A spark is an incandescent particle Such sparks may be produced by pyrotechnics, by metalworking or as a by-product of fires, especially when burning wood. In pyrotechnics, iron filings and metal alloys such as magnalium may be used to create sparks.[2] The quantity and style of sparks produced depends on the composition and pyrophoricity of the metal and can be used to identify the type of metal by spark testing. In the case of iron, the presence of carbon is required, as in carbon steel — about 0.7% is best for large sparks. The carbon burns explosively in the hot iron and this produces pretty, branching sparks.

圖片編號： 51526248
拍攝者： Serdex94