An Investigation of Blackboard Surfaces : Surface Roughness of Blackboard surface materials

摘要

In This paper, by measurements and statistic analyses, surface roughness of the blackboard surface materials are studied. Conclusions: (1) Unit of height in surface roughness curve of each blackboard surface materials is 1/1000 mm. (2) Surface roughness of each blackboard material-hard finished, wooden or steel board, enameled glass board, enameled steel board, plastic boad or sheet-differ from each other. (3) Indexes of surface roughness are mutually corelated.