text: if a whip breaks the sound barrier, how come it does not make that sonic boom cloud cone?   the clouds appear for the same reason that clouds always form, namely, that the air has cooled to the point that the ambient water vapor condenses.  the first site explains in detail why the clouds are merely an effect of aerodynamics and pressure and not a literal visualization of a barrier penetration. the second link explains it further and then provides links to some really cool pictures of the effect.