What is chalk made of?
Q: What is chalk made of?
A: Chalk is a type of limestone made from calcareous (CaCO3) skeletons of tiny planktonic algae called coccoliths.
Q: How did the chalk cliffs form?
A: The chalk cliffs were formed when England was below the equator in a tropical sea during the Upper Cretaceous, when the Earth was even warmer than now.
Q: Is blackboard chalk real chalk?
A: No, blackboard chalk is not real chalk. It is actually gypsum (calcium sulfate).
Q: What do people use blackboard chalk for?
A: People use blackboard chalk for drawing on hard things because it is soft and leaves a mark if rubbed on something hard or rough. It can be used to write on a chalkboard or blackboard and then erased with an eraser or water.
Q: What does tailors' chalk consist of?
A: Tailors' chalk consists of talc (magnesium silicate), which they use to draw on material when making clothes.
Q: How long are sticks of blackboard usually sold in stores?
A: Sticks of blackboard are usually sold in stores at about 5 cm long.
