidental, unless they actually use this stuff in the new Lotus Esprit, over the engine bay to show off the nice new V8. Or possibly in houses in Évora...
If you're being pedantic, it's 33.9 x 10-7 metres per metre per ° C
If you're being really pedantic the metres cancel out and leave you with 33.9 x 10-7 per ° C
So, yes, light years or furlongs would be fine. As would linguini. If you want linguini per furlong per ° C then the number itself is going to change though.
The units of the coefficient of thermal expansion are length per length per Kelvin - therefore just per Kelvin (or per degree C, if you prefer). This one means that per degree C it expands by 3.4 millionths (of its original size). Not quite sure why this was expressed with the exponent -7 though.