From the perspective of educational methods, this kind of education is a kind of probation education, which arouses children's sense of shame about wasting food by eating children's leftovers in person, and belongs to a hidden educational method.

However, this kind of education may also have problems:

If students have infectious diseases, this kind of education may make the principal catch diseases, such as hepatitis and flu.

(2) If some students don't have enough comprehension ability to arouse the sense of shame, they may mistakenly think that the headmaster just likes to eat leftovers. Or mistakenly think that the principal has no money to buy his own food and can only eat their leftovers. Therefore, in addition to the demonstration, the principal also needs the cooperation of other teachers, and it may be better to do direct education at the class meeting.

A person's appetite is limited. If students generally waste food, or because the canteen tastes not very good, many students have leftovers. The headmaster can't eat all the leftovers just by his mouth and stomach. Eating too much is also easy to get fat, which affects your health.

This kind of behavior is controversial, and some different voices will be heard in society. Many people will think that the headmaster is not putting on a show, and the social impact is not necessarily positive. After all, China is not a society lacking food and clothing.

Personally, I think that if the school canteen wastes food seriously, the root cause is not necessarily that students do not cherish food. Maybe it's because of the bad taste, or because of my aunt who cooks too much. Improving the quality of canteen service from the source may improve the situation of food waste.