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FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?

 
Anonymous Coward
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08/31/2012 08:29 PM
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FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
The living-room is big enough that,
1 million candles fit with adequate ventilation.
Also, the flame temperature of 1 candle is about 1,000 °C

What temperature would my living room be with a million candles lit?

PEACE
Anonymous Coward
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08/31/2012 08:34 PM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
like teh surface of teh sun!!!
Anonymous Coward (OP)
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08/31/2012 08:36 PM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
like teh surface of teh sun!!!
 Quoting: Anonymous Coward 1023265

How do you figure?

Its a million candles.
Give me a temp-number.
nomuse (not logged in)
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09/04/2012 12:30 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
I just ran into this recently. Drat. My memory is no good these days.

Say a candle is about a watt and burns for 2 hours. Okay, I'll look it up! 80W. Wow; I was off by almost a magnitude.

Anyhoo, that means we are putting 80,000 kW out.

Typical sizing for a room heater is 10W/ square foot. Garage heater gets up to 5,000 W. This is quite a bit lower than our million candles!

But brings up the question; how big is the room? Model a candle as a rectangular solid 1" x 1" by 6" long or 6 CU. 6 million CU is 42,000 square feet. That's about the size of a Wallmart store, or a typical warehouse. Not including space for air circulation!

But let's assume that somehow, through some TARDIS-like trick of candle-ry, we've got them all crammed into a typical room of 150 square feet. And putting out the same power as a Eurorail locomotive hauling a train across the Swiss Alps! (Or, about 1/10 the typical output of a municipal power plant).

The rule of thumb for heating air at standard conditions is 0.0012 joules per cm^3 per degree Celsius. Or 32 joules to raise the temperature of one square foot by 1 degree.

We have 150 square feet of room air, but 80 megajoules every second being output by those million candles. All else being equal (which it very much is NOT) you'd raise the temperature of the air 16,000 degrees every second.

Fortunately heat only flows from hot to cool, so when equilibrium is reached between the air and room contents, and the candles, assuming the chemistry of a candle still works at an extremely high ambient temperature (NOT a good assumption), we could be at 1,400 C. (2,500 F, for those that don't speak Continental).

Which means, theoretically, within the burning time of those million candles the local temperature would be over the melting point of steel.



However, Randal Munroe style, I'm more intrigued by the ventilation problem.

A candle burns at .1 gm/minute. Assume that for this to happen, it has to combine with an equal mass of atmospheric oxygen, and as a candle will go out when the partial pressure drops to 8%, we need to supply roughly twice that volume as replacement.

Dry air has a density of about a kilogram per square meter. If I didn't just slip a decimal place, we need to move 16 kg or 16 square meters per second. Usual rating of fans is in CFM; we get 34,000 CFM when we convert.

Which is about the flow rate of this fan: [link to www.industrialfansdirect.com]

Those a five FOOT long fan blades, by the by. So you've got one of those things going full-out in the room with you and the candles.
Anonymous Coward (OP)
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09/04/2012 12:44 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
Wow dude you put in alot of work but how could you reach 1,400 C when the flame of a candle is 1,000 C
Anonymous Coward
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09/04/2012 12:48 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
The living-room is big enough that,
1 million candles fit with adequate ventilation.
Also, the flame temperature of 1 candle is about 1,000 °C

What temperature would my living room be with a million candles lit?

PEACE
 Quoting: Anonymous Coward 1353917


Where at in the living room? The room is going to be different temps at different areas.
Anonymous Coward
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09/04/2012 12:51 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
The candles would melt faster than the wicks can feed fuel and the temperature would bring up the wax to combustion temperature and then your house would be around 3000F for a few hours.


The rubble will still be hot so wait a few days before going back on your house. Notice I did not say in.
nomuse (not logged in)
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09/04/2012 12:52 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
Wow dude you put in alot of work but how could you reach 1,400 C when the flame of a candle is 1,000 C
 Quoting: Anonymous Coward 1353917


The average temperature of a candle flame is 1,000 C. The base is a little hotter.
Anonymous Coward
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09/04/2012 12:56 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
We need a ton more info than that.

Exact dimensions.

R value of the walls.

Temperature of the air outside.

Size and thickness of windows, double or single pane.

Chemical composition of the candles, burn rate.

That's just the start of the list.
Anonymous Coward
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09/04/2012 01:00 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
The living-room is big enough that,
1 million candles fit with adequate ventilation.
Also, the flame temperature of 1 candle is about 1,000 °C

What temperature would my living room be with a million candles lit?

PEACE
 Quoting: Anonymous Coward 1353917


Not referencing anything. I would say it ultimately depends on the square footage. Since no flame can directly increase the temperature of another, I would say the room would be 1,000 C.
Anonymous Coward (OP)
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09/04/2012 01:04 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
The living-room is big enough that,
1 million candles fit with adequate ventilation.
Also, the flame temperature of 1 candle is about 1,000 °C

What temperature would my living room be with a million candles lit?

PEACE
 Quoting: Anonymous Coward 1353917


Where at in the living room? The room is going to be different temps at different areas.
 Quoting: Anonymous Coward 22765077

Dude its just a quiz.

You don't win anything and most of you don't lose anything either by playing.

Just give an answer and small ex of why...
nomuse (not logged in)
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09/04/2012 01:10 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
Oh, and just for fun.

Assume that this is an ordinary living room -- 250 square feet (drat and drat...I let a square slip in above when I should have been in cubes. But anyhow!) Since we want to occupy the room, and we need space for the air to move (with that industrial-sized blower), let's arbitrarily say the candles occupy a mere 250 ft^2/2 /12' ceiling or 40.4 ft^3 -- which is close enough 1 one cubic meter, nicely enough.

The ordinary candle has a density of about 1 and weighs about 4 oz. With 1 million candles crammed into 1 cubic meter, however;

1 m^3 = a million cubic centimeters, so 4 oz/cc, or 113.4 gm/cm^3 ....just a little less dense than the core of the Sun.


So, yes...if these magic candles were still somehow ordinary wax, they'd stop wicking almost immediately and the wax itself would combust...but if they obey ordinary rules of density for matter the hydrogen in them would fuse and for a glorious nano-second you'd have a much hotter flame. Unfortunately, without robust containment that first moment of fusion would blow the super-wax blob apart.

I'd put the final yield no more than the low kiloton range. Be interesting to see if the first neutron release would be instantly fatal, however (I suspect, given the high percentage of fast neutrons in plain H-H fusion, that first particle flood would turn the contents of the room to plasma).
Anonymous Coward (OP)
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09/04/2012 01:13 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
The living-room is big enough that,
1 million candles fit with adequate ventilation.
Also, the flame temperature of 1 candle is about 1,000 °C

What temperature would my living room be with a million candles lit?

PEACE
 Quoting: Anonymous Coward 1353917


Not referencing anything. I would say it ultimately depends on the square footage. Since no flame can directly increase the temperature of another, I would say the room would be 1,000 C.
 Quoting: Anonymous Coward 16178844

That's my answer too.
Anonymous Coward (OP)
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09/04/2012 01:13 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
We need a ton more info than that.

Exact dimensions.

R value of the walls.

Temperature of the air outside.

Size and thickness of windows, double or single pane.

Chemical composition of the candles, burn rate.

That's just the start of the list.
 Quoting: Anonymous Coward 23087705

Ball park it bro.
Anonymous Coward
User ID: 22765077
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09/04/2012 01:14 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
We need a ton more info than that.

Exact dimensions.

R value of the walls.

Temperature of the air outside.

Size and thickness of windows, double or single pane.

Chemical composition of the candles, burn rate.

That's just the start of the list.
 Quoting: Anonymous Coward 23087705

Ball park it bro.
 Quoting: Anonymous Coward 1353917


Room temperature.
Anonymous Coward (OP)
User ID: 1353917
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09/04/2012 01:19 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
The candles would melt faster than the wicks can feed fuel and the temperature would bring up the wax to combustion temperature and then your house would be around 3000F for a few hours.


The rubble will still be hot so wait a few days before going back on your house. Notice I did not say in.
 Quoting: Anonymous Coward 11696035

See, I wouldn't come to this conclusion because the source of heat is the candle's flame 1,000 °C. Even if the source is added to a million more sources they could never produce more then their capacity being 1,000 °C. Unless something else catches on fire with a different combustion temperature.

PEACE
Anonymous Coward (OP)
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09/04/2012 01:25 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
Oh, and just for fun.

Assume that this is an ordinary living room -- 250 square feet (drat and drat...I let a square slip in above when I should have been in cubes. But anyhow!) Since we want to occupy the room, and we need space for the air to move (with that industrial-sized blower), let's arbitrarily say the candles occupy a mere 250 ft^2/2 /12' ceiling or 40.4 ft^3 -- which is close enough 1 one cubic meter, nicely enough.

The ordinary candle has a density of about 1 and weighs about 4 oz. With 1 million candles crammed into 1 cubic meter, however;

1 m^3 = a million cubic centimeters, so 4 oz/cc, or 113.4 gm/cm^3 ....just a little less dense than the core of the Sun.


So, yes...if these magic candles were still somehow ordinary wax, they'd stop wicking almost immediately and the wax itself would combust...but if they obey ordinary rules of density for matter the hydrogen in them would fuse and for a glorious nano-second you'd have a much hotter flame. Unfortunately, without robust containment that first moment of fusion would blow the super-wax blob apart.

I'd put the final yield no more than the low kiloton range. Be interesting to see if the first neutron release would be instantly fatal, however (I suspect, given the high percentage of fast neutrons in plain H-H fusion, that first particle flood would turn the contents of the room to plasma).
 Quoting: nomuse (not logged in) 2380183

Bottom line, even though the high temperatures of a million candles lit would melt the wax before the wicks top temperature couldn't be more then the source, the heat of its flame.

IMHO
Anonymous Coward
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09/04/2012 01:30 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
This is almost to dumb to reply to. If there is adequate ventilation for a million candles then I assume that means enough ventilation that they will remain candles and not melt. Therefore it couldn't get any hotter than wax melts or the ventilation would not have been adequate.

less than 60 c

that would be an insanely big living room
Anonymous Coward
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09/04/2012 01:32 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
Ummmm...like..do you Canadians EVER get outside?
nomuse (not logged in)
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09/04/2012 01:55 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
Yah. It's a badly modeled question. If it was phrased as "an arbitrary number of candles" you might get closer to the desired answer.
Anonymous Coward
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09/04/2012 02:31 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
When my Auntie lit 90 candles on Grandmother's cake in a smallish room it became full of smoke.The smoke rose to the ceiling and then pored down.

As they were little cake candles the first were nearly burnt down when the last was lit.

Great fun.....Do not try this at home.
Anonymous Coward (OP)
User ID: 1353917
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09/04/2012 11:58 AM
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Re: FRIDAY Night science quiz: How hot would my living-room get with a million candles lit?
This is almost to dumb to reply to. If there is adequate ventilation for a million candles then I assume that means enough ventilation that they will remain candles and not melt. Therefore it couldn't get any hotter than wax melts or the ventilation would not have been adequate.

less than 60 c

that would be an insanely big living room
 Quoting: DOUBLE-U-TEE-EFF??

Adequate ventilation means the candles are all lit.

The flame temperature of 1 candle is about 1,000 °C

What would be the temperature when all candles are lit?





GLP