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How to Cut Glass With a String Under Water

Cutting a glass bottle or other piece of glass using nothing more than a string is a fun trick to show your friends. Watch their faces as you light the kerosene-soaked string wrapped around a bottle, submerge it into cold water and break the glass along the line of the string. This trick never fails to impress most people who have not seen it before, and it is also a great way to safely cut glass.

Things You'll Need

  • Glass bottle
  • Cotton string
  • Kerosene
  • Lighter
  • Bucket of cold water
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Instructions

    • 1

      Wrap the string around the bottle you wish to cut and tie it off snugly to the surface of the glass.

    • 2

      Remove the tied string loop. Soak it in kerosene then place it back onto the bottle.

    • 3

      Light the string and allow the flame to burn evenly around the bottle until the flame burns out.

    • 4

      Submerge the bottle into the bucket of cold water just after the flame has finished burning. The drastic temperature difference between the hot glass and the cold water will cause the glass bottle to break only along the line on which the burning string sat.