一、操作的观察用天平称固体和液体的质量 ,尽管原理相同 ,但具体方法不同。一般固体的质量可直接用天平称量 ;而液体的质量必须放在容器里进行称量。步骤分两步 :先称出空容器的质量 m1,然后再称出容器和液体的总质量 m2 ,则待测液体的质量 m =m2 - m1。具体操作步骤为 :( 1) First, the observation of operation We use the balance to weigh the mass of solids and liquids. Although the principle is the same, the specific method is different. The mass of a typical solid can be weighed directly with a balance; the mass of the liquid must be weighed in a container. The steps are divided into two steps: first weigh the empty container’s mass m1, and then weigh the total mass of the container and the liquid m2, then the mass of the liquid to be measured is m = m2 - m1. The specific steps are: (1)