Abstract: A bubble-forming device is constructed of a shallow dish-shaped bubble engaging disc having a central opening spaced apart inner and outer circular walls forming an open ended chamber of annular cross-section located on the convex side of the disc, the open end of the chamber being in communication with the opening in the disc, the inner wall having a lateral aperture in communication with the annular chamber and having an air supply inlet opening concentric with the open end of the chamber and the opening in the disc, a detachable cover covering the opening in the disc and having an aperture which is located so that air entering the chamber via the inlet opening and the lateral aperture emits from the aperture in the cover over the surface of said disc.