Surface Area Matters

Surface area measures the total outside skin of a 3D shape. A cube with 2-inch sides has 6 faces, each 4 square inches, totaling 24 square inches. It tells you how much paint covers a wall, how much wrapping paper covers a gift, and how much heat a radiator gives off.

The ratio of surface area to volume drives biology. Small animals have a high ratio and lose heat fast — which is why mice eat constantly. The same math explains why crushed ice melts faster than a single block: more surface area is exposed per unit of volume.