初中物理第一册书中,《液体的压强》一节课文后编有一道练习题:“水坝下部为什么要比上部修得厚?(”课本扉页有彩照)常见这样的回答:由于水压强随着深度的增加而增大,水坝下部比上部受到水的压强大,为了防止坝被水压坏,所以坝的下部比上部修得厚。这是书的编者或教师可期望的回答,但是它并不符合实际.以 In the first volume of junior high school physics, there is an exercise after the text of “Liquid Pressure”: “Why is the lower part of the dam thicker than the upper part?” ("There is a color photo on the title page of the textbook) Commonly such an answer: As the depth increases, the lower part of the dam is subjected to a greater pressure than the upper part. In order to prevent the dam from being damaged by water pressure, the lower part of the dam is thicker than the upper part. This is an expected response from the book’s editor or teacher, but it is not realistic