Pea souper

Designed by the Le Maitre Pyrotechnics and Special Effects company in England, the "Peasouper" smoke effect machine creates a low lying fog for stage and other effects uses. It uses a cage of dry ice pellets which are lowered into a bath of hot water (which is kept hot via an internal heating element). The dry ice (frozen/solid carbon dioxide) sublimates into a dense heavy "smoke" which lasts a short while until it dissipates into the atmosphere. The effect creates a rolling cloud of low lying fog which will follow the ground to the lowest point, "rolling" over stairs, stage fronts and other obstacles.