It is a test method to determine the ductile and brittle behavior of materials. The fracture energies of the materials change with the temperature. The breaking energy decreases as the temperature decreases. By making the fracture energy at different temperatures, the transition temperature of the material is determined. This determined value is the temperature at which the material transitions from ductile to brittle fracture. This point is generally defined as the temperature at the point where 50% brittle 50% ductile fracture occurs in the material.