Lobster wrote:
Rod wrote:
Chewbacca wrote:
tony sayer wrote:
In article , Dave Plowman (News)
scribeth thus
In article , Bill
wrote:
There is, of course the ancillary question about why, if it's
a condensing boiler, we see so much 'steam' from it. If it
were condensing fully, surely we should see no visible
exhaust.
It's water vapour - not steam.

Woss the difference then?...

Steam is a gas and invisible. You can sometimes not see it - as it
is invisible - a mm or 2 above the kettle spout when boiling hard.
Above this you see the foggy stuff we all call steam. Actually
this is tiny particles of liquid water - the steam has condensed as
water droplets - that are so small they float about in the air.
Being hot water they tend to evaporate and disappear.

I (along with, I assume, many of the people here) have been using
that approach since I was knee-high to something or other. But is it
a tenable approach? If, as you say, it is what "we all call steam",
then perhaps it is the definition of steam that requires revision to
accord with real language use?

I get the feeling that the clouds of water droplets emitted by most
steam vehicles have at least made that a reasonably sensible meaning.

That's probably why the word "steam" is used for "what we all call
steam" isn't it: originally (and indeed, still) a steam engine is an
engine which is powered by steam, but in common parlance became one
which produces copious quantities of "steam".

FWIW, this from the Oxford English Dictionary

steam, n.
6. a. The vapour into which water is converted when heated. In
popular language, applied to the visible vapour which floats in the air
in the form of a white cloud or mist, and which consists of minute
globules or vesicles of liquid water suspended in a mixture of gaseous
water and air. (Also sometimes applied to the vapour arising from other
liquids when heated.) In modern scientific and technical language,
applied only to water in the form of an invisible gas.
The invisible ‘steam’, in the modern scientific sense, is, when its
temperature is lowered, converted into the white vapour called ‘steam’
in popular language, and this under continued cooling, becomes ‘water’
in the liquid form.


So it would appear that the lexiconographers have already taken heed of
your comment!

David

Thank you!

Also see:

http://en.wiktionary.org/wiki/steam

The picture on the right ("Steam rising from the street grates.") seems
to go down the same direction - but whether out of ignorance,
carelessness or something else, who can tell? :-)

--
Rod

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