There is a magnet that attracts iron on the blackboard. Blackboard doesn't mean blackboard. Traditionally, it is a plane that can be written repeatedly with chalk. The board is relatively hard and is mostly used for teaching. Blackboards are usually made of wooden boards or frosted glass, and you can write on them with specific writing materials such as chalk. Most of them are black, dark green, white or beige.

Blackboard introduction

Blackboard doesn't mean blackboard. Traditionally, it is a plane that can be written repeatedly. The board is relatively hard and is mostly used for teaching. Mostly black, dark green and white. Before the invention of writing, people found that charcoal can be used for painting, and some ancient murals can be found in some ancient caves in Europe. The rock wall painted with these murals can already be called a blackboard in the traditional sense.

In ancient China, an object called sand table was often used in teaching, and hard wood was used to write on the sand repeatedly. However, due to the softness of sand, it cannot be regarded as a blackboard. The blackboard is used for music. As the name implies, this kind of blackboard is called music blackboard. One of the singing blackboards was successfully developed by Soviet scientific and technological personnel.