Colored Sparks

Usually, the color of a spark formed by an incandescent particle is controlled by its temperature according to gray body radiation. With the help of low boiling metals, gas phase combustion and consequently element-specific emission can be achieved. Here, we report on a detailed discussion of colored sparks in the context of models given in literature and extend the achievable colors of sparks to blue (tellurium) and bright orange (sodium on silica). To the best of our knowledge, we present the first color-changing sparks based on appropriately sized erbium powder. These sparks switch their combustion behavior between surface combustion and gas phase combustion, accompanied by a change between orange and green emission. The color of the sparks has been investigated by long-time exposure and time-resolved emission spectroscopy. Finally, a formulation for a smokeless sparkling fountain based on red-orange diamond sparks and color-changing and branching erbium sparks is presented.