# The Naked Scientists Forum

### Author Topic: How many lightbulbs to fry an egg?  (Read 2354 times)

#### Super Hans

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##### How many lightbulbs to fry an egg?
« on: 26/01/2014 02:44:27 »
How many CFL light bulbs of average wattage would it take to fry an egg?

#### syhprum

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##### Re: How many lightbulbs to fry an egg?
« Reply #1 on: 26/01/2014 08:42:59 »
For some strange reason I cannot enter this reply as text so I sent it as a PNG!
Even when I try to add it as a modification!

We have to set up a lot of parameters before we can do any calculations let us assume the egg is sitting in a pan of approximately black body characteristics insulated from its surroundings one meter from the source of radiation and we wish to heat the pan to 127 degrees centigrade I would think if the colour temp of the radiation was similar to Sunlight we would need about 2KW/m^2 but without knowing the radiation spectrum of CFL lamps (which is not ideal for this purpose) I can proceed no further.

It seems it does not like this short section of text "400 (alt 248) K
« Last Edit: 26/01/2014 09:03:12 by syhprum »

#### RD

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##### Re: How many lightbulbs to fry an egg?
« Reply #2 on: 26/01/2014 08:56:32 »
The Easy-Bake-Oven used a 100W incandescent lightbulb.
« Last Edit: 26/01/2014 09:01:11 by RD »

#### CliffordK

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##### Re: How many lightbulbs to fry an egg?
« Reply #3 on: 26/01/2014 09:03:12 »
An Easy-Bake oven is a pretty simple device based on a 100W incandescent bulb.  The incandescent bulb cooks primarily with radiative heating.

I usually buy 5 to 15W CFL bulbs.  They do get a little bit warm, but I'm not sure you can get enough close enough to put out enough heat without very good insulation.

On the other hand, if you had a 40W bulb, then perhaps 3 of them might put out an equivalent heat to the 100W incandescent.

I'm seeing CFL's up to about 200W, which should put out enough heat to cook your egg with one bulb.
« Last Edit: 26/01/2014 09:05:35 by CliffordK »

#### Bored chemist

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##### Re: How many lightbulbs to fry an egg?
« Reply #4 on: 26/01/2014 15:29:59 »
If you put a 1 watt bulb in a well enough insulated bo, it will get hot enough to cook an egg. How long you have to wait is another matter.

Incidentally, if they cooked by radiant heating I suspect the surface would be charcoal before the rest of the food was cooked. I'm pretty sure that convection and conduction figure quite heavily too.

#### syhprum

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##### Re: How many lightbulbs to fry an egg?
« Reply #5 on: 26/01/2014 22:46:48 »
I assumed that the radiation would heat a pan that is why I specified a well insulated one made of good conductivity materiel with near black body characteristics once the egg got partly cooked it would turn white and reflect the radiant heat.
Maybe the pan should be allowed to heat up before the egg is dropped into it

PS has anyone else had trouble using ALT248 as degree

« Last Edit: 26/01/2014 22:56:10 by syhprum »

#### CliffordK

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##### Re: How many lightbulbs to fry an egg?
« Reply #6 on: 27/01/2014 01:44:45 »
PS has anyone else had trouble using ALT248 as degree
There seems to be issues with all of the extended ASCII characters.

Most of the Greek letters are coming in through unicode, but the degree symbol, some of the fractions like 1/2, 3/4, etc, the angstrom symbol, and most of the accents and umlauts are all extended ASCII and broken.  I think the British Pound symbol ₤ (the one with one hash doesn't work) may also be extended ASCII.  Fortunately the American Dollar \$ symbol works just fine  .

I've reported the error up the chain of command.  Hopefully they will check it out on Monday.

Oh, here's an idea.  What about using a lower case "o" as a superscript.

It is 32o outside

BTW: Kelvin is normally written without a degree symbol.
« Last Edit: 27/01/2014 07:01:15 by CliffordK »

#### syhprum

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##### Re: How many lightbulbs to fry an egg?
« Reply #7 on: 27/01/2014 21:26:42 »
Next time I fry eggs I will fix the pan 10 cm above the hot plate with a fan blowing away the hot air stream so that the pan is only heated by radiation.
Then after measuring the temperate of the hot plate and assuming that it is an isotropic black body radiator and that the pan is a black body absorber I will need only the radiation spectrum of the CFL lamps to calculate the nominal wattage of them that I will require to produce a similar result

#### syhprum

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##### Re: How many lightbulbs to fry an egg?
« Reply #8 on: 28/01/2014 06:26:22 »
Clifford K
I am surprised by your outside temperature seems more Melbourne than Oregon

#### CliffordK

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##### Re: How many lightbulbs to fry an egg?
« Reply #9 on: 28/01/2014 07:28:43 »
What will you say when it hits 95o next summer?  Or heaven forbid, breaks 100o?

Remember the USA is about the only country in the world that hasn't adopted the Metric system.

#### Bored chemist

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##### Re: How many lightbulbs to fry an egg?
« Reply #10 on: 28/01/2014 19:29:50 »
What will you say when it hits 95o next summer?  Or heaven forbid, breaks 100o?

Remember the USA is about the only country in the world that hasn't adopted the Metric system.

Yes they have adopted it: they just haven't noticed yet.
"In 1866, Congress authorized the use of the metric system and supplied each state with a set of standard metric weights and measures. "

"Under the Mendenhall Order in 1893, metric standards, developed through international cooperation under the auspices of BIPM, were adopted as the fundamental standards for length and mass in the United States."

from
http://en.wikipedia.org/wiki/Metrication_in_the_United_States

#### The Naked Scientists Forum

##### Re: How many lightbulbs to fry an egg?
« Reply #10 on: 28/01/2014 19:29:50 »