system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 How mirages work

What are they? When do they occur? Ay other interesting stuff?
gpt
You know how when there's a cookout and you look just above the grill you can see distorted wavy lines in the air?

A mirage is that same thing in the desert, where the distortion is so strong that a bit of the blue sky appears mixed up with what should be the sand, so people believe they are seeing blue water on the ground.