When you tune your radio, watch TV, send a text message, or pop popcorn in a ... as when radiation is used to kill cancer cells, and other times not, as when we get ...
To fully appreciate the complexity of the world around us, however, we need to rely on human-made devices to provide views of the "invisible" world -- that is, the parts of the electromagnetic spectrum we cannot see without the aid of technology: gamma rays, X-rays, ultraviolet waves, infrared waves, microwaves, and ...