A device for imparting a rocking motion to a rockable object having a curved bottom surface comprises a wedge-shaped housing and a reciprocating drive mechanism. The wedge-shaped housing comprises an upper housing having an upper surface configured for contacting the curved bottom surface of the rockable object, the upper housing having a proximal end and a distal end; a lower housing having a base configured for sitting on a surface, the lower housing having a proximal end and a distal end; and a hinge portion hingedly joining the proximal ends of the upper and lower housings. The reciprocating drive mechanism alternatingly moves the distal end of the upper housing upward to an extended position and downward to a retracted position.