Which property is defined as the ratio of an object's weight to the weight of an equal volume of water?

Which property is defined as the ratio of an object's weight to the weight of an equal volume of water?

• A. Specific gravity
• B. Density
• C. Mass
• D. Volume

Answer: (A)

Specific gravity is the ratio of an object's weight to the weight of an equal volume of water. Because weight tracks mass, this ratio also equals the object's density divided by water's density, so it is a dimensionless number. Under standard conditions, water's density is about 1 g/cm^3, so specific gravity roughly mirrors the material’s density in those units. A value above one means the material is heavier for its volume than water and will sink; a value below one means it would float. This makes specific gravity a handy way to assess buoyancy and identify materials, without dealing with units.

Specific gravity is the ratio of an object's weight to the weight of an equal volume of water. Because weight tracks mass, this ratio also equals the object's density divided by water's density, so it is a dimensionless number. Under standard conditions, water's density is about 1 g/cm^3, so specific gravity roughly mirrors the material’s density in those units. A value above one means the material is heavier for its volume than water and will sink; a value below one means it would float. This makes specific gravity a handy way to assess buoyancy and identify materials, without dealing with units.