[ \gamma \approx 2\alpha ]
1. Introduction Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature. Surface expansion (or area expansion) refers specifically to the increase in the area of a solid object (typically a thin sheet or a plate) when its temperature rises.
The hole expands as if it were made of the same material. The area of the hole follows the same surface expansion law.