How does a seed turn into foam?The explosive physics inside a tiny kernel

From the show

Science Around You

Popcorn works because every kernel is a tiny, sealed pressure vessel waiting to burst. When heat is applied, the water inside turns to steam, cooking the starch into a gelatinous goop while pressure builds to critical levels. Once the hull fails, that superheated starch expands instantly and solidifies. It is essentially an edible explosion frozen in time.