Each year, tons of oil can be spilled into the ocean. Whether it comes from an oil tank spill, a leak that occurs during offshore drilling, or even natural seeps that occur within the ocean, oil spills can cause grave environmental and economic damage to marine and coastal ecosystems. When an oil spill occurs, the oil that floats on water will usually spreads out rapidly across the water surface to form a thin layer called an oil slick. As the oil continues spreading, the layer becomes thinner and thinner, eventually turning into a thin layer called a sheen. Managing and predicting the spread and path of oil is often very difficult for first-responders and clean up crews, however, a newly developed computer model holds promise to helping scientists track a spill. U.S. Geological Survey scientists developed the model as a way of tracking the movement of sand and oil found along the Gulf of Mexico since the Deepwater Horizon oil spill.