system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does the air shimmer over hot things (i.e. fire, pavement, a warm summer day)?
gpt
over hot things the air get warmer, when the air gets warmer it expands resulting in lower pressure. remember light travels in various speeds in different mediums(The denser the medium the slower it travels) therefore when light enters from the higher pressure air to the lower pressure its speed decreases and its path changes, this is refraction. That's why you see the air shimmering over hot things
This is also called the 'mirage effect'.