I've always wondered...

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userjjb
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Sat Aug 18, 2007 12:21 am

Gepard wrote:
userjjb wrote:snip>Water vapor is transparent to the naked eye <snip>
Surely not as otherwise we wouldn't see clouds.
Michael
Actually water vapor is indeed transparent, what people typically call "steam" (for instance when water boils) is actually not vapor at all, but rather small condensed water droplets. Clouds are made out of these water droplets and so we can see them. If water vapor was opaque we wouldn't be able to see anything at all because the atmosphere contains around 1% water vapor. When you fire a pneumatic the gas in the chamber rapidly expands cooling it down. This causes the water vapor to condense into visible liquid water droplets.
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joannaardway
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Sat Aug 18, 2007 8:10 am

Actually, it's the other way round.

Steam is perfectly invisible with a refractive index of 1, but condensed water vapour is merely transparent, having a refractive index of about 1.3, which means it bends the light that travels thorugh.

Humidity in the air is by a definition, steam - water in gaseous form, not at over 100 degrees, but "boiling" nonetheless.
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userjjb
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Sun Aug 19, 2007 4:46 pm

joannaardway wrote:Actually, it's the other way round.

Steam is perfectly invisible with a refractive index of 1, but condensed water vapour is merely transparent, having a refractive index of about 1.3, which means it bends the light that travels thorugh.

Humidity in the air is by a definition, steam - water in gaseous form, not at over 100 degrees, but "boiling" nonetheless.
Right that's what I mean, which is why I said "what people typically call 'steam'" People often confuse real steam or water vapor with condensed water droplets (like from breath when it's cold or in our case from rapidly expanding air).
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Pilgrimman
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Sun Aug 19, 2007 6:01 pm

Wow! I didn't expect this many replies! I've read them, and the one that would make the most sense to me is the sensory overload one. I was worried more about watching where I was shooting than about what was going on at the muzzle. However, the others are, for the most part, plausible. Feel free to keep speculating, and thanks for the help!
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Rudesill Ballistics
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Tue Sep 04, 2007 10:47 pm

I noticed it when my LSK had a ball valve, and when it had a sprinkler there was less.

In my tests of my piston today I didn't notice any cloud what so ever.

I honestly missed it. :(
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