Microwave radiation is still associated with energy levels that are usually considered harmless except for people with pace makers. However, there is some concern that intense microwave radiation have a long exposure time may be harmful in certain circumstances. Moving down to shorter wavelength radiation, there is the infrared region. This region of the spectrum is sometimes called heat waves . Infrared radiation is energetic enough to affect molecular activity.
All warm objects radiate infrared radiation.
Special infrared detectors are used to detect heat energy being emitted as a result of metabolic activity. Heat coming off machines and heat producing engines were detectable as infrared radiation. Infrared radiation has enough energy to affect molecular motions of substances. Instruments using infrared radiation were designed to determine the identity and structure of compounds. It is interesting that the only part of the electromagnetic spectrum that is viewable by the naked eye is a very narrow band if visible radiation.