Length is an extensive property because it depends on the size or amount of the substance being measured. As you increase the quantity of the material, its length will also increase proportionally.
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Key Takeaways: Is Length Intensive or Extensive Property?
- Length is an extensive property because it depends on the size or amount of the substance being measured.
- Extensive properties scale with the size or quantity of the material, and length increases proportionally as you have more of the substance.
- Length is not an intensive property because it changes when you combine or divide different parts of a system, while intensive properties remain constant regardless of the system’s size or quantity.
Why is length an extensive property?
Length is considered an extensive property in the context of thermodynamics and other physical sciences because it depends on the size or amount of the system or substance being considered. Extensive properties are those that scale with the size or amount of the material in question. 1
Here’s why length is an extensive property:
- Scaling with size: When you have more of a substance or a larger system, the length increases proportionally. For example, if you have a piece of wire that is 1 meter long, and you join it with another wire that is also 1 meter long, the combined length of the two wires will be 2 meters.
- Additivity: The property is additive for independent subsystems. In the example above, when you join two separate wires, their individual lengths add up to give you the total length of the combined system.
- Volume dependence: Length is often a fundamental component in determining the volume of a three-dimensional object. In three dimensions, volume is an extensive property, and it depends on the dimensions of length, width, and height. 2 Increasing the size of an object will result in a proportional increase in its volume.
- Intensive properties vs. extensive properties: In contrast, intensive properties are those that do not depend on the size or amount of the system. Examples of intensive properties include temperature, pressure, and density. 3 These properties remain constant even if the system is divided or combined.
In summary, length is an extensive property because it scales with the size or amount of the material being considered, and it exhibits additivity when combining independent systems. Extensive properties are essential in the study of thermodynamics and other fields to understand the behavior of large systems and how they change with size.
Why is length not an intensive property?
Length is not an intensive property because it does not remain constant when you combine or divide different parts of a system. Intensive properties are independent of the system’s size or quantity and do not change with the amount of substance present. However, length changes with the size of the system or the amount of material being considered.
Here’s why length fails to meet the criteria for an intensive property:
- Dependence on size: The length of an object or substance is directly related to its size or quantity. If you have a wire that is 1 meter long and cut it in half, each half will now be 0.5 meters long. The length changes when you modify the amount of material.
- Non-additivity: Intensive properties remain constant when you combine multiple parts of a system. For example, if you mix two samples of water, their temperature remains the same. However, if you join two separate wires together, the length of the combined wire is the sum of the individual lengths. This additive behavior indicates that length is an extensive property.
- Scaling behavior: When you scale up the size of a system, the length increases proportionally. For example, if you have a rectangular box that is 1 meter long, 0.5 meters wide, and 0.5 meters tall, doubling the size of all dimensions would make it 2 meters long, 1 meter wide, and 1 meter tall. The length scales with the size of the system, which is a characteristic of extensive properties.
In summary, length is not an intensive property because it changes with the size or quantity of the system. Intensive properties, on the other hand, are independent of the system’s size and remain constant regardless of the amount of substance present.
Further reading
Is Temperature Intensive or Extensive Property?
Is Color Intensive or Extensive Property?
Is Mass Intensive or Extensive Property?
Is Density Intensive or Extensive Property?
Is Hardness Intensive or Extensive Property?
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References
- Foundation, C. (n.d.). Welcome to CK-12 Foundation | CK-12 Foundation. Welcome to CK-12 Foundation | CK-12 Foundation. https://www.ck12.org/section/properties-of-matter-%3A%3Aof%3A%3A-matter-and-change-%3A%3Aof%3A%3A-ck-12-chemistry-basic/
- Volume – Wikipedia. (2022, August 7). Volume – Wikipedia. https://en.wikipedia.org/wiki/Volume
- types of properties. (n.d.). Types of Properties. http://www.eng.usf.edu/~campbell/ThermoI/Proptut/tut2.html