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

How do erasers erase the markings a pencil makes? Furthermore, why can't it erase pen marks?
gpt
Pencil lead is graphite.  Pencil marks are  fine graphite powder solids.  To a small extent the eraser abrades the paper surface while abrading itself. The tackiness of the eraser dust picks up the graphite and it gets rolled into eraser and paper dust boogers.

Ink, on the other hand, is applied as a liquid.  It soaks below the paper surface.  It can also be erased, but only with heavy abrasion that removes a lot more paper.