  We present a model of a "thermal" (i.e., a hot bubble) rising within an
exponentially stratified region of the ISM. This model includes terms
representing the ram pressure braking and the entrainment of environmental gas
into the thermal. We then calibrate the free parameters associated with these
two terms through a comparison with 3D numerical simulations of a rising
bubble. Finally, we apply our "thermal" model to the case of a hot bubble
produced by a SN within the stratified ISM of the Galactic disk.
