I spend a lot of time on Slashdot and today there was a story entitled HOWTO, Cook an Egg With Your Cell Phone. It linked to an article - hopefully a humorous one - claiming you can cook an egg with a cellular phone in two minutes. Those who use a cellular phone and haven't yet cooked their head after hours and hours of talking on it are surely wondering how this can be. The story linked to a page titled "Weekend Eating: Mobile Cooking".
Here's the part on "how to do it":
- Take an egg from the fridge and place it in the egg cup in the centre of the table.
- Switch on the radio or hifi and turn it up to a comfortable volume.
- Switch on phone A and place it on the table such that the antenna (the pokey thing at the top) is about half an inch from the egg (you may need to experiment to get the relative heights correct - paperbacks are good if you have any - if not you may be able to get some wood off cuts from your local hardware shop).
- Switch on phone B and ring phone A then place phone B on the table in a similar but complementary position to Phone A.
- Answer phone A - you should be able to do this without removing it from the table. If not, don't panic, just return the phone to where you originally placed on the table.
- Phone A will now be talking to Phone B whilst Phone B will be talking to Phone A.
- Cooking time: This very much depends on the power output of your mobile phone. For instance, a pair of mobiles each with 2 Watts of transmitter output will take three minutes to boil a large free range egg. Check your user manual and remember that cooking time will be proportional to the inverse square of the output power for a given distance from egg to phone.
- Cut out these instructions for future reference.
Below is a note I posted to Radio Wymsey's forums. Note that at least the people running the show don't seem to really believe that you can do this... It seems to be more a clever work of humor (or in this case humour, ha ha.)
What I want to know is, who actually believes the contents of the article? No handheld phone even puts out 2W. They tend to peak out closer to 3/4 watt - basically every pocket phone is under 1 watt. Only the old big handhelds and bag phones were over that, to the tune of about 1.5-2 or 3 watts respectively.
In addition we have an egg of about 50g. It begins refrigerated; Let's call that 3 degrees C. In order just to be safe, an egg must reach approximately 71C. We need to raise 50g of egg from 3 C to 71 C. One calorie of energy raises 1g of water by 1 degree C. One watt is about 0.25 calories per second.
Thus, we need four seconds from 1 watt before we even have 1 calorie expended. We have something more like 1.5 watts total with two handhelds. Three minutes gives us 180 seconds. That's 67.5 calories. The egg masses 50g. If ALL of that energy were put into the egg, and the egg radiated no energy, it would raise in temperature about 1.35 degrees C.
However, 100% of the energy doesn't go in the same direction. Cellular phone antennas are very low-gain; they are not directional, so that the phone will work in any orientation. In addition, the further away you get, the less energy is applied. Even putting the antenna INTO the egg would not ensure that all of the energy went into the egg, due to losses. Also, some of the energy will pass THROUGH the egg.
The main reason for THAT is that the frequency of water is higher than that of cellular phones. GSM phones are all under 2GHz. Water is closer to the 2.4GHz that 802.11b wireless ethernet and microwave ovens use. In fact, microwave ovens work specifically by vibrating water molecules; this movement causes friction, which causes heat, which cooks your food.
You would expend just as much energy making two totally separate phone calls. Cellular phones do not communicate in a point-to-point fashion. They talk to cells, not other phones. (This will change eventually, but it hasn't yet.) And of course, the further you are from the cell, the more power the phones use, so they can get a useful signal. The article doesn't even bring that up.
Finally, the ultimate(ly unnecessary) debunking: Braniac did this with like 100 phones already, and couldn't cook a single egg. Methinks there are a lot of suckers out there.