In science and engineering, intrinsic and extrinsic properties are two classifications of matter or objects. In intrinsic property is inherent or innate to the sample, while an extrinsic property is not inherent to the sample.
An intrinsic property remains the same regardless of the conditions under which it is measured. Its value depends on chemical composition and structure. The value of an extrinsic property may change, depending on conditions. It depends on the way external factors affect the sample.
The key to identifying whether a property is intrinsic or extrinsic is to determine whether any factors could change its value. So, a property which may be intrinsic to one object might be extrinsic to another.
Examples of Intrinsic and Extrinsic Properties
For example, a ball’s mass in an intrinsic property. It is not dependent on external factors or forces. In contrast, a ball’s weight is an extrinsic property. It depends on gravity, which is not the same everywhere.
Sometimes whether a property is intrinsic or extrinsic depends on the state of matter. For example, the size of a glass ball (a solid) is an intrinsic property. But, the size of a balloon (filled with a gas) is an extrinsic property, because it depends on temperature and pressure. The color of a shirt may be red (an intrinsic property), but the color of the gemstone called alexandrite may be blue or red, depending on the viewing angle (an extrinsic property).
Whether a property is intrinsic or extrinsic depends on whether you are talking about a particular object or about matter in general. For example, the length of a wooden meter stick is an intrinsic property. Length is an extrinsic property of wood, because wood doesn’t have a set “length” value. Resistance of a particular piece of copper wire is intrinsic, while resistance of “copper wire” is extrinsic because it depends on the wire’s length and diameter. Context matters!
Most mechanical properties are intrinsic properties. Examples of intrinsic properties include:
- Density (of a liquid or solid)
- Specific gravity
- Specific volume
- Melting point
- Boiling point
- Volume (of a liquid or solid)
- Length (mostly)
- Speed and velocity
- Volume (of a gas)
Intrinsic/Extrinsic vs Intensive/Extensive
Intrinsic and extrinsic properties are closely related to intensive and extensive properties of matter. However, the two classification systems do not mean the same thing and are not interchangeable. An intensive property does not depend on the amount of matter in a sample, while an extensive property does depend on sample size. In materials science, an intrinsic property is an intensive property. But, that is not the case in all disciplines.
In chemistry, it’s a bit different because chemistry focuses on matter rather than samples or objects. So, mass is an intrinsic property of a specific item, yet an extensive property of matter.
Intrinsic and Extrinsic Properties in Engineering
In physics and engineering, an intrinsic property is an inherent property of a material or device. An extrinsic property depends on the effects of structural defects, impurities, contaminants, or operating conditions.
- Brown, T. E.; LeMay, H. E.; Bursten, B. E.; Murphy, C.; Woodward; P.; Stoltzfus, M. E. (2014). Chemistry: The Central Science (13th ed.). Prentice Hall. ISBN 978-0321910417.
- Mishra, U. K.; Singh, J. (2008) Semiconductor Device Physics and Design. Springer. doi::10.1007/978-1-4020-6481-4
- Tolman, Richard C. (1917). “The Measurable Quantities of Physics”. Phys. Rev. 9 (3): 237–253.