Oil and water do not mix because they cannot form any chemical bonds with each other. Water is made up of highly charged, hydrophilic compounds (also known as ‘water loving’) while oil is made up of long chains of carbon that are hydrophobic (‘scared of water’). The long chains of carbon that make up oils do not carry a charge and are not attracted to the water molecules. This causes the separation we see in this experiment as well as in our kitchen sinks and oceanic oil spills. Furthermore, the oil will float on top of the water because it is less dense than oil.