Chapter 3 - Exercises: Things Engineers Think About - Page 150: 1

Inside each kernel of popcorn is a tiny droplet of water surrounded by a hard shell called a hull. As the popcorn is heated, the water turns into steam, which builds pressure inside the kernel. When the hull can no longer contain the pressure, popcorn pop.

Inside each kernel of popcorn is a tiny droplet of water surrounded by a hard shell called a hull. As the popcorn is heated, the water turns into steam, which builds pressure inside the kernel. When the hull can no longer contain the pressure, popcorn pop.