Name two advantages of relative density over density in measurement?

Relative density is applied on many cases when dealing with substances, such as specific gravity where the density of any mass (liquid or solid) such as oil or wood is compared to the density of water. It has the following advantages:

1. Gives us a better understanding of the quality of the substance, for example if it is heavier than the same volume of water.
2. Provides with useful data when dealing with a binary mixture, where there are two substances interacting with each other. For example the relative density of oak wood is 0.75 (important to note that relative density has no units) when compared to the density of water, so we can safely assume that oak wood would float on water and not sink.