system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:What is happening when you see the air ripple on a hot day?
gpt
Light travels at different speeds through different mediums, and as the density of the mediums vary. The air is being heated at different rates between you and the horizon creating different air densities, like ripples on the surface of a river. Light from the horizon refracts as is passes through the different boundaries of densities, just like looking down into a river bed or sea shore through the water.