Science Questions

Why brief contact with a flame doesn't burn?

Sun, 12th Oct 2008

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Question

Andre asked:

Why can a finger be passed through a flame and not burn?

 

Answer

Kat - This is a fascinating thing to see. The first time I saw this done was by my vicar at church. I really thought, 'This man has come from God!' It was very impressive! The Blowing out a candlething behind this is that basically candles aren't that hot. The other trick is to do it fast and through the right part of the flame. You need to know a little bit about how candles work. It all boils down to convection, heat rises. The top of the candle is much hotter than the bottom of the candle. If you ever try holding your hand over the top of the candle you find out extremely fast it's very, very hot. It's about 600 degrees. You can actually pass your hand through the bottom of the flame because all the hot air is rising up the bottom of the flame is where all the cold air from the room is being sucked in. The bottom of the flame is quite cold. You can stick your hand through, get a bit of soot on it. You can do that so long as you do it at quite a quick speed, especially if your fingers are a bit wet. Then you'll just burn off the water rather than burning your hand.

Chris - Great, so now you can go and impress your mates with that but don't try it with a blow-torch or something!

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Because you dont leave it in the flame long enough for your skin to heat up enough. ukmicky, Sun, 7th Sep 2008

Doesn't work with a blow torch ! neilep, Mon, 8th Sep 2008

...erhmm...unless it's not lit !! neilep, Mon, 8th Sep 2008

well, I think maybe when you pass your finger though the fame you are also pushing air at the  flame which possibly forces the flame away from te skin Long enough to pass the finger over it...
i think maybe if one just loweed the finger over the flame then you would recieve a burn as their is nowhere fir the flame to lean as it is on the entire wick.. does tht make any sense.... could that be why? Karen W., Mon, 8th Sep 2008

I used to this all the time...Michael is absolutely right...it's just not within the flame long enough...though...you do accumulate soot which looks impressive ! neilep, Mon, 8th Sep 2008

that amazes me..I am to afraid to burn my finger to try it.....I am sceered of fire!! Lol..... It even leaves soot??  We should dub you boys, Sir sparkies.... masters of the flames!!! Karen W., Mon, 8th Sep 2008

Of course..as a sheepy I have to be extremely careful....wool burns !! neilep, Mon, 8th Sep 2008


Does if you move it quick enough but, since I dont advocate swinging your hands about near very hot things, don't try this at home. Bored chemist, Mon, 8th Sep 2008

Yes Sheepy ...You be careful Please.. as there is not much worse then the smell of Dirty, stinky old burning wool!!!!! Yuckkkkkkkk!

Oh not to mention singed wool  could turn our Sheepy To the Darkside.... then where would we all be if we lost the power of The Sheepy!!!
Long live our hero Sheepy... May the force be with you....
and never allow the wool to be pulled over your eyes. as sheepy is Hot....but If you singed your beautiful wool It may make you a bit to well done  ........not only will you be Hot, but you will be smokin' Hot......!!!! You won't be able to stand  yourself!!! Hee Hee..... Karen W., Mon, 8th Sep 2008

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