Popped corn kernels are the result of heating corn kernels until they burst open. Each kernel has a hard outer shell, called the pericarp, which traps moisture inside. When heated, the moisture turns into steam, creating pressure until the kernel explodes, transforming it into the fluffy snack we enjoy. This process typically occurs at temperatures around 356°F (180°C). The popped corn expands to about 20 to 50 times its original size. Popcorn is a popular snack at movie theaters and is often flavored with butter, salt, or other seasonings for added taste.