Now in 2010 the "chalk board" or black boards can be replaced with projected computer displays, that still allow the teacher to draw and write immediate information on the board but also allow for movies, photos and computer animations to be put on the board. These modern systems require no chemical markers or dusty chalk.
They can store the information written on them for later retrieval or editing. They can be erased instantly, and completely cleanly because the "writing" is just light. Our children deserve the cleanest, clearest, best technology every day, because every day there is more material for them to learn.