Why is a pencil lead made of graphite? Why do they write on the blackboard with chalk?

Graphite is used because it is soft and leaves a trace on paper. Peeling pieces of mineral leave a mark on the board.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.