The Cornstarch Flamethrower
  Igniting cornstarch powder is a classic physics demonstration that showcases the rapid conduction of heat for a material in which the surface area is greater than the volume of its constituent particles. Including such a demonstration in a physics "magic show" for the general public presents certain challenges such as reproducibility and consistent crowd appeal. A simple but effective design for widely scattering cornstarch dust over a flame breaches these challenges and always results in consistently large, crowd-pleasing fireballs; so much so that the resulting demonstration has been dubbed the "cornstarch flamethrower." A small-scale version may also be used effectively for classroom instruction. 
Thomas Concannon
physics.pop-ph physics.ed-ph