Chalk It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are then consolidated and compressed during diagenesis into chalk rock. Most people first encounter the word "chalk" in school where it refers to blackboard chalk, which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased. Blackboard chalk manufacture now may utilize mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum (calcium sulfate). While gypsum-based blackboard chalk is the lowest cost to
Blackboard Learn LLC and were developing a software product that would power online education and be scalable for wider institutional application. At the same time, Matthew Pittinsky and Michael Chasen formed Blackboard LLC and were contracted to help lead the formation of the Educause IMS standards group for online education technology. The two groups merged to form Blackboard Inc., which then developed the Blackboard Learning System. In 2015 the company announced a major upgrade to the user experience, called Ultra. According to company statements, Ultra is to be an optional user interface sitting on top of the existing Learn 9.1 architecture. In