system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does putting water on a grease fire cause a massive fireball?
gpt
The grease is _much_ hotter than the boiling point of water.  When you throw water on the fire, the water flash boils and turns to steam instantly.  This is violent, and forces grease droplets into the air.  The droplets then catch fire, which causes the fireball.