When it hits a rough surface, the light scatters in many directions
When light hits a smooth surface, like a mirror, it bounces off in a single direction. This is because the surface of the mirror is very smooth and uniform, so the light doesn't have anything to scatter off of. When light hits a rough surface, like paper, the light scatters in many directions. This is because the surface of paper is very uneven and has lots of tiny bumps and indentations. The light particles bounce off of these irregularities in different directions, causing them to scatter.