Surface energy is the work per unit area done by the force that creates the new surface.
From the table, the surface energy is very large for Cast Iron,which is a brittle material that shatters without much warning. Since brittle fracture creates new surfaces, the surface energy varies inversely with the tendency to brittle failure. At high temperatures there is a tendency for glasses to change shape into a sphere. If the glass changes, from a cylinder of length 100 mm and diameter 20 m m, into a sphere, find the energy released. First find the radius of a sphere with the same volume as the cylinder.