gas laws apply to gasses, not liquids. when a substance changes state, you
ca't continue to apply the gas laws to them - a liquid is not just a
compressed gas, it's a different kind of matter. Water is a liquid. if you
heat it, the water absorbs heat and eventually turns to steam (heat of
evaporation) - if you extract heat, it turns back to water (condensation),
and if you extract even more heat, it becomes ice. so, in a way your wife
is right - it does violate the gas laws because the state change makes the
substance no longer a gas.

here are some links
http://hyperphysics.phy-astr.gsu.edu...rmo/phase.html
http://www.thirteen.org/hawking/myst...gleiser-3.html
http://www.lbl.gov/abc/wallchart/tea...pdf/Chap09.pdf
http://www.chemistry.wustl.edu/~edud...em/Fridge.html
http://rabi.phys.virginia.edu/HTW/water_steam_ice.html

"K. James" dood@nowhere wrote in message
news:famGd.8959$OF5.451@attbi_s52...
I've been lurking here for years, but I seldom post. Learned a lot
though.
Apparently not enough.

Now I've come before the font of collective wisdom, hat in hand.



I made an offhand remark to SWMBO that I'd like to build a fire piston.

"And that would be...?"
"Method of starting fires. Works on compression, sorta like a Diesel."

Blank Stare.

Well, me bein' typically full of refined oats, I proceeds to expound upon
the principle. Yep. Uh-huh. So I sez...

"Ya know about the gas laws, right? Ya know, Bernoulli, Boyle, and
prob'ly
a couple other dead guys? 'Member the part 'bout compressin' gasses
gettin'
hot and expandin' gasses gettin cold? Like that."

So she sez,
"I have a question."

Now, I figger that I can field any technical question posed by a mere
female
without blinkin'.

"Shoot."
"Water."
"Huh?"
"Water."

Blank Stare.

So she sez,
"Water exists as a liquid and a gas, right?"
"Yeeesss...Kind of. I think. Not sure that steam is a *gas* exactly,
but..."
"Well, water is steam in a compressed state, right? And you heat water to
make it expand into steam, right? And when steam cools, it condenses back
into water. So wouldn't that violate the gas laws?"

Great Big Googly Eyed Blank Stare.

"Uh, well technically, no, but ah, state change uses energy, and
thermodynamics and stuff like that there, and uh, yes, violations, no
uhhh, kinda, sorta......ahem. Umm."

Blast. And damn if she ain't hidin' a grin up her sleeve.

Any you fellas what has had the benefit of a real education want to chime
in
with the answer?
Heck, I'm not 100% sure I even know what the question is!

I have a sort of vauge idea, but I can't find words to express it.

And she's still hidin' that grin.

TIA

Kenneth James