The Black Body Radiation

In Physics language, a black body is an object that absorbs light and do not, or wouldn't reflect light. In this case, the light emitted by the black body will be known as black body radiation. Althought the name "black body" indicates to absord light, it also do produce light in a form of thermal radiation.
In a physics laboratory, the closest thing to the black body radiation is the radiation from a small hole entrance to a larger cavity: if the hole is small, it 'absorbs' little energy from the outside and it 'radiates' all the energy from the inside which is black. However, the spectrum (i.e. the amount of light emitted at each wavelength) of its radiation will not be continuous, and only rays will appear whose wavelengths depend on the material in the cavity (see Emission spectrum). By extrapolating the spectrum curve for other frequencies, a general curve can be drawn, and any black-body radiation will follow it. This curve depends only on the temperature of the cavity walls.