Is fire a solid, a liquid, or a gas? - Elizabeth Cox

2,530,641 views

2018-11-05 ใƒป TED-Ed


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Is fire a solid, a liquid, or a gas? - Elizabeth Cox

2,530,641 views ใƒป 2018-11-05

TED-Ed


์•„๋ž˜ ์˜๋ฌธ์ž๋ง‰์„ ๋”๋ธ”ํด๋ฆญํ•˜์‹œ๋ฉด ์˜์ƒ์ด ์žฌ์ƒ๋ฉ๋‹ˆ๋‹ค.

๋ฒˆ์—ญ: Hyeona Seo ๊ฒ€ํ† : Jihyeon J. Kim
00:07
Sitting around a campfire, you can feel its heat,
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๋ชจ๋‹ฅ๋ถˆ ์ฃผ์œ„์— ์•‰์•„์žˆ์œผ๋ฉด ์—ด๊ธฐ๋ฅผ ๋Š๋‚„ ์ˆ˜ ์žˆ๊ณ 
00:09
smell the woody smoke, and hear it crackle.
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๋‚˜๋ฌด ํƒ€๋Š” ๋ƒ„์ƒˆ๋ฅผ ๋งก์„ ์ˆ˜ ์žˆ์œผ๋ฉฐ ํƒํƒ ์†Œ๋ฆฌ๋ฅผ ๋“ค์„ ์ˆ˜ ์žˆ์ง€์š”.
00:13
If you get too close,
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๋ถˆ ๊ฐ€๊นŒ์ด๋กœ ๋„ˆ๋ฌด ๋งŽ์ด ๊ฐ€๋ฉด ๋ˆˆ์ด ๋œจ๊ฒ๊ณ , ์ฝ”๋Š” ๋”ฐ๊ฐ€์›Œ์ง‘๋‹ˆ๋‹ค.
00:14
it burns your eyes and stings your nostrils.
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00:17
You could stare at the bright flames forever
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ํœ˜๊ฐ๊ธฐ๋ฉฐ ํ”๋“ค๋ฆฌ๋Š” ๋์—†๋Š” ๋ฐ์€ ๋ถˆ๊ฝƒ์„ ์˜์›ํžˆ ๋ณผ ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค.
00:19
as they twist and flicker in endless incarnations.
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00:23
But what exactly are you looking at?
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์—ฌ๋Ÿฌ๋ถ„์ด ๋ณด๋Š” ๊ฒƒ์€ ์ •ํ™•ํžˆ ๋ฌด์—‡์ผ๊นŒ์š”?
00:25
The flames are obviously not solid,
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๋ถˆ๊ฝƒ์€ ๋ช…๋ฐฑํ•˜๊ฒŒ ๊ณ ์ฒด๊ฐ€ ์•„๋‹ˆ๊ณ 
00:28
nor are they liquid.
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์•ก์ฒด๋„ ์•„๋‹™๋‹ˆ๋‹ค.
00:29
Mingling with the air, theyโ€™re more like a gas,
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๊ณต๊ธฐ์™€ ์–ด์šธ๋ฆฌ๋Š” ๊ฒƒ์„ ๋ณด๋ฉด ๊ทธ๊ฒƒ์€ ๊ธฐ์ฒด๊ฐ™๊ธฐ๋„ ํ•œ๋ฐ
00:33
but more visible--and more fleeting.
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๋ถˆ์€ ๋ณผ ์ˆ˜ ์žˆ๊ณ  ์ˆœ๊ฐ„์ ์ž…๋‹ˆ๋‹ค.
00:35
And on a scientific level, fire differs from gas
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๊ณผํ•™์ ์œผ๋กœ ๋ณด๋ฉด ๋ถˆ์€ ๊ธฐ์ฒด์™€๋Š” ๋‹ค๋ฅธ๋ฐ
00:39
because gases can exist in the same state indefinitely
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๊ธฐ์ฒด๋Š” ๋™์ผํ•œ ์ƒํƒœ๋กœ ์˜์›ํžˆ ์กด์žฌํ•  ์ˆ˜ ์žˆ์ง€๋งŒ
00:43
while fires always burn out eventually.
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๋ถˆ์€ ๊ฒฐ๊ตญ์—๋Š” ๊บผ์ง€๊ธฐ ๋•Œ๋ฌธ์ž…๋‹ˆ๋‹ค.
00:47
One misconception is that fire is a plasma,
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๋ถˆ์— ๋Œ€ํ•œ ํ•œ๊ฐ€์ง€ ์˜คํ•ด๋Š” ๋ถˆ์ด ํ”Œ๋ผ์ฆˆ๋งˆ๋ผ๋Š” ๊ฑด๋ฐ
00:50
the fourth state of matter in which atoms
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ํ”Œ๋ผ์ฆˆ๋งˆ๋Š” ์ œ4์˜ ๋ฌผ์งˆ ์ƒํƒœ์ด๋ฉฐ
์›์ž๊ฐ€ ์ „์ž๋ฅผ ๋นผ์•—๊ธด ์ƒํƒœ์ž…๋‹ˆ๋‹ค.
00:53
are stripped of their electrons.
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00:55
Like fire and unlike the other kinds of matter,
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๋ถˆ๊ณผ ๊ฐ™์ง€๋งŒ ๋‹ค๋ฅธ ๋ฌผ์งˆ๊ณผ๋Š” ๋‹ฌ๋ฆฌ
00:58
plasmas donโ€™t exist in a stable state on earth.
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ํ”Œ๋ผ์ฆˆ๋งˆ๋Š” ์ง€๊ตฌ์—์„œ ์•ˆ์ •ํ•œ ์ƒํƒœ๋กœ ์กด์žฌํ•˜์ง€ ์•Š์Šต๋‹ˆ๋‹ค.
01:03
They only form when gas is exposed to an electric field or superheated
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ํ”Œ๋ผ์ฆˆ๋งˆ๋Š” ๊ธฐ์ฒด๊ฐ€ ์ „๊ธฐ์žฅ์— ๋…ธ์ถœ๋˜๊ฑฐ๋‚˜
์ˆ˜์ฒœ ๋˜๋Š” ์ˆ˜๋งŒ ๋„๋กœ ๊ณผ์—ด๋˜์—ˆ์„ ๋•Œ ํ˜•์„ฑ๋ฉ๋‹ˆ๋‹ค.
01:08
to temperatures of thousands or tens of thousands of degrees.
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01:13
By contrast, fuels like wood and paper burn
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๋Œ€์กฐ์ ์œผ๋กœ, ๋‚˜๋ฌด์™€ ์ข…์ด ๊ฐ™์€ ์—ฐ๋ฃŒ๋Š” ๋ช‡๋ฐฑ ๋„๋ฉด ํƒ€์ง€์š”.
01:16
at a few hundred degrees โ€”far below the
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ํ”Œ๋ผ์ฆˆ๋งˆ์˜ ํ•œ๊ณ„์ ์— ๋น„ํ•ด ํ›จ์”ฌ ์•„๋ž˜์˜ ์˜จ๋„์—์„œ์š”.
01:19
threshold of what's usually considered a plasma.
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01:24
So if fire isnโ€™t a solid, liquid, gas,
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๊ทธ๋Ÿผ ๋ถˆ์ด ๊ณ ์ฒด, ์•ก์ฒด, ๊ธฐ์ฒด๋„ ์•„๋‹ˆ๊ณ 
01:27
or a plasma, what does that leave?
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ํ”Œ๋ผ์ฆˆ๋งˆ๋„ ์•„๋‹ˆ๋ผ๋ฉด, ๋„๋Œ€์ฒด ๋ฌด์—‡์ผ๊นŒ์š”?
01:30
It turns out fire isnโ€™t actually matter at all.
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์‚ฌ์‹ค ๋ถˆ์€ ๋ฌผ์งˆ์ด ์•„๋‹ˆ๋ผ๊ณ  ํ•ฉ๋‹ˆ๋‹ค.
01:33
Instead, itโ€™s our sensory experience of a chemical reaction called combustion.
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๋ถˆ์€ ์—ฐ์†Œ๋ผ๊ณ  ๋ถˆ๋ฆฌ๋Š” ํ™”ํ•™์  ๋ฐ˜์‘์— ๋Œ€ํ•œ ์šฐ๋ฆฌ์˜ ๊ฐ๊ฐ์ ์ธ ๊ฒฝํ—˜์ด์ง€์š”.
01:39
In a way, fire is like the leaves changing color in fall,
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์–ด๋–ค ๋ฉด์—์„œ ๋ถˆ์€ ๊ฐ€์„์— ๋‚˜๋ญ‡์žŽ ์ƒ‰์ด ๋ณ€ํ•˜๋Š” ๊ฒƒ๊ณผ ๊ฐ™๊ณ 
01:43
the smell of fruit as it ripens,
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๊ณผ์ผ์ด ์ต์–ด๊ฐ€๋Š” ๋ƒ„์ƒˆ์™€๋„ ๊ฐ™์œผ๋ฉฐ
01:46
or a fireflyโ€™s blinking light.
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๋˜๋Š” ๋ฐ˜๋”ง๋ถˆ์ด์˜ ๋ฐ˜์ง์ด๋Š” ๋น›๊ณผ๋„ ๊ฐ™์Šต๋‹ˆ๋‹ค.
01:48
All of these are sensory clues that a
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์ด๋Ÿฌํ•œ ๋ชจ๋“  ๊ฒƒ๋“ค์€
ํ™”ํ•™์  ๋ฐ˜์‘์ด ์ผ์–ด๋‚˜๋Š” ๊ฐ๊ฐ์  ๋‹จ์„œ์ž…๋‹ˆ๋‹ค.
01:51
chemical reaction is taking place.
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01:54
What differs about fire is that it engages a lot of
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๋ถˆ์˜ ํŠน์„ฑ์€ ์—ฌ๋Ÿฌ ๊ฐ๊ฐ์„ ๋™์‹œ์— ์ž๊ทนํ•œ๋‹ค๋Š” ๊ฒƒ์ด์ง€์š”.
01:57
our senses at the same time, creating the kind of vivid
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๋ฌผ๋ฆฌ์ ์ธ ๊ฒƒ์—์„œ ๊ธฐ๋Œ€ํ•˜๋Š” ์ƒ์ƒํ•œ ๊ฒฝํ—˜์„ ๋งŒ๋“ญ๋‹ˆ๋‹ค.
02:00
experience we expect to come from a physical thing.
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02:05
Combustion creates that sensory experience
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์—ฐ์†Œ๋Š” ๊ฐ๊ฐ์˜ ๊ฒฝํ—˜์„ ๋งŒ๋“ญ๋‹ˆ๋‹ค.
02:08
using fuel, heat, and oxygen.
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์—ฐ๋ฃŒ, ์—ด๊ณผ ์‚ฐ์†Œ๋ฅผ ์ด์šฉํ•ด์„œ์š”.
02:11
In a campfire, when the logs are heated to their ignition temperature,
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๋ชจ๋‹ฅ๋ถˆ ์•ˆ์—์„œ ํ†ต๋‚˜๋ฌด๊ฐ€ ๋ฐœํ™”์ ์— ๋„๋‹ฌ๋˜์—ˆ์„ ๋•Œ
02:15
the walls of their cells decompose,
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ํ†ต๋‚˜๋ฌด์˜ ์„ธํฌ๋ฒฝ์€ ๋ถ„ํ•ด๋˜๊ณ 
02:18
releasing sugars and other molecules into the air.
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๋‹น๊ณผ ๋‹ค๋ฅธ ๋ถ„์ž๋“ค์„ ๊ณต๊ธฐ๋กœ ๋ฐฉ์ถœ์‹œํ‚ต๋‹ˆ๋‹ค.
02:22
These molecules then react with airborne oxygen
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์ด ๋ถ„์ž๋“ค์€ ๊ณต์ค‘์˜ ์‚ฐ์†Œ์™€ ๋ฐ˜์‘ํ•˜๋ฉฐ
02:25
to create carbon dioxide and water.
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์ด์‚ฐํ™”ํƒ„์†Œ์™€ ๋ฌผ์„ ๋งŒ๋“ญ๋‹ˆ๋‹ค.
02:27
At the same time, any trapped water in the logs
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๋™์‹œ์— ํ†ต๋‚˜๋ฌด ์•ˆ์— ์žˆ๋˜ ๋ฌผ์€
02:31
vaporizes, expands, ruptures the wood around it,
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์ฆ๋ฐœํ•˜๊ณ , ํŒฝ์ฐฝํ•˜๊ณ , ์ฃผ์œ„์˜ ๋‚˜๋ฌด๋ฅผ ๋ถ€์ˆ˜๊ณ ๋Š”
02:35
and escapes with a satisfying crackle.
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๋ฉ‹์ง„ ํƒํƒ ์†Œ๋ฆฌ๋ฅผ ๋‚ด๋ฉฐ ๋น ์ ธ๋‚˜๊ฐ‘๋‹ˆ๋‹ค.
02:39
As the fire heats up, the carbon dioxide and water vapor
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๋ถˆ์˜ ์˜จ๋„๊ฐ€ ๋†’์•„์งˆ์ˆ˜๋ก ์ด์‚ฐํ™”ํƒ„์†Œ์™€ ์ˆ˜์ฆ๊ธฐ๋Š”
02:43
created by combustion expand.
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์ปค์ง„ ์—ฐ์†Œ๋กœ ์ธํ•ด ๋” ๋งŽ์ด ๋งŒ๋“ค์–ด์ง‘๋‹ˆ๋‹ค.
02:45
Now that theyโ€™re less dense, they rise in a thinning column.
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๊ทธ๊ฒƒ์€ ์œ„๋กœ ์˜ฌ๋ผ๊ฐˆ์ˆ˜๋ก ๋ฐ€๋„๋Š” ๋‚ฎ์•„์ง€๊ณ  ์–‡์€ ๊ธฐ๋‘ฅ์œผ๋กœ ์ƒ์Šนํ•ฉ๋‹ˆ๋‹ค.
02:50
Gravity causes this expansion and rising, which gives
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์ค‘๋ ฅ์€ ์ด๋Ÿฌํ•œ ํ™•์žฅ๊ณผ ๋ถˆ๊ธธ์„ ๋งŒ๋“œ๋Š”๋ฐ
02:53
flames their characteristic taper.
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๋ถˆ๊ฝƒ์˜ ์ ์  ๊ฐ€๋Š˜์–ด์ง€๋Š” ํŠน์„ฑ์„ ๋งŒ๋“ค์ง€์š”.
02:56
Without gravity, molecules donโ€™t separate
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์ค‘๋ ฅ์ด ์—†์œผ๋ฉด ๋ถ„์ž๋Š” ๋ฐ€๋„์— ๋”ฐ๋ผ ๋ถ„๋ฆฌ๋˜์ง€ ์•Š์œผ๋ฉฐ
02:59
by density and the flames have a totally different shape.
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๋ถˆ๊ฝƒ์€ ์ „ํ˜€ ๋‹ค๋ฅธ ๋ชจ์–‘์„ ๋ ๊ฒŒ ๋ฉ๋‹ˆ๋‹ค.
03:04
We can see all of this because combustion
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์šฐ๋ฆฌ๋Š” ์ด ๋ชจ๋“  ๊ฒƒ์„ ๋ณผ ์ˆ˜ ์žˆ๋Š”๋ฐ
์—ฐ์†Œ๋Š” ๋น›๋„ ๋ฐœ์ƒ์‹œํ‚ค๊ธฐ ๋•Œ๋ฌธ์ž…๋‹ˆ๋‹ค.
03:06
also generates light.
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03:08
Molecules emit light when heated,
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๋ถ„์ž๋Š” ๊ฐ€์—ด๋˜๋ฉด ๋น›์„ ๋ฐฉ์ถœํ•˜๊ณ 
03:11
and the color of the light depends
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๋น›์˜ ์ƒ‰์€ ๋ถ„์ž์˜ ์˜จ๋„์— ๋”ฐ๋ผ ๊ฒฐ์ •๋˜์ง€์š”.
03:12
on the temperature of the molecules.
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03:14
The hottest flames are white or blue.
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๊ฐ€์žฅ ๋œจ๊ฑฐ์šด ๋ถˆ๊ฝƒ์€ ํ•˜์–—๊ฑฐ๋‚˜ ํŒŒ๋ž—์Šต๋‹ˆ๋‹ค.
03:18
The type of molecules in a fire can
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๋ถˆ ์† ๋ถ„์ž์˜ ์ข…๋ฅ˜ ๋˜ํ•œ ๋ถˆ๊ฝƒ ์ƒ‰์— ์˜ํ–ฅ์„ ๋ฏธ์นฉ๋‹ˆ๋‹ค.
03:20
also influence flame color.
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03:22
For instance, any unreacted carbon atoms from the logs
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์˜ˆ๋ฅผ ๋“ค์–ด, ํ†ต๋‚˜๋ฌด ์†์˜ ๋ฐ˜์‘ํ•˜์ง€ ์•Š์€ ํƒ„์†Œ ๋ถ„์ž๋Š”
03:26
form little clumps of soot that rise
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์กฐ๊ทธ๋งˆํ•œ ๊ฒ€๋Œ•์˜ ๋ฌด๋ฆฌ๋ฅผ ๋งŒ๋“œ๋Š”๋ฐ
๊ฒ€๋Œ•๋“ค์€ ๋ถˆ๊ฝƒ ์‚ฌ์ด๋กœ ๋‚ ์•„๊ฐ€๋ฉฐ ๋ฐ์€ ์ฃผํ™ฉ์ƒ‰์˜ ๋น›์„ ๋ฐฉ์ถœํ•ฉ๋‹ˆ๋‹ค
03:29
into the flames and emit the yellow-orange
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03:32
light we associate with a campfire.
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๋ชจ๋‹ฅ๋ถˆ์„ ๋ณผ ๋•Œ ๋‚˜๋Š” ๋น›์ด์ฃ .
03:35
Substances like copper, calcium chloride,
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๊ตฌ๋ฆฌ, ์—ผํ™” ์นผ์Š˜, ์—ผํ™” ์นผ๋ฅจ ๊ฐ™์€ ๋ฌผ์งˆ๋“ค์€
03:38
and potassium chloride can add their
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๊ทธ ํŠน์ง•์ ์ธ ์ƒ‰๊น”์„ ๋”ํ•˜์—ฌ ์„ž์„ ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค.
03:40
own characteristic hues to the mix.
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03:43
Besides colorful flames,
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๋‹ค์ฑ„๋กœ์šด ๋ถˆ๊ฝƒ์€ ๋‘๊ณ 
03:45
fire also continues to generate heat as it burns.
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๋ถˆ์€ ๋˜ํ•œ ํƒ€๋ฉด์„œ ๊ณ„์†ํ•˜์—ฌ ์—ด์„ ๋ƒ…๋‹ˆ๋‹ค.
03:49
This heat sustains the flames by keeping
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์—ด์€ ๋ถˆ๊ฝƒ์ด ๊ณ„์†๋˜๊ฒŒ ํ•˜์ง€์š”.
์—ฐ๋ฃŒ๋ฅผ ๋ฐœํ™”์ ์ด๋‚˜ ๋ฐœํ™”์  ์ด์ƒ์œผ๋กœ ์œ ์ง€ํ•จ์œผ๋กœ์จ์š”.
03:52
the fuel at or above ignition temperature.
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03:55
Eventually, though, even the hottest fires
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๊ทธ๋ ‡์ง€๋งŒ ๊ฐ€์žฅ ๋œจ๊ฑฐ์šด ๋ถˆ๋„
03:58
run out of fuel or oxygen.
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๊ฒฐ๊ตญ ์—ฐ๋ฃŒ๋‚˜ ์‚ฐ์†Œ๊ฐ€ ๋ฐ”๋‹ฅ๋‚˜๋ฉด ๊บผ์ง‘๋‹ˆ๋‹ค.
04:01
Then, those twisting flames give a final hiss
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๊ทธ๋Ÿฌ๊ณ  ๋‚˜๋ฉด ์ถค์ถ”๋˜ ๋ถˆ๊ฝƒ๋„ ๋งˆ์ง€๋ง‰ ์‰ฌ์ต ์†Œ๋ฆฌ๋ฅผ ๋‚ด๊ณ ๋Š”
04:04
and disappear with a wisp of smoke
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ํ•œ ์ค„๊ธฐ ์—ฐ๊ธฐ์™€ ํ•จ๊ป˜ ์‚ฌ๋ผ์ง‘๋‹ˆ๋‹ค.
04:06
as if they were never there at all.
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๋งˆ์น˜ ๊ทธ๊ณณ์— ์—†์—ˆ๋˜ ๊ฒƒ์ฒ˜๋Ÿผ์š”.
์ด ์›น์‚ฌ์ดํŠธ ์ •๋ณด

์ด ์‚ฌ์ดํŠธ๋Š” ์˜์–ด ํ•™์Šต์— ์œ ์šฉํ•œ YouTube ๋™์˜์ƒ์„ ์†Œ๊ฐœํ•ฉ๋‹ˆ๋‹ค. ์ „ ์„ธ๊ณ„ ์ตœ๊ณ ์˜ ์„ ์ƒ๋‹˜๋“ค์ด ๊ฐ€๋ฅด์น˜๋Š” ์˜์–ด ์ˆ˜์—…์„ ๋ณด๊ฒŒ ๋  ๊ฒƒ์ž…๋‹ˆ๋‹ค. ๊ฐ ๋™์˜์ƒ ํŽ˜์ด์ง€์— ํ‘œ์‹œ๋˜๋Š” ์˜์–ด ์ž๋ง‰์„ ๋”๋ธ” ํด๋ฆญํ•˜๋ฉด ๊ทธ๊ณณ์—์„œ ๋™์˜์ƒ์ด ์žฌ์ƒ๋ฉ๋‹ˆ๋‹ค. ๋น„๋””์˜ค ์žฌ์ƒ์— ๋งž์ถฐ ์ž๋ง‰์ด ์Šคํฌ๋กค๋ฉ๋‹ˆ๋‹ค. ์˜๊ฒฌ์ด๋‚˜ ์š”์ฒญ์ด ์žˆ๋Š” ๊ฒฝ์šฐ ์ด ๋ฌธ์˜ ์–‘์‹์„ ์‚ฌ์šฉํ•˜์—ฌ ๋ฌธ์˜ํ•˜์‹ญ์‹œ์˜ค.

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