Boing Boing's Bad Science Day
Feb. 4th, 2006 11:12 amOver on Boing Boing, Cory Doctorow quotes from from a 'HOWTO' page explaining how to boil an egg with two mobile phones. He does refer to this as a 'claim' but I can't help thinking that a little critical reflection might not have gone amiss before repeating this story.
Let's do the elementary science on this.
An medium egg weighs about 50g, and we'll assume that it is mostly water and thus has a specific heat of about 4200 J/kg/K. In other words, it takes 4200 joules of energy to heat up a kg of egg by 1 kelvin (i.e. 1 degree C).
If we start with our egg at room temperature - say 20 deg C - then to boil it we have to increase its temperature by 80 deg C. The energy required to do this for a 50g (0.05kg) egg is:
E(boil) = 80 x 0.05 x 4200 = 16,800 J
This is how much energy we have to get into the egg to raise its temperature to boiling point. Now, one watt of power is one joule per second. So to do this in three minutes (180s) takes a power transfer of 16800/180 = 93W.
In other words, if you can get about 100W into a medium size egg, you will heat it up to boiling point in about three minutes. Except that:
- This assumes complete energy transfer into the egg. For heating it with microwave energy, this assumes that all the energy from the transmitter is going into the egg and that it is all absorbed. A microwave oven tries to achieve this by putting the food to be cooked in a reflective cavity where the only place microwaves can go is into the food. But even if you put an egg right next to an antenna in the open, only part of the energy will go into it - a lot will go the other way, or even through the egg without being absorbed.
- This also assumes that the egg loses no heat as it warms up. This is unrealistic, as it will be radiating away heat (faster as it gets hotter) and being cooled by air convection.
In summary, the idea that 4W worth of mobile phone power could boil an egg in three minutes is complete bollocks. But then a quick look around the web site in question might have suggested that it's not entirely serious.
Even without the detailed physics argument though, a moment's thought should have shown how unlikely this is. An egg is mostly water. Your ear is mostly water. If a mobile phone next to an egg could boil it in three minutes, what would it do to your ear during a typical phone call? (And this is presumably why the article calls for two mobiles, so that you suspect some sort of weird interference effect. This can happen, but it just localises the heating, not enhances it.)
Why do I care enough to even post about this? Because the general lack of science literacy frustrates me, and because the lack of critical thought or fact-checking on Boing Boing is - especially because the site is in other respects so engaging - really quite depressing.
Let's do the elementary science on this.
An medium egg weighs about 50g, and we'll assume that it is mostly water and thus has a specific heat of about 4200 J/kg/K. In other words, it takes 4200 joules of energy to heat up a kg of egg by 1 kelvin (i.e. 1 degree C).
If we start with our egg at room temperature - say 20 deg C - then to boil it we have to increase its temperature by 80 deg C. The energy required to do this for a 50g (0.05kg) egg is:
E(boil) = 80 x 0.05 x 4200 = 16,800 J
This is how much energy we have to get into the egg to raise its temperature to boiling point. Now, one watt of power is one joule per second. So to do this in three minutes (180s) takes a power transfer of 16800/180 = 93W.
In other words, if you can get about 100W into a medium size egg, you will heat it up to boiling point in about three minutes. Except that:
- This assumes complete energy transfer into the egg. For heating it with microwave energy, this assumes that all the energy from the transmitter is going into the egg and that it is all absorbed. A microwave oven tries to achieve this by putting the food to be cooked in a reflective cavity where the only place microwaves can go is into the food. But even if you put an egg right next to an antenna in the open, only part of the energy will go into it - a lot will go the other way, or even through the egg without being absorbed.
- This also assumes that the egg loses no heat as it warms up. This is unrealistic, as it will be radiating away heat (faster as it gets hotter) and being cooled by air convection.
In summary, the idea that 4W worth of mobile phone power could boil an egg in three minutes is complete bollocks. But then a quick look around the web site in question might have suggested that it's not entirely serious.
Even without the detailed physics argument though, a moment's thought should have shown how unlikely this is. An egg is mostly water. Your ear is mostly water. If a mobile phone next to an egg could boil it in three minutes, what would it do to your ear during a typical phone call? (And this is presumably why the article calls for two mobiles, so that you suspect some sort of weird interference effect. This can happen, but it just localises the heating, not enhances it.)
Why do I care enough to even post about this? Because the general lack of science literacy frustrates me, and because the lack of critical thought or fact-checking on Boing Boing is - especially because the site is in other respects so engaging - really quite depressing.
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Date: 2006-02-04 01:25 pm (UTC)no subject
Date: 2006-02-04 01:48 pm (UTC)no subject
Date: 2006-02-04 02:20 pm (UTC)- I have been feeling more and more uncomfortable about what I see as 'WikiJournalism' - an apparent assumption that you don't need to validate sources or check facts on blogs, because your readers will do it for you. For a personal blog this may be fine, but I'm not sure how well this view scales to such a widely-read and respected site as Boing Boing.
- In light of this, I was a bit taken aback by Cory's accusation against Andrew Orlowski of a '"ready, fire, aim" approach to critical journalism' in this post, which I'd only just come across via this later one.
I've got a lot of time for Cory, and he's an acknowledged and valuable expert in the digital rights arena. But God, I wish he'd learn to check his facts. You can only fly so far on reputation alone, and I'd hate to see his being abraded away.
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Date: 2006-02-04 02:35 pm (UTC)I really wouldn't worry about people being deluded by the bad science in such puff stories as this. There are much bigger whoppers being told out there.
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Date: 2006-02-04 02:46 pm (UTC)The problem with ill-informed news is that it sounds more interesting than genuine stuff. Look at the whole area of urban myths. People used to worry that the public believed them as gospel, but the labelling of the genre shows that the public know they are just tall tales, not practical recipes. Look at the Mythbusters programme. Some of what they do is scientific rebuttal of ideas that anyone could do if they just got off their arses, like the magic powers of vodka and coke, but the big drawer is staging the big dangerous stunts that just sound fun. There is some element of public education. in the former, but I suspect the audience really tune in for the big bangs
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Date: 2006-02-04 02:59 pm (UTC)I have a hot button about people who rag on me extra-hard for errors of fact, grammar, or temperament in online conversations, informing me that because of my big-deal position as a major SF book editor I have some obligation to live up to a higher standard of casual conversation which they've dreamed up for me. My news for those people is "piss off." I don't claim to be any more of a paragon than the next fan, and I don't see why the price of accomplishing whatever I've accomplished in my day job should be that I'm no longer allowed to hang out and shoot the breeze like everyone else. So perhaps you can see why I take a somewhat dim view of your attempt to impose a level of advance fact-checking onto Cory's blog which nobody imposes on other personal blogs. It is an important principle of civilization that we are not responsible for what we do in other people's dreams.
And you know, Cory did in fact refer to the egg-boiling thing only as a "claim." You hand-waved this fact away as if it makes no difference, but it makes all the difference.
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Date: 2006-02-04 03:18 pm (UTC)You might be able to do something with a seriously broken WCDMA phone, however, the energy calculation remains the same and you'll lose the battery before you do anything serious.
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Date: 2006-02-04 03:23 pm (UTC)Interestingly, the answer was yes - you are safe, under very little water, even from very very very big guns. (The smaller guns were actually more dangerous).
They were as surprised as I was.
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Date: 2006-02-04 03:37 pm (UTC)no subject
Date: 2006-02-04 03:40 pm (UTC)no subject
Date: 2006-02-04 03:48 pm (UTC)Now my instinct as a communitarian is to feel that once any enterprise achieves a level of power, influence or popularity it is subject to some wider level of social accountability. But I can equally well see the enormous problems this can cause, and the sheer silliness that would ensue if any effort was made to put this into practice.
[As an example, I recall either watching or reading about a panel on sf publishing where an editor - and if it was you, my apologies for forgetting this - bemoaning the tendency of some unsuccessful writers to complain that his editorial policy should have a formal appeal process. "It does!" he replied - and named one of his main competitors.]
I'll concede that I've been rather harsh here. Boing Boing is as you say basically a personal website, and it's out of order for me to hold Cory to standards he hasn't himself set or sought to have imposed upon him. (I am worried, with my legal head on, that one day he'll say something online that will bring him closer than he might like to English libel laws, but then again that's his business, not mine.
Cory, if you read this, my apologies for misaimed crankiness. I'll go back to bed and try to get out on the right side, this time.
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Date: 2006-02-04 03:54 pm (UTC)However, there was one case where they debunked as a myth something I know to be true. They investigated a claim that you could 'hear' high-energy radio transmissions via your fillings, and decided that it probably wasn't feasible. Well, I can report from personal experience that if you inadvertently stand in the beam of an AR-3D air surveillance radar, even outside the nominal radiation hazard zone, it doesn't take long to realise that the 'zinggggg' you can half-feel, half-hear every ten seconds is perhaps related to the rotation rate of the radar dish!
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Date: 2006-02-04 04:09 pm (UTC)I remember that panel. IIRC, the editor in question was the other Nielsen Hayden!
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Date: 2006-02-04 05:41 pm (UTC)no subject
Date: 2006-02-04 07:04 pm (UTC)no subject
Date: 2006-02-04 07:23 pm (UTC)no subject
Date: 2006-02-04 07:42 pm (UTC)no subject
Date: 2006-02-04 10:11 pm (UTC)no subject
Date: 2006-02-04 11:02 pm (UTC)