Sciencemadness Discussion Board

Matches

DFliyerz - 15-2-2015 at 18:58

I tried looking on Google, but it didn't want to give me an answer, so here's my question: why does a match flare up more and hotter when you light the match head on fire with another flame instead of just striking it? I can use a match head lit on fire with another flame to ignite my fairly-well-powdered thermite mixture, but not just the flame from a match that was lit a second or two earlier.

Zombie - 15-2-2015 at 19:20

Just a common sense guess? you are removing some of the compound from the match when striking it as well as transferring some compound from the striker.

Otherwise nothing else has changed.

DFliyerz - 15-2-2015 at 19:55

Quote: Originally posted by Zombie  
Just a common sense guess? you are removing some of the compound from the match when striking it as well as transferring some compound from the striker.

Otherwise nothing else has changed.


That's not quite the question, it's sort of hard to put in words. When you hold a flame to the unlit head of a match, it flares up more powerfully than when you just strike it. Why is that?

Bot0nist - 15-2-2015 at 20:11

It "flares up more" because when the open flame is applied to the match head it ignites more of the pyrotechnic mix (KClO <sub> 3 </sub> and sugar?) at once. When you use the striker (red phosphorus and abrasives...) the ignition begins at a very small point, and then spreads.

Edit:
Even if you were to not engulf the match head in flame, but instead hold the match head at a slight distance from the open flame in an attempt to reduce the surface area of the point of ignition, the radiant heat from the open flame would still heat up/partially melt the surface of the pyrotechnic mix, making the flame spread much faster, than if the heat began at a single point, as from friction against the striker.

[Edited on 16-2-2015 by Bot0nist]

Bert - 15-2-2015 at 23:54

FYI: Match compositions-



image.jpg - 116kB

jiexiang88 - 16-2-2015 at 06:25

Basically when you strike a match, only a tiny part ignites, causing it to take some time before the whole match ignites. But it placed on a flame, the whole outer surface of the match is ignited all at one, causing it to look "hotter".(basically rephrasing what Bot0nist said) :)

Metacelsus - 16-2-2015 at 08:13

Also, with a flame, the match will be preheated prior to ignition, thus increasing the burn rate even more.

Bert - 16-2-2015 at 13:40

There is more total heat energy in the system by the amount provided as activation energy transfered from the first match to the second.

The heat energy of the second match is released in a shorter time as well-

Net result: More energy, and released faster.

Deathunter88 - 27-3-2015 at 08:57

Quote: Originally posted by DFliyerz  
I can use a match head lit on fire with another flame to ignite my fairly-well-powdered thermite mixture, but not just the flame from a match that was lit a second or two earlier.


I think it is because the composition burns hotter than the wood(or cardboard) so you can use the heat of when the match head to light the thermite but once it is used up and only the wood is burning then it cools and is not nearly hot enough.

jock88 - 27-3-2015 at 12:06


The outside flame would also heat the match heat which will give bigger flare up.

If you take a match and instead of striking it off the box, take the match and 'screw' it into the striker (try to bore a hole in the striker using the match).
When you do this the match (for some reason or other) will ignite with a loud crack sound.

Hellafunt - 27-3-2015 at 13:13

www.youtube.com/watch?v=_074G_bk5sY

this shows a match lighting incredible slow motion

hissingnoise - 28-3-2015 at 03:45

Indeed, and the old strike-anywhere matches would part fulminate when heated slowly to the point of ignition!