what is infrared ?

Infrared radiation... The light we see with our eyes is really a very small portion of what is called the "Electromagnetic Spectrum." The Electromagnetic Spectrum includes all types of radiation - from the X-rays used at hospitals, to radio waves used for communication, and even the microwaves you cook food with. Radiation in the Electromagnetic Spectrum is often categorized by wavelength. *Short wavelength radiation...is of the highest energy and can be very dangerous (Gamma, X-rays and ultraviolet rays) *Longer wavelength radiation... is of lower energy and is usually less harmful (radio, microwaves and infrared). ....Although infrared radiation is not visible, humans can sense it - as heat.