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 Most people first encounter the word "chalk" in school where it refers to blackboard chalk, which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased.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 Inc. distance learning and for conferencing. The company launched Blackboard Mobile in 2009 after having acquired TerriblyClever. The platform provides students with access to teaching and learning content and campus information through mobile applications for iOS, Android, BlackBerry and WebOS devices. Blackboard Mobile allows students to both access course materials, check grades, and participate in discussions, and to access information about campus life and services. The company began providing its Blackboard Connect service in 2008, for use by school districts and higher education institutions to send out mass phone, text and e-mail notifications. The service can be used for routine alerts