《西游记》第四十七回中,唐僧师徒一行要渡通天河,猪八戒想出如下的方法测试河水的深浅：“寻一个鹅卵石,抛在当中,若是溅起水泡来,是浅；若是骨都都沉下有声,是深．”苏晓辉同学来信问：“猪八戒提出的测试河水深浅的方法依据的是什么道理?”下面我来回答这个问题． In the forty-seventh journey of Journey to the West, the mentoring line of the Tang and Tang dynasties was to cross the Tianhe River. The pig ban had come up with the following method to test the depth of the river: “Find a pebble and throw it in it. If it comes from blisters, it is shallow; if it is The bones are all sinking down and down, and they are deep.“ A letter from Su Xiaohui asks: ”What is the reason why the method of testing the depth of the river proposed by the Pig is based on what?" I will answer this question below.