Like natural snow, technical snow consists of nothing more than water and air. In the case of mechanical production using lances and fan guns, natural snowfall is imitated. The so-called nucleators produce a hydrogen-air mixture that expands in the atmosphere, allowing nuclides (= snow cores) to emerge. At the same time, the nozzles atomize water into fine droplets, which combine with the nuclides and freeze into small snow crystals on their way down to the ground. The main requirements for technical snow production are the lowest possible air temperature and humidity. The combination of both variables results in the so-called wet-bulb temperature, used by snow-making technicians all around the world. Water temperature too plays an important role in snow-making, and ideally should be slightly above freezing point.