Every year when I teach my students about electromagnetism, I take some time to discuss with them the physics of electromagnetic waves (a.k.a. “light”). EM-waves go by another name common to scientists, electromagnetic radiation, and it’s that second word – radiation – which scares the hell out of so many people and makes them vulnerable to all manner of woo.
Case in point, there is a lot of bunk out there concerning EM-radiation and cancer. Specifically, there is a group of folks who try to push the idea that cell phones, power lines, and wi-fi are emitting radiation (called EMFs, or electromagnetic fields) which will give people exposed to them all manner of cancers. I’m here to tell you that this is just plain b.s. – people who make these pseudoscientific arguments do not understand the physics of EMFs, at all.
First off, the physical mechanism which creates an electromagnetic wave (or “EM-radiation” or “light” or “EMFs” – they’re all the same thing) is basically wiggling an electric charge back and forth. This process generates a self-reinforcing set of electric & magnetic fields which form the wave, and the frequency of these waves (which matches the frequency at which the charge is wiggled) is what determines exactly what kind of EM-radiation is created. Depending upon the frequency of the wave, it will fall along what is called the electromagnetic spectrum…
The Skeptical Teacher 