Author
Home > Science > What is the Difference Between Bulk Modulus and Young Modulus?

Guilherme Mazui

•3 minutes to read

What is the Difference Between Bulk Modulus and Young Modulus?

🆚 Go to Comparative Table 🆚

The main difference between Young's modulus and bulk modulus lies in the way they describe a material's resistance to deformation. Here are the key differences:

  • Young's Modulus: This is the ability of a material to resist changes in its length under the influence of an external force. It measures the material's stiffness under tension or compression and is represented by the symbol Y. The units of Young's modulus are typically N/m² or pascals (Pa).
  • Bulk Modulus: This is the ability of a material to resist changes in its volume under the influence of an external force. It measures the material's resistance to compressive forces and is represented by the symbol K. The units of bulk modulus are typically N/m² or pascals (Pa) as well.

The relationship between Young's modulus (Y) and bulk modulus (K) can be derived from stress and strain. A material with a high Young's modulus is very stiff and does not change in length easily, while a material with a high bulk modulus does not change in volume easily.

In summary:

  • Young's modulus measures the stiffness of a material under tension or compression.
  • Bulk modulus measures a material's resistance to changes in its volume.

These two moduli are related through Poisson's ratio, which is a measure of the relationship between the longitudinal and lateral strains of a material.

On this page
  • What is the Difference Between Bulk Modulus and Young Modulus?
  • Comparative Table: Bulk Modulus vs Young Modulus

    • Comparative Table: Bulk Modulus vs Young Modulus

    Here is a table comparing the differences between Bulk Modulus and Young's Modulus:

    Property Bulk Modulus Young's Modulus
    Definition Bulk modulus is the ability of a material to resist changes in its volume. Young's modulus is the ability of a material to resist changes in its length along a specific axis.
    Measurement Represents the ratio of volumetric stress to volumetric strain. Represents the ratio of longitudinal stress to longitudinal strain.
    Formula K = Y / (3 * (1 - 2 / μ)), where K is the bulk modulus, Y is the young's modulus, and μ is the Poisson's ratio. Y = (Tensile stress / Tensile strain).
    Applicable Stress Uniform compression, where pressure is applied from all directions. Uniaxial stress, where the deforming force is along a specific direction.
    Units Pascals (Pa). Pa.
    Relation The bulk modulus is related to the young's modulus through the Poisson's ratio. The young's modulus is an intrinsic property of a material, depending on its composition and structure.

    In summary, both bulk modulus and young's modulus are elastic properties of materials, but they differ in how they respond to stress: bulk modulus measures the resistance to volumetric stress, while young's modulus measures the resistance to uniaxial stress.

    Read more:

    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.