Text Structure Analysis: What Causes Popcorn to Pop?

Thousands Of Pictures

7 When the kernel gets very hot — above 100 degrees Celsius (212 degrees Fahrenheit) — the water inside hits its boiling point and turns to steam. The steam creates a vapor that forces its way into the endosperm. The endosperm melts into a thick substance, like bread dough. The vapor puts pressure on the hull as the heat is increased. Eventually, the hull cannot take the heat anymore. The kernel has to explode.

8 The starch cools very quickly as soon as the kernel explodes. It turns into a spongy white flake of popcorn. After this popping process, the fluffy corn is twice as large as the original kernel.

9 Virot and Ponomarenko used high-speed cameras to capture this process very closely. They used the cameras to observe kernels popping on a hot plate. They turned the heat and placed a few kernels on the very hot surface. The cameras took thousands of pictures every second.