这种方法系根据阿基米德原理,因为比重计浮在液体中所排开液体之重量始终等于比重计本身之重。液体浓度增大,比重计浸入液体中之体积就减少,反之则增多。这种变化反映在比重计玻璃杆之升降,因而我们研究比重计玻璃杆刻度范围内体积变化的规律,就可以求得比重计刻度校正值。 This method is based on the principle of Archimedes because the weight of liquid discharged by the hydrometer floating in the liquid is always equal to the weight of the hydrometer itself. Liquid concentration increases, the hydrometer immersed in the liquid volume decreases, and vice versa increased. This change is reflected in the hydrometer glass rod lift, so we study the law of scale glass rod scale volume changes, you can find the scale calibration value.