Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 21/07/2012 07:30:02
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Jared Wainwright asked the Naked Scientists:
Hello Dr Chris, I was just wondering why we should be concerned if our
Microwave ovens leak microwaves (hopefully mine doesn't), yet it's OK
for mobile phones to?
One last point, am I correct in thinking, if I'm downloading something
via 3g (usually one of your podcasts), the majority of microwaves are
being received rather than my phone transmitting microwaves, apart
from the initial request and packet acknowledgements, or re-requests
of failed packets. I presume everyone near the transmitter/in my cell
will be exposed to similar limited microwaves?
The show is excellent! (http://www.thenakedscientists.com/HTML/podcasts/)
Many thanks
Jared (Stoke On Trent)
What do you think?
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Microwave ovens are very well shielded, so that the amount of leakage is only a few tens of milliwatts, and you stand back from it when it's in use.
A mobile phone generates roughly a watt or so of radio power, isn't shielded, and you usually place it directly by your head.
So overall a mobile phone is riskier... but having said that the evidence that even a mobile phone is (by any normal standards) risky isn't particularly strong.
It's probably best to consider things in terms of risk hierarchies; the chance of you dying of old age or disease or accident is 100%, the chances of dying from smoking (if you do that) is about 50%. The chances of being killed in a car crash might be 0.1% or something. Worse case chances of a mobile phone killing you isn't exactly known, but the evidence is that it is much much lower than being killed in a car crash... and microwave ovens are a lot safer still, so far as I know, nobody has ever died from the radiation from a microwave oven which was being used in any normal way.
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The biggest risk from a Microwave oven if you run it with the covers off is from the Magetron PSU which could certainly certainly give you serious shock if you tangled with it.
The chances dying in a traffic related accident in the UK are about 0.003% per year or in a 80 year lifetime 0.25%