I have bluetooth speaker that I can control (via bluetooth) with my phone. One day I happened to roll on top of my phone with my chest and the music stopped playing (until I rolled off of it and it started playing again).

If I am blocking the waves, is this dangerous?

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    $\begingroup$ What specific danger do you envision? $\endgroup$
    – WillO
    Sep 20, 2015 at 20:07
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    $\begingroup$ Yes, you absorb radio waves. You are mostly water. The absorption spectrum of water is easy to find with a google search. Whether this is dangerous is a medical or epidemiology question, not physics. $\endgroup$
    – The Photon
    Sep 20, 2015 at 20:26
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    $\begingroup$ Do radios, GPS units, or cell phones work where you live? If so, you are being bombarded by their radio waves every second of every day. Man-made radio signals have been going through and being absorbed by people's bodies everywhere on Earth since before your grandparents were born, and natural radio sources from space have been hitting every patch of ground on Earth for billions of years. And yet never has there been a single case of harm coming to someone because of this. $\endgroup$
    – user10851
    Sep 20, 2015 at 20:46

1 Answer 1


Microwave ovens work at a frequency of 2.45 GHz. Their principle of operation is that molecules of fat, or water, absorb this radiation, because they are polar molecules with an electric dipole moment and rotate in response to the stimulus of the electromagnetic field of the microwaves. This absorbed energy is then dispersed throughout the material through vibrations and collisions between molecules and atoms.

Apparently, bluetooth works at around frequencies of 2.4 GHz. You are made up mostly of fat and water! It is therefore a fact that you are also an effective absorber of microwaves including bluetooth signals.

As for the health effects, a typical microwave oven produces around 800 Watts of power in order to heat small quantities of food. A bluetooth device for a mobile phone or similar will have a typical power of at most a few milli-Watts. I don't think there is too much danger of you cooking yourself. If there were any danger from this then you'd best be getting rid of your mobile phone entirely, since mobile phone signals are orders of magnitude stronger.


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