Early classroom blackboards were made from which natural material?
- Polished marble
- Baked clay tiles
- Seasoned teak wood
- Thin slate stone
Show answer and solution
Correct answer: D. Thin slate stone
1. Early blackboards needed a smooth, hard, dark surface for chalk.
2. Thin sheets of black or dark grey slate stone were used.
3. Marble, wood and clay tiles were not the original material.
_Source: Wikipedia, Blackboard, lead section_