Confusion about how black bodies radiate all frequencies

[Olivia Fong 2k]

Hi! I'm confused about how black bodies are able to emit all wavelengths. From my understanding, they are composed of different elements so they are not limited to absorbing/emitting different wavelengths, yet aren't there still quantized energy levels of each element that can only correspond to so many frequencies of light? And how do the transitions in energy levels interact with each other to cause them to emit all frequencies of light? Thank you :)

[Jessica Johal 2B]

You are correct, which is why Professor Lavelle mentioned that there is no such thing as a true black body. It would be impossible to absorb and emit all frequencies of light, although some things can come close to this.

[Levy Shaked]

Again, yes—no such thing as a true black body but, for a substance composed of several heavy elements each with many energy levels, the sheer number of possible energy-level transitions that can then be further combined across elements allows very nearly any wavelength to be produced. With respect to how exactly electron energy-level transitions can combine across elements, this has to do with metalic bonding. Both pure metals and alloys exhibit a type of structure where valence electrons are delocalized between the individual atoms, and because these electrons are essentially passed freely between a multitude of nuclei, individual atomic orbitals begin to overlap to form continuous bands of energy levels throughout the solid. More and more atoms with more and more energy levels (and more and more elements, each with their own set of quantum levels) means these bands increase in quantity and get packed closer and closer together to the point where there are virtually an infinite number of possible energy bands in the solid. This allows for such a large possibility of transitions that makes the emission spectrum virtually continuous.