In thermodynamics, properties are classified as extensive or intensive. An extensive property is a property whose value depends on the quantity or size of matter present in the system (e.g., mass, volume, internal energy, enthalpy, heat capacity). An intensive property does not depend on the quantity or size of matter present. Surface tension is a characteristic physical property of a liquid that depends only on the nature of the liquid and temperature, not on the amount of liquid present. Therefore, it is an intensive property.