Hardness Hardness Hardness is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. Some materials (e.g. metals) are harder than others (e.g. plastics, wood). Macroscopic hardness is generally characterized by strong intermolecular bonds, but the behavior of solid materials under force is complex; therefore, there are different measurements of hardness: "scratch hardness", "indentation hardness", and "rebound hardness". Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are ceramics, concrete, certain metals, and superhard materials, which can be contrasted with soft matter. There are three
Carlo Janka Carlo Janka Carlo Janka (born 15 October 1986) is an alpine ski racer from Switzerland. Born in Obersaxen, in the canton of Graubünden, he had the winter sports facilities right in front of his home. Janka has won gold medals at both the Winter Olympics and the World Championships, as well as one World Cup overall title, one discipline title and also, one unofficial alpine combined title. In 2013, Janka set a World Cup speed record in the downhill part of the super combined event in Wengen, Switzerland. He reached a maximum speed of on the "Haneggschuss", the fastest section