Sparks of KnowledgeMuhammad AhmadAward: Top 100
School: skaneateles high school While creating mandolins in our PLTW Computer Integrated Manufacturing class, our teacher created fixtures to hold the mandolins in place while we sanded the bridge. In order for the fixture to be made, we drilled two screws into two planks of wood which held the bridge snug in the middle. To make the fixture safe for use, our teacher had to cut the sharp tip of the screws off using a rotating grinder. When the rotating grinder touched the screw tip, large amounts of sparks were emitted which made me wonder how they formed? When the grinder hits the screws, it causes small metal particles to be emitted due to the high friction between the two objects. The grinder cuts through the molecules and rubs against them producing heat which when paired with the oxidation of the metal particles which were emitted, also producing heat, causes the particles to become hot enough to glow. This results in the creation of what we know as "sparks". When the rate of cooling exceeds the rate of oxidation, the sparks become invisible to the naked eye. As the sparks fly through air, they splinter based on the distribution of carbon inside the sparks. When carbon dioxide is formed within a spark, the pressure of the gas produces an explosion. By looking at how the sparks form, the way they split, and other properties like how far they travel before they stop glowing, scientists can identify the metal producing the spark. 
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