Specific gravity is a way of relating the density of an object to the density of water to determine whether or not the object will float. The formula for specific gravity is given below:

If an object's specific gravity is less than one,
then the object will float. If the object has a specific gravity of
greater than one, it sinks. So dense objects sink in water and less
dense objects float.

**Importance of Specific Gravity**

Specific gravity is a very important concept in the water/wastewater
field. The specific gravity of a substance will determine where
a compound can be found in water in case of a spill.

Let's consider gasoline. The density of gasoline is 0.6 g/mL and the density of water is 1.0 g/mL. So the specific gravity of gasoline is:

Since its specific gravity is 0.6 (less than 1), gasoline floats in water. So when a ship leaks gasoline into the water, the gasoline stays at the top of the water.

In contrast, the specific gravity of palmalive is 1.1, so it sinks in water.