The infrared frequencies of the electromagnetic spectrum are experienced by our bodies as heat. Any warm object gives off infrared radiation. Remember though, that warm is a relative term; an ice cube is warmer than liquid nitrogen and so gives off more infrared radiation than the liquid nitrogen. Special infrared scanners have been developed, called thermographic scanners, which can “see” infrared radiation and so detect warm or hot spots. Thermographic scanners are used for many tasks, like finding heat leaking from buildings or finding hidden tumors in the body.?

Picture the radiation coming from a fire. A fire radiates many different wavelengths. We see the light from the fire, so it gives off radiation in the visible wavelengths. We also feel its heat, which means it is giving off infrared radiation.