Black body
From Conservapedia
A black body is an object that absorbs all light radiation incident upon it. Max Planck's investigation of the details of how such objects emit thermal radiation is a landmark in the history of quantum mechanics.
A hot iron bar pulled out of a blacksmith's forge is one example of a black body. The iron may glow red or orange, indicating that some of the energy it emits lies within the visible part of the electromagnetic spectrum.
