Why do erasers remove pencil marks?
Short answer
A pencil leaves graphite on the surface and in the upper fibers of paper. When an eraser rubs the mark, the graphite sticks to the eraser more readily than it sticks to the paper, so it is lifted away.
How it works
Graphite in a pencil is made of thin layers of carbon. When you write, small graphite particles are left on the paper’s surface and in gaps between its fibers.
Rubbing an eraser creates friction that lifts the particles. Soft rubber or plastic in the eraser takes up the graphite, and the used material often breaks into crumbs that can be brushed away.
Key point
Ink often sinks into the paper fibers, so it cannot be removed as easily as graphite. Rubbing too hard can remove or damage the paper surface as well as the mark.