NCFE Physical Science Practice Exam

In a scratch test, a softer material will be scratched by harder materials because of the fundamental properties of hardness and material interaction. Hardness is a measure of a material's ability to withstand scratching, indentation, or deformation when in contact with another material. When two materials are pressed against each other, the harder material can create an impression or scratch on the surface of the softer material, which cannot resist the applied force due to its lower hardness.

This principle is the basis for various hardness scales used to categorize materials, such as the Mohs scale. In this context, if a material is defined as softer, it simply means that it has a lower resistance to deformation or scratching compared to the harder material. Therefore, when subjected to a scratch test, the outcome will unequivocally show that the softer material will be marked or damaged by the harder one, confirming that it is indeed scratched by harder materials.