text: does anyone know where to find the 'recipe' for touch powder? touch powder is a mixture of chemicals which is left to dry after mixing. once dry it is white, and when touched in powder form it will turn the area you have touched it with purple. concentrated aqueous ammonia, iodine, filter papers, spatula  method -  in a beaker add some crystals of iodine to some of the ammonia solution and allow to react for a couple of minutes.  remove some of the precipitate to a piece of filter paper and spread evenly across paper.  let dry in a sheltered place.  once dry simple contact will cause it to explode    safety - note that this substance is an explosive.  make sure no large lumps are left to dry on the filter paper.  don't make too much touch power in one batch, and don't try to store it for later use.  avoid getting these chemicals on skin or in eyes.  explanation - the precipitate created is nitrogen tri-iodide.  this compound is very unstable and is extremely sensitive to pressure, and will explode at the slightest provocation (much like grade 9 students!)  notes - the ingredients in this demo are reasonably easy to get hold, even outside of the laboratory,  of so i would suggest not being too forth coming about their exact nature.