[Sean Holden]

Sean Holden  asked the Naked Scientists:

Hello, my name is Sean and I have a question I need an answer to.

If I were to light a match from a match box in space, although there would be no flame because there is no oxygen to start a fire, would the flint of the match still ignite?

If you can answer this I would be very grateful.

Its driving me mad!

Seanist

What do you think?

[Soul Surfer]

It should be possible to light a strike anywhere match in space because the head is essentially a firework and contains both fuel and oxidiser but the match would quickly go out once the oxidiser was all used up and the wooden stick would not burn.

Lighter flints would probably not spark in space because the small metal particles need oxygen in the air to glow brightly however a fast grindstone grinding steel may produce rather dim sparks because the particles of metal ripped off by the grindstone are initially red hot but they cannot burn in space.

[lightarrow]

It should be possible to light a strike anywhere match in space because the head is essentially a firework and contains both fuel and oxidiser but the match would quickly go out once the oxidiser was all used up and the wooden stick would not burn.

Lighter flints would probably not spark in space because the small metal particles need oxygen in the air to glow brightly however a fast grindstone grinding steel may produce rather dim sparks because the particles of metal ripped off by the grindstone are initially red hot but they cannot burn in space.

Very good answer Ian.

[lyner]

I was thinking about this; to get the particles of steel hot enough to ignite in the first place, they would need to be glowing brightly due to the  striking, so they must start of bright even before any combustion takes place. So I say that there would be sparks, visible, but not so long -lived as there would be in air. There is another factor: in a vacuum, the cooling effect would be less than in air and that could affect how long the trails of hot, 'unignited' steel particles appeared to be.

[lightarrow]

I was thinking about this; to get the particles of steel hot enough to ignite in the first place, they would need to be glowing brightly due to the  striking, so they must start of bright even before any combustion takes place. So I say that there would be sparks, visible, but not so long -lived as there would be in air.

I'm sure that a red-hot particle is hot enough to start a fast combustion in air, so I don't think it's necessary for it to be very brightly glowing at the beginning.

There is another factor: in a vacuum, the cooling effect would be less than in air and that could affect how long the trails of hot, 'unignited' steel particles appeared to be.

This is certainly true but, how much? I suspect that the heat transfer through radiation, at those temperatures and for those tiny particles, exceeds a lot the one through conduction with air.

[lyner]

You could be right about the fast combustion; as they are moving fast through the air they have a 'forced draught', effectively. It all depends upon what the minimum temperature is for steel to burn.

[lightarrow]

You could be right about the fast combustion; as they are moving fast through the air they have a 'forced draught', effectively. It all depends upon what the minimum temperature is for steel to burn.

Don't know, however you can ignite steel wool with a candle flame; you see it becoming just red hot and then it continues to burn by itself; if you move it rapidly (e.g. you fix it to a long thread which then you rotate fast), the air flows quicker and it becomes much brighter and white hot, also sparkling.
http://it.youtube.com/watch?v=ElqYJ654eq4

[lyner]

Have you seen those new magnesium alloy / steel firelighters? They produce a fantastic shower of sparks when struck right. You can get a fire going with virtually no 'backwoods' skills at all - it's like a blow torch for a brief period. It would be interesting to try it out in an inert atmosphere -nitrogen, for instance- and see the 'glow'.

[lightarrow]

Have you seen those new magnesium alloy / steel firelighters? They produce a fantastic shower of sparks when struck right. You can get a fire going with virtually no 'backwoods' skills at all - it's like a blow torch for a brief period. It would be interesting to try it out in an inert atmosphere -nitrogen, for instance- and see the 'glow'.

Interesting, I didn't know it. Do you have some more informations?
However, if Mg were in high percent (but it's unprobable), then even a nitrogen atmosphere wouldn't be exactly inert, even if it certainly wouldn't allow for a real combustion. When you burn Mg metal in air, infact, you get white MgO and a not-low percent of gray Mg₃N₂ as a result of high temperature Mg combining with N₂. (Just to be nitpicking.  [])

[lyner]

high temperature Mg combining with N2

Well, you live and learn.

You can buy these things in camping / out door shops everywhere in the UK. Very impressive. Treat yourself to one and experiment; they're cheap enough.

[lightarrow]

You can buy these things in camping / out door shops everywhere in the UK. Very impressive. Treat yourself to one and experiment; they're cheap enough.

Thanks!