An aerosal is formed by supplying a material in liquid form to a tube (23) and heating the tube (23) such that the material volatizes and expands out of an open end (25) of the tube (23). The volatized material combines with ambient air such that volatized material condenses to form the aerosol. An apparatus (21) for generating such an aerosol, and a method for generating such an aerosol, are also disclosed.