system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how does corn pop into popcorn, and are there other seeds with this ability?
gpt
The water content of kernel expands as it is heated, turning to steam. When the internal pressure gets high enough the kernel explodes and the steam is released, leaving the starches crispy and perfect for crunching.

As to other seeds, it depends on hull thickness/toughness, water content, and potentially oil content. While there are other seeds you could get to "pop" they wouldn't have the same texture as popcorn.