Why do popcorn pop ?

Explanation

(i) Endrosperm in corn consits of two types namely soft and hard .
(ii) In popcorn soft endosperm consitutes most part of the grain surrounded by thin layer of hard endosperm . (iii) When heated, the internal starch and protein are converted into gelatinous subtances and when pressure mounts further. the soft endosperm expands and explodes reversing the grain and the gelatinous starch are converted into foam, which readily solidifies outsides and convert into crispy, tasty popcorn.