Identification

• The density of liquid water at 39 degrees Fahrenheit is 62.4 pounds per cubic foot or (in metric measurement) one gram per cubic centimeter. To calculate the specific gravity of two different liquids, weigh them to determine their mass, divide the mass of each by its volume to find its density, then divide the density of each by the density of water to find their specific gravity.
  
  

Features

• If one liquid has higher specific gravity than another, it is more dense. Two liquids with equal specific gravity are equally dense. Since density can vary with temperature, specific gravity should always be defined using the density of water at a specific temperature. According to Engineering Toolbox, 39 degrees Fahrenheit is the most common reference point.
  
  

Fun Fact

• Another easy way to compare the specific gravity of two substances is by adding them to water. A substance whose specific gravity is greater than one will sink, whereas a substance whose specific gravity is less than one will float. The specific gravity of water is less than one, so ice floats in water. Try adding the substances you want to test to water to see whether you can guess what their specific gravity will be.