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HOWTO, Cook an Egg With Your Cell Phone 337

Posted by Hemos
from the the-joy-of-technology dept.
xPosiMattx writes "Suzzanna Decantworthy published an article in her Wymsey Weekend column that described how to cook an egg with two cell phones. From the article: "Many students, and other young people, have little in the way of cooking skills but can usually get their hands on a couple of mobile phones. So, this week, we show you how to use two mobile phones to cook an egg which will make a change from phoning out for a pizza.""
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HOWTO, Cook an Egg With Your Cell Phone

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  • Dupe (Score:3, Informative)

    by technoextreme (885694) on Monday February 06, 2006 @07:59PM (#14655644)
    Sigh.... Anyone actually like to find the article. I found this which shows it's a year old. PS. Woot. My first dupe whine. http://www.engadget.com/2005/09/07/boil-an-egg-ins tead-of-your-brain-with-your-cellphones/ [engadget.com]
  • by Toveling (834894) on Monday February 06, 2006 @08:00PM (#14655647)
    To create loud noise for the phones to pick up and transmit. Or you could yell into them...
  • by NitroWolf (72977) on Monday February 06, 2006 @08:02PM (#14655664)
    I feel foolish for asking but...
    What's the radio for??


    To generate traffic. On modern digital cell phones, if the line is silent, they don't transmit or recieve, or at least not enough to speak of. Saves on power.

    The radio will generate traffic and cause the power output of the phone to max out.
  • Brainiac (Score:5, Informative)

    by interiot (50685) on Monday February 06, 2006 @08:04PM (#14655680) Homepage
    Bzzt. Brainiac (an alternative to Mythbusters) tried this with 100 phones, and the phones were literally covering the egg, and they left the egg under there for a while. It definitely didn't cook, and they reported it didn't even get remotely warm either.
  • by six (1673) * on Monday February 06, 2006 @08:07PM (#14655709) Homepage
    I love urban legend as much as the next guy, but this isn't exactly true. These are cell phones not two-way radios. Phone A will be talking to a cell phone tower, whilst phone B is talking to a cell phone tower, whilst each cell phone tower is talking to the two phones respectively.

    Right the phones never connect directly on a GSM network, but either way their antennas are omnidirectional, so a phone talking to a tower on the opposite direction would still irradiate the egg with the same amount of energy ...

    A funny thing I noted is the "if you're giving a strong (audio) input the phone will emit with more power" ... come on, this would be true with pure analog phones, but GSM is not and that make this claim plain wrong

    Anyway, I don't see what this is doing on /.
  • A few problems (Score:5, Informative)

    by jmorris42 (1458) * <jmorris@[ ]u.org ['bea' in gap]> on Monday February 06, 2006 @08:08PM (#14655727)
    Problem #1. Handheld cellphones do not emit 2W. The old analog handhelds were capped at 700mW and I suspect the digitals emit much less based on the power available to them and the talktime.

    Problem #2. Even if you scrounged up some old bagphones with their 3W output power, they still only gives you six watts of power. I don't think that is going to cook an egg in the time claimed.
  • by Valdrax (32670) on Monday February 06, 2006 @08:09PM (#14655729)
    I love urban legend as much as the next guy, but this isn't exactly true. These are cell phones not two-way radios. Phone A will be talking to a cell phone tower, whilst phone B is talking to a cell phone tower, whilst each cell phone tower is talking to the two phones respectively. There is no reason to think that you are forming some sort of ultra powerful death beam between the two phones by placing them in close proximity to one another.

    Not so fast, yourself!

    This might be an urban legend, but I sure hope that you don't think that cell phones talk to their towers with some sort of directional beam. Cell phones and cell towers radiate their energy in all directions with roughly the same power and would point just as much energy towards the egg as towards the tower (or any other direction).

    The point of having two phones is so that you have control over the conversation and can run it at an arbitrary length without the other end hanging up. It also doubles the amount of power being broadcast at close proximity. The radio is there to keep the phone broadcasting.

    I'd try this myself when I get home tonight, but I only have the one phone.
  • This will never work (Score:5, Informative)

    by Sycraft-fu (314770) on Monday February 06, 2006 @08:13PM (#14655758)
    For so many reasons:

    1) Cell phones are the wrong frequency. They are 800, 900, 1800, or 1900 MHz depending on the service. To make water heat up, you need to be at the frequency water resonates which is 2.4GHz.

    2) Cell phones are too low power. A microwave that will cook an egg in a couple of minutes is going to have power expressed in at least the hundreds of watts, and probably will be 1000 watt. Cellphones have output power expressed in the miliwatts, that 1/1000th of a watt. We are literally talking over 5 orders of magnitude difference.

    3) Microwaves function because they build standing waves. You find that if you take the frequency of a microwave (printed on the back usually), measure the size of the cavity and run the numbers, it works out that it's of a size such that standing waves build up. Taking a magnetron out of the case makes it work very poorly, despite the power output.

    4) Cellphones operate in bursts. They do a burst when they have something to transmit, then fall silent. Saves on batteries. That's not going to cut it for heating, you need continous output.

    I'm not sure if this is a joke or what, but you'll never get something like this to work. To even have a chance, you'd need to use a cordless 2.4GHz phone. It's at least in the right frequency ballpark, never mind all the other problems.
  • a quick calculation (Score:3, Informative)

    by csimicah (592121) on Monday February 06, 2006 @08:14PM (#14655767)
    Assuming an egg has the heat capacity of 60g of water, and a 1000mAh * 3.7V cell phone battery, it looks like a fully charged cell phone battery could actually raise the temperature of an egg by 55 degrees C. That is, if you could somehow expend your entire battery into heat, and have it all go into the egg, you could cook one.

    The article is still a joke, of course - the egg won't even come close to warming by any measurable amount.
  • by McFadden (809368) on Monday February 06, 2006 @08:23PM (#14655826)
    I think you've perhaps missed the point. This isn't about producing a deathray - it's about having the extra radiating power of two phones to make the trick more effective. Calling one phone from another just makes it easier and cheaper than calling two separate third-parties (or should that be a third and fourth party!?)
  • It's a HOAX! (Score:5, Informative)

    by SiliconEntity (448450) on Monday February 06, 2006 @08:35PM (#14655905)
    This has been widely [flutterby.com] discussed [brainwagon.org] online [livejournal.com] and it is a pure hoax. The wymsey site also has such highly factual articles as hunting the wily tofu [wymsey.co.uk]. Obligatory dig at slashdot editors elided for space.
  • Holy bejesus (Score:3, Informative)

    by John Miles (108215) on Monday February 06, 2006 @08:36PM (#14655909) Homepage Journal
    How does anyone get out of high school without the ability to call bullshit on stuff like this?

    It takes one calorie to raise the temperature of one gram of water by one degree C. To a first approximation, an egg weighs about 50 grams, and is full of stuff whose specific heat is probably not too different from that of water. Let's say cooking an egg at room temperature requires you to raise its temperature by 50 degrees C for one minute. You will need something on the order of 2500 calories to do this, or about 10,000 joules. This energy will have to be transferred to the egg over a one-minute interval, assuming 100% efficiency.

    A joule is one watt-second, so this cooking process is going to require exposing the egg to about 166 watts for one minute. At 100% efficiency.

    A cell phone puts out about one watt, and good luck funnelling all of its output into an egg. (For extra credit, calculate the impedance of a chicken egg in free space, and design a suitable matching network).

    Now, if you'll excuse me, I need to get back to my public-safety campaign, warning gullible Americans about dangerous levels of radiation in voting booths.
  • by sjf (3790) on Monday February 06, 2006 @08:36PM (#14655911)
    A funny thing I noted is the "if you're giving a strong (audio) input the phone will emit with more power" ... come on, this would be true with pure analog phones, but GSM is not and that make this claim plain wrong

    Erm, not true. Analog phone are Frequency Modulated, power output is, for all intents and purposes, constant during transmit. The purpose of the radio is to ensure that both phones are transmitting continuously: a digital phone transmitting "silence" will have a much lower signal to noise ratio, and therefore less power output.

  • Snopes! (Score:3, Informative)

    by redelm (54142) on Monday February 06, 2006 @08:38PM (#14655920) Homepage
    First place [snopes.com] I check for these urban legends.

    If this were true, a naked magentron would be a great cellphone jammer. Even if not, it still might be!

  • by surial (941649) on Monday February 06, 2006 @08:40PM (#14655938)
    HOAX, people. On brainiac (british show. mythbusters but zanier) they tried this by burying an egg under 60+ phones and repeatedly dailing them all (which mythbusters has already proven generates the largest wattage spikes). Nothing happend to the egg.
  • by tttonyyy (726776) on Monday February 06, 2006 @08:42PM (#14655944) Homepage Journal
    The number of untrue or inaccurate statements in the posts about this article just go to show how little slashdot readers seem to actually think about the article (like that's a surprise).

    First off, as stated in an earlier port, 2.45GHz is NOT the resonant frequency of water molecules, otherwise only the surface of food in microwaves would be heated.

    http://rabi.phys.virginia.edu/HTW/microwave_ovens. html [virginia.edu]

    Cell phones work at 850MHz or 1850MHz, so it's not looking good right from the off.

    Second off, as stated by the article, "For instance, a pair of mobiles each with 2 Watts of transmitter output will take three minutes to boil a large free range egg."

    Four watts. Four joules per second.

    Lets look at this. I'll use some glaring assumptions just to get an estimate of the time taken to cook an egg with 4W (with is a factor of ten greater than you'd really expect from two mobile phone).

    First off, lets assume that you want to heat the egg (70g - it's a large egg) from 20C to 100C. I'm not sure if that constitutes cooking, but it'll do for now.

    Lets also assume that the energy required to heat the egg is similar to that of water (4186 J/kg).

    So energy required is 4186 * 0.07 * 80 = 23kJ.

    At 4W, we're talking 5860 seconds, or 98 minutes. And that's assuming 100% efficiency, which definitely won't be the case in this situation. (Not forgetting the already incorrect factor of ten for the phone output power, frequency of operation and burst nature of phone comms).

    By the by, I discovered this page on egg boiling science as I finished writing this post:

    http://newton.ex.ac.uk/teaching/CDHW/egg/ [ex.ac.uk]

    Perhaps someone with more patience than me can more accurately calculate the energy required to boil a 70g egg?

  • by Darth Liberus (874275) on Monday February 06, 2006 @08:49PM (#14655991)
    wouldn't the radiation have to be ionising for this to work? Nope. The phenomena that is (barely) at work here is dielectric heating [wikipedia.org], same principle as a microwave oven. Speaking of microwaves, the cell phone bands (900MHz and 1800Mhz) aren't particularly good at heating things up.
  • by modecx (130548) on Monday February 06, 2006 @08:51PM (#14656004)
    but wouldn't the radiation have to be ionising[sic] for this to work?

    All 'ionizing radiation means' is that the radiation is strong enough to break the strong bonds between atoms causing the subject of the radiation to become ionized. Basically if the energy of a photon is high enough (the higher the frequency, the higher the energy), an electron can be kicked out of whatever material it strikes, or so I understand.

    Normally, when a lower energy, non-ionizing photon strikes some object, it elevates the energy of the electrons in the atoms that compose the material, and during a brief moment the electrons jump away from the nucleus for a, and they fall back to their normal positions. In the process of doing this, heat is released into the object. Some of that heat energy will be radiated away as infrared radiation because when electrons fall back closer to the atom, photons are released, causing electromagnetic waves.

    The frequency your microwave uses is many orders of magnitude less energetic than the light impacting your eyeballs, and both are non-ionizing, excepting the UV you receive when you're outside.

    I think my explanation is pretty close to how it's thought to work, but anyone with more understanding of this subject is more than encouraged to correct me.
  • by shrtcircuit (936357) on Monday February 06, 2006 @08:52PM (#14656010)
    Technically while the phone itself is omnidirectional, a cell site is not. It isn't highly accurate, however the tower does know what direction you're calling from and will transmit to your phone in close to that direction using panel antennas. This is also one way that cell towers achieve greater call density, since there is no need to transmit away from the phone (what good would that do). This frees up channels on the antennas your call isn't being transmitted on to handle other users, and allows it to direct more power to you and not in directions that clearly don't need it.

    Of course the cell phone thing is ridiculous. Even IF you could get two modern (i.e. microwave-band) phones to operate at the full 2W continuously, you're a far cry from the hundreds of watts a microwave oven needs to cook the same eggs -- and a microwave oven has a resonation chamber to bounce the waves around until they're absorbed by the food. I suppose if you irradiated an egg using cell phones and could build a metal chamber to resonate those waves and contain them until absorption, you could eventually cook an egg. It would take a long time though, and for what it will cost you in either cell bills or fried phones you could have just bought a damn Egg McMuffin!
  • by Breakfast Pants (323698) on Monday February 06, 2006 @09:04PM (#14656074) Journal
    I know what you meant and I hate to be pedantic but cell phones are indeed two-way radios.
  • Since When (Score:2, Informative)

    by paulkoan (769542) on Monday February 06, 2006 @10:48PM (#14656686) Homepage Journal
    ... does phone A ever communicate with phone B?

    I know this has been debunked already, but anyways. Phone A talks to cell mast A and phone B talks to cell mast B.

    Cell mast A may or may not equal cell mast B.
  • by Limecron (206141) on Tuesday February 07, 2006 @12:17AM (#14657273)
    > A: you don't need to heat an egg to boiling to cook it.

    I will give you that the first part of A is probably true.

    However, the volume of an egg is at least half water, probably more like the human body around 80% or more. Remember it turns into a chicken which, like nearly all creatures on the Earth, are mobile sacks of water.

    > That brings the time down to 20 minutes - which is what the article says.

    FTA:
    "For instance, a pair of mobiles each with 2 Watts of transmitter output will take three minutes to boil a large free range egg"

    Where did you get 20 minutes from?

    It takes 3 minutes to hard boil an egg in water. There's no way your cell phone (or even a few of them) could put enough heat into an egg to make it's temperature go up even a couple degrees. You need to be able to put more heat into the object than the air around it can dissipate.
  • by Oestergaard (3005) on Tuesday February 07, 2006 @05:27AM (#14658413) Homepage
    Ok, first of all; if I could cook an egg in say five minutes using two phone, I could cook it in 10 minutes using one phone. I talk longer than that on the phone sometimes - how would the right side of my brain look if the phone actually emitted enough energy to boil an egg in that time? Right - you would faint after talking just a few seconds (heating the brain is *really* not a good-for-you thing to do). After 10 minutes of talking you wouldn't be able to guess your own name, should you wake up...

    So, obviously this is BS.

    Now. A big egg, let's say that's about 80 grams of mass, and that the specific heat of the combined egg contents is similar to water (shouldn't be too much of a long shot). So, we have 80 grams of something that has a specific heat close to 4 joules/(gram*kelvin).

    To boil that, we need to heat it about 80 kelvin (room temperature around 293 kelvin, water boiling at 373 kelvin). That's 4 [joules/(gram*kelvin)] * 80 [kelvin] = 320 [joules/gram].

    We had 80 grams of egg. This gives us 80 [grams] * 320 [joules/gram] = 25600 [joules].

    We had five minutes to do this - that's 5*60=300 seconds. A joule being one watt in one second, we get: 25600 [watt*second] / 300 [seconds] = 85 [watts]. So, using 85 watts for five minutes should get an egg from room temperature to the boiling point of water. Approximately.

    Each phone would then have to emit around 42 watts (could this be a coincidence? Oh, nevermind..).

    Let's say you get around one third of the energy into the egg (I'm really being generous here - the egg would have to cover 1/3 of the output of the antenna and completely absorb the energy) - you would need two phones each with a 126 watt transmitter.

    Mobile phones with 100+ watt transmitters? I know there are rural areas in the US of A, but I sincerely doubt that it's common to carry phones that pack that much punch.

    Besides, the article talked about 2 watt output phones... Again, BS.

    Ahhh.... Have a nice day.
  • by Anonymous Coward on Tuesday February 07, 2006 @05:32AM (#14658433)
    Two things: first, as another person already noted, this is a hoax.
    But second, the people who simply divide the applied wattage by the required energy to cook an egg in order to obtain a cooking duration miss the point that the egg radiates more energy as it heats. You need to use something like the Stefan-Boltzmann law (the T-to-the-fourth law) (consider the egg a blackbody):

    Power = (5.7*10^-12 W/cm^2/T^4)*(Area)*T^4

    A 15cm diameter egg (I measured one from the 'fridge) at equilibrium at room temperature is constantly absorbing and emitting about 3.3W. Increasing this by 2W gives a final temperature of about 66 C. The egg will never never get hotter than this.

    According to the indespensible "On Food and Cooking" by McGee, egg protien begins to coagulate at 63C, sets at 66C, and is really done at 71C. So depending on your definition of 'cooking' the egg, it's not that it will take a very long time, but that it will never happen, ever. Which is good, since as was pointed out, this is a hoax anyway.

    Cheers!

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