Extraction of vegetable oils and fats.
© Science Museum / Science & Society Picture Library
Exhibit illustrating the sources and methods of extraction of vegetable oils and fats, shown together with a model of a screw expeller. At normal temperature, an oil is liquid and a fat is solid. They are usually found in the fruit or seeds of plants located in the tropics. They can be extracted either by being pased through a screw expeller, or they can be crushed and the oil extracted by a hot solvent They are used for food and for making items such as soap, cosmetics and plastics.