How is a spark created?

  1. On a fundamental level, can anyone explain how a spark is created from scraping a knife along a peice of metal as done by people who want to light fires 'in the wild'?
  2. jcsd
  3. Chegg
    Electrons are removed from the metal causing it to become charged, then a spark may occur even at such a low voltage because of the very small surface area at the edge of a knife.
  4. Drakkith

    Staff: Mentor

    I'm not sure this is correct. From wikipedia on Flint: When struck against steel, a flint edge will produce sparks. The hard flint edge shaves off a particle of the steel that, heated by the friction, reacts with oxygen from the atmosphere and can ignite the proper tinder.

    I think a similar effect is happening between a knife and metal. It generates high friction which produces "sparks".
  5. Yes, I think sparks are actually pieces of the metal heated by friction, and the temperature causes the metal embers to be incandescent.

    I don't think it is an electrostatics phenomenon.
  6. Thank you.
  7. Then how can it be a spark?
  8. "Spark" has (at least) two meanings.
    One is a small incandescent particle.
    If talking about a fire, "spark" means small incandescent particle (of carbon, usually).
    The second meaning of "spark" refers to an electrical discharge.
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