Abstract: A fog or haze machine having a reciprocating emission nozzle is provided. More particularly, a fog generating mechanism is provided that includes a heater for heating a fluid provided by a pump and to emit a fog or haze vapor from the heater to outside of the machine. The nozzle is cyclically moved back and forth along an arcuate path and a wave of fog/haze is continuously emitted from the nozzle in an arc outside the machine, via an elongated slot in which a distal end of the nozzle travels.