• Question: what makes popcorn pop?

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      Asked by Chaza433 to Anaïs, Peter on 19 Mar 2015.
      • Photo: Peter Maskell

        Peter Maskell answered on 19 Mar 2015:

        good answer here:-

        http://www.popcorn.org/ForTeachers/TeachingGuide/WhatMakesPopcornPop/tabid/88/Default.aspx

      • Photo: Anaïs Pujol

        Anaïs Pujol answered on 19 Mar 2015:

        Hi Chaza433, there was a recent study into Popcorn and what makes it pop. They investigated the temperature at which it would pop. At 170 C, 34% of the kernals had popped, whereas at 180 C 96% had popped. The water inside the kernal is being heated into water vapour, expanding and pushing against the hull of the popcorn. Eventually this causes a fracture and the contents shoot out. this also led them to look at the the popcorn jump, which they recorded with high-speed cameras, in which the popcorn breaks from the shell, a leg shoots out and then forces the popcorn to jump in the air, rotating about 490 degrees – like a somersault from a gymnast.

        Now the “pop” sound that you asked about, this report discovered using a microphone alongside their camera, that it wasn’t down to the leg or the jump, but was associated with the sudden pressure drop from the release of the water vapour and the shell resonates the sound to make the “pop” sound.
        Video https://player.vimeo.com/video/117126919

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