system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do ceiling fans collect dust when they're constantly in motion?
gpt
The air moving over the blades actually creates a static electric charge.  Like rubbing a balloon against a sweater, this creates an attractive force between the charged blades and dust in the air.

This build-up of static charge is the predominant effect causing the dust to collect over time.