Beaker (100 ml) or test tube.
Conc. Ammonia water (C), conc. Hydrochloric acid (C).
Put on protective goggles. Keep both substances away from the body.
For better contrast, it is recommended to use a dark (black) background. When ready, open both bottles and hold them close to each other.
We can also drop a little ammonia and a little hydrochloric acid onto a filter paper each and then bring both sheets together in front of the dark blackboard.
A dense, white mist of ammonium chloride is formed.
NH3 + HCl -> NH4Cl + Energy