• Question: What makes popcorn pop?

    Asked by sodiumpolyacrylate to David, James, Mike, Suze, Will on 16 Jun 2011.
    • Photo: David Ingram

      David Ingram answered on 15 Jun 2011:

      there is a small amount of water stored in the kernel of the seed which boils causing turning to steam. steam has 1000 times more volume than water so the pressure in the kernel rises rapidly and there is a small explosion – called an overpressure explosion.

      This makes the pop and turns the kernel inside out

    • Photo: James Marrow

      James Marrow answered on 15 Jun 2011:

      Dave’s right.

      I used to do an experiment with my students to understand random variation of properties – we’d weigh individual kernels of corn with a very sensitive set of scales, and then pop them one by one in a test tube. We’d then weigh them again, and look at how much weight they had lost (through the steam). You get a lot of variation from kernel to kernel, but if you look at a large number of tests from two different types of popcorn, you can use the averages to see if they are different or not. This is an example of how statistics is used to look for small differences – a very common need in science.

    • Photo: Mike Dodd

      Mike Dodd answered on 15 Jun 2011:

      I didn’t know how popcorn popped, so thanks David and sodiumpolyacrylate (for asking the question) 🙂

    • Photo: Suze Kundu

      Suze Kundu answered on 15 Jun 2011:

      I’ve learned something new today!

    • Photo: William Eborall

      William Eborall answered on 16 Jun 2011:

      Pop.

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