Fis forFats and oils
Fats and oils are a group of substances that do not dissolve in water. Both fats and oils are the same kind of chemical, but generally something is called an oil if it is liquid at room temperature, and a fat if it is solid at room temperature. Some kinds of fats and oils are edible and can be used in cooking, while others are used as fuel for things like cars. The picture is of some stock cooling, and quite clearly shows a layer of fat sitting above the watery stock.