Since liquids are generally kept in some kind of rigid container,the expansion takes place at the upper surface only,so that the level of the liquid rises as its temperature is increased and falls with a decrease in temperature.

• 由于液体一般是保存在某种坚固的容器中的，膨胀只在液体的表层发生，因而液面随着温度增加而升高，随着温度下降而下降。