Your review of a noise cancellation device on a recent @discovery.ca programme was quite interesting, although the concept and similar but much more expensive devices have been around for many years.
I would like to know how you explain that electromagnetic waves can/cannot be cancelled the same way, i.e., could "anti-laser" or "anti-radio" type of devices be built? There are a number of exhibits at museums and science centres explaining that electromagnetic waves are just like waves of water or arranged toothpicks, implying that electromagnetic waves can easily be cancelled with anti-waves which is pi radian (180 degrees) out of phase.
Also, microwaves cannot escape from a mesh on the door of a microwave oven because the wavelength is much longer. How come sound waves, e.g., a low-pitch voice, can pass through a bug screen, which is much shorter than the wavelength of the sound? TIA.
