Why Are Infrared Rays Called Heat Waves?

Infrared rays are some of the many electromagnetic rays we experience in our everyday lives. The term infrared is often associated with heat or referred to as being thermal, but not all infrared rays emit heat in the way we understand it.

Electromagnetic Spectrum

Infrared rays fall along the electromagnetic spectrum between visible light and microwaves. The different segments on this spectrum are distinguished by their unique wavelengths. Just as rays that fall along the visible light spectrum emit the colors we see, rays on the infrared spectrum emit heat, or temperature.

Temperature

Something does not necessarily have to be hot to emit infrared waves, it simply must produce a temperature. This may make the term heat waves confusing, as even ice can emit infrared waves. Infrared waves allow us to assess thermal energy, or the heat something emits. However, this term heat refers to an object's temperature rather than its actual hotness.

Wavelength

There are different temperatures and thus there must be different infrared rays. The heat, or temperature, emitted by infrared rays is determined by the length of the infrared wave. The longer the wave the hotter the ray, whereas shorter waves produce less heat, yet still produce heat.

References

• NASA: The Electromagnetic Spectrum: Infrared Rays