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
Walter Janka 1932 he undertook a type setting apprenticeship. In 1930 Walter Janka became an Organisation Leader, and then a Political leader of the Young Communists (KJVD / "Kommunistischer Jugendverband Deutschlands") for the Chemnitz sub-region. After his elder brother, , had been murdered by the Nazis, Walter himself was imprisoned by the Gestapo. He was remanded in custody in Chemnitz and in Freiburg before being convicted of preparing to commit high treason. After 1 years of imprisonment in Bautzen prison, he spent a six-month term in Sachsenburg concentration camp. Finally, in 1935 he was deported to Czechoslovakia. In 1936 Janka went to