# Cell phone cooks egg

Discussion in 'General Discussion' started by linthat22, Jun 27, 2006.

1. ### linthat22 Regular

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okay, I shoulda put cell phones, cause they use 2 in the test. I don't like the sounds of this

Yike!!

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2. ### Zaphod Remember Veteran

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Fake/urban legend. Work out the physics of it. Even if *all* the energy expended by the phones (up to max 2W for old GSM phones, less than half for newer phones using the higher frequency bands) went into the eggs (which is obviously not the case) it would take several hours to boil an egg.

There was a television show that tested this with more than a hundred phones. Of course, to no apparent effect.

Edit: OK, so I'm bored and looked up the temperature for the yoke of an egg to coagulate, which is ~70 degrees Celsius. For a rough estimation, a calorie is ~4.18 Joule, and is the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius. We'll assume that eggs have similar properties, and that a normal breakfast egg is 65 grams. To give the cell phones a fighting chance we'll also assume that the egg has room temperature (20 degrees Celsius) before the experiment.

Thus we need: 50 x 65 x 4.18J ~ 13.600J. Since 1 Joule equals 1 Watt second, two modern cell phones, transmitting at max power, would need 1 hour 53 minutes to hard boil and egg, if there were no other energy loss (in reality, only a tiny fraction of the energy spent will actually work on the egg). If we're generous 10% of the transmitted energy will be absorbed bringing us to 18 hours 48 minutes. Then we have to factor in that quite a bit of heat will radiate from the egg into the cooler surrounding air... You get the point.

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Last edited by a moderator: Jun 27, 2006
3. ### Guden Oden Senior Member Legend

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The egg will likely dissipate any energy/heat it absorbs faster than it is received, under non-contrieved real-world conditions anyway. I'm sure someone could cook up some scenario in a lab (no pun intended) where this was not the case, perhaps using waveguides/reflectors or whatever, but that's cheating.

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4. ### ShootMyMonkey Veteran

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Another contrivance is simply that certain varieties of phones have heat issues with their batteries if you talk on them while they're plugged in. Two sources of energy, one of which is quite simply radiant heat can do something if you throw in all the other cheating.

People always seem to create stirs about things that are ubiquitous and in the end, it all fizzles on account of its own inherent stupidity. I'm sure some cell phone manufacturer will jump on this with a marketing campaign about low radiation energy emissions of their new model. It'll be like the whole "cholesterol-free vegetable oil" thing all over again.

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5. ### Zaphod Remember Veteran

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Probably not. The article from which this emanates is five years old. Apparently someone created some updated images around new-year, and that started making the rounds and the whole thing got posted almost everywhere. I remember seeing this on Slashdot a couple of months ago.

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6. ### Mize 3dfx Fan ModeratorLegendVeteran

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7. ### Fred Newcomer

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This is a good example of the sort of story that more or less decides if you passed 8th grade physics or failed it.

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8. ### KimB Legend

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Rather, the temperature of the egg will rise until the energy dissipated equals the energy input by the Cell phones (probably a couple of degrees C). If it dissipated more energy than it received, the egg would be cooling off

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9. ### LunchBox Regular

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wow
talk about cell phones that can do everything these days...
It also doubles as a crockpot

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10. ### linthat22 Regular

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You took physics in 8th grade? We just had regular "science class"

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