Speaking of chalk dust, we can't help thinking of those days when we were still at school. Some students sit near the blackboard, teachers gallop on the blackboard, and students are destroyed by dust under the podium. So blackboard chalk is used less and less, which is a good thing for students who are close to the blackboard. Pastel ink is a kind of dust-like particle. Students who are close to the blackboard are affected by pastel ink for a long time, which will not only cause harm to the skin, but also cause skin allergies and other symptoms. At the same time, long-term inhalation of chalk foam also has various hazards to the lungs, and even causes collective respiratory tract infection.
As the saying goes, eyes are the windows of people's hearts, and a little damage will make us miserable. Chalk dust is also harmful to people's eyes. Chalk dust contains a chemical substance. If you accidentally fall into your eyes, it will trigger the eye protection mechanism and shed tears. Tears will react with it to produce an alkaline substance, which will strongly stimulate the eye mucosa. Students are in this environment for a long time, and this cycle is likely to induce various eye diseases and lead to myopia.
In my opinion, the use of blackboard and chalk should be an auxiliary multimedia teaching. In today's social teaching, multimedia teaching has been implemented in many places, and chalk blackboards can be used to supplement multimedia courseware. In this way, the frequency of chalk use will be less, and the harm to teachers and students will be less.