Scratch hardness Scratch hardness Scratch hardness tests are used to determine the hardness of a material to scratches and abrasion. The earliest test was developed by mineralogist Friedrich Mohs in 1820 (see Mohs scale). It is based on relative scratch hardness, with talc assigned a value of 1 and diamond assigned a value of 10. Mohs' scale had two limitations; it was not linear, and most modern abrasives fall between 9 and 10. Raymond R. Ridgway, a research engineer at the Norton Company, modified the Mohs scale by giving garnet a hardness of 10 and diamond a hardness of 15. Charles E.
Measuring the Universe Measuring the Universe Measuring the Universe is a performance art work by Slovak artist Roman Ondak first installed in the Pinakothek der Moderne in Munich in 2007. The exhibition stars as a blank white wall and begins to fill when museum guards mark visitors' height along with their name and the current date. It is in the collection of Tate Modern in London, Pinakother der Moderne in Munich and MoMa in New York. The only items required for the installation were a white room and a few black markers. What began as a clean white space has been filled with