How is that a "black body" emits en every frequency and is not discrete?

Question

When we read about blackbodies, we are never told about the specific material of the cavity. But the frequency curve is smooth,and depends on the temperature (Plank's law). But we know that atoms emit energy by discrete energetic jumps. ¿How can explain that result?

Answer 1

This is one of the best questions I have seen so far.

To keep it simple it is like this.
Line Spectra seen from excited atoms is due to electron jumps within the atom itself.

Stars and Black Bodies have Thermal Spectra - i.e. just how hot they are.

Here is a really good article explaining the theory.
http://www.astronomynotes.com/light/s4.htm