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The glassy trace left by lightning

At Great Sand Dunes, lightning can melt sand around its path, leaving structures called fulgurites. The resulting material records intense local heating and cooling, although a glass-like appearance alone does not identify every specimen as a lightning product.

3–7 min

Questions you could explore

  • What clues could help distinguish lightning-formed glass from glass produced in another way?
  • How could the material and conditions at a lightning strike affect the structure of a fulgurite?

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