Spark, no oxygen?

Raist said:
Proof is in the ceiling? :D

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lightbulb a contains gas and b contains no spark just white hot glowing metal.

spark needs a gas to travell across but not necesarily oxygen. ie it would work in co2?
 
laiman said:
lightbulb a contains gas and b contains no spark just white hot glowing metal.

spark needs a gas to travell across but not necesarily oxygen. ie it would work in co2?
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Yep, any gas. :)
 
laiman said:
lightbulb a contains gas and b contains no spark just white hot glowing metal.

spark needs a gas to travell across but not necesarily oxygen. ie it would work in co2?
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Lightbulb B has glowing metal due to sparks jumping around it continuously (electrical arc).

I believe CO2 would glow given the proper electrical charge and (compression?), but doesn't work as well as the other noble gases.
 
Best thing I have ever seen is a load of balloons full of all the different types of Noble Gases. You can throw one full of Xenon at someone and it ****ing hurts. :D
 
NicktheNorse said:
are bullet cartridges air tight?
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I would say they must be to ensure that all the thrust is forced directly behind the bullet. If the casing wasn't air tight the thrust could just leak out around the casing.
 
Bullets do not have to be air tight, Althogh it does help. .22 rounds are not air tight, as there is play in the bullet and the casing. Remeber also that the force of the explosion makes the bullet expand laterally, thus helping the effect of rifleing.

A Spark of hot metal, flint or an electrical spark CAN occur in a zero oxygen environment. Case Closed :)
 
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If you mean totally air tight - then no....
If you kept a bullet in a true vacuum (as in a pressure less then 10-8 to 10-10 Torr, which is what most of my turbomolecularpumps work at) for more than an hour say, it would loose all of its oxygen molecules - so wouldn't spark or fire.... Even a 2mm thick sealed glass bulb has leakage in a vacuum. Any vessel at total vacuum will evetually leak to even out the pressures.

But yes - it would spark, but only if the combustion took place before the gas escaped, or the ataoms escaped out or leaked in....... depends on the seals - the materials in the walls of the vessel (most alloys / materials allow atoms to escape eventually) the strength of the vacuum and the mixture of gases it was ignited in.

I spend on average 10 hours a week doing leak checking tests on high vacuum machines and tools which operate at 10-9 Torr......so ask away ;)
 
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divosuk said:
Even a 2mm thick sealed glass bulb has leakage in a vacuum. Any vessel at total vacuum will evetually leak to even out the pressures.
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Surely the bulb would explode due to the extreme pressure gradient across the glass?

So what are we saying - could a revolver be fired in a vacuum? Dont worry if its a perfect vacuum or not - say an astronaut on a space walk were to fire a gun.....

edit: whats a torr?
 
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Moredhel said:
A torr is a unit of pressure. And we're saying a gun could be fired in vacuum at first, but not after a while.
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ok.

I happen to know a fair bit about "pressure," but never heard of a torr! is it an imperial measure? how does it relate to say, pascals?
 
Torr is a measure of pressure....same as Pascals, Bar and PSI.

info

Space is about 10-15 to 10-16 Torr. Machines I work at operate at 10-10 (-0.0000000001 Torr) and take 24 hours to pump down using turbomolecular pumps -almost total vacuums - and a lot less atoms than most things on earth.....Atmosphere (or air at sea level) is approx. 760 Torr.

And in answer to the question - a gun would fire (if it were in a vacuum for say less than an hour)....any longer, and the combustible gases in the cartridge would leak out and render it useless.
 
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divosuk said:
Torr is a measure of pressure....same as Pascals, Bar and PSI.

info

Space is about 10-15 to 10-16 Torr. Machines I work at operate at 10-10 Torr and take 24 hours to pump down using turbomolecular pumps -almost total vacuums - and a lot less atoms than most things on earth.....Atmosphere (or air at sea level) is approx. 760 Torr.

And in answer to the question - a gun would fire (if it were in a vacuum for say less than an hour)....any longer, and the combustible gases in the cartridge would leak out and render it useless.
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cool, cheers :)
 
Unless of course you were very clever and made a gun with a solid or liquid oxidising agent in the cartridge which caused an explosion via oxidisation. :p
 
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