Patent ID: 7296466

Claim:
A method for measuring specific gravity using an underwater weighing container the underwater weighing container comprising a body having a side wall defining a hollow space, an upper open end, and a bottom open and; and a bottom plate placed in the body which is movable both upwardly and downwardly along an axial direction of the body in a given range between the upper open end and the bottom open end for holding a solid specimen, wherein the underwater weighing container receives a weight or a buoyant force of the solid specimen immersed in a reference liquid, the method comprising: weighing the solid specimen in air; weighing the underwater weight container without the solid specimen while the underwater weight container is immersed in a reference liquid; and weighing the underwater weight container and the solid specimen while the underweight container with the solid specimen is immersed in the reference liquid, wherein the solid specimen is placed on an upper surface of the bottom plate so that the weight of the solid specimen is applied to the bottom plate if a specific gravity of the solid specimen is greater than that of the reference liquid, or the solid specimen is inserted underneath the bottom plate so that the buoyant force from the solid specimen is applied to the bottom plate if the specific gravity of the solid specimen is smaller than that of the reference liquid.