**2. Oil spill behavior in marine environments**

The environmental impact of an oil spill will depend on how quickly it spreads. The majority of oils have the propensity to spread horizontally, leaving a "slick"—a smooth and slick surface—on top of the water. Surface tension, specific gravity, and viscosity are factors that influence how easily an oil spill can spread. The degree of attraction between a liquid's surface molecules is measured by surface tension. The likelihood that an oil spill will continue increases with the surface tension of the oil [6–10]. Even without the aid of wind and water currents, the oil will spread if its surface tension is low. Oil is more likely to spread in warmer waters than in extremely cold ones since increased temperatures can reduce a liquid's surface tension [1–8, 11–15].

The density of a substance as compared to the density of water is known as its specific gravity. Most oils float on top of the water because they are lighter than water. However, if the lighter components of the oil evaporate, the specific gravity of an oil spill may rise. Animal fats, vegetable oils, and heavier oils may interact with sediments or rocks at the bottom of a body of water, sink, and form tar balls. The measure of a liquid's flow resistance is its viscosity. The tendency of the oil to settle in one place increases with its viscosity [1, 6, 8, 16].
