Surface area to volume ratio

The surface area to volume ratio tells us how much surface is available relative to that volume. A high ratio means there is plenty of exchange surface for a relatively small amount of living material. A low ratio means each unit of surface must supply a larger volume.

Surface area to volume ratio of a solid: reaction takes place at the exposed surface, where other reactant particles can collide with the solid. Breaking a solid into smaller pieces exposes more surface without changing its total mass or volume. Smaller pieces have a greater surface area to volume ratio, allowing more collisions with the solid per second.