Bulk modulus

Definition

Bulk modulus is a measure of a material's resistance to uniform compression. It is defined as the ratio of pressure increase to the resulting relative decrease in volume.

5 Must Know Facts For Your Next Test

1. The bulk modulus ($K$) is mathematically expressed as $K = -V \frac{\Delta P}{\Delta V}$, where $V$ is the initial volume, $\Delta P$ is the change in pressure, and $\Delta V$ is the change in volume.
2. Bulk modulus has units of pressure, commonly Pascals (Pa) in the SI system.
3. Materials with high bulk modulus values are incompressible; they resist changes in volume under pressure.
4. Fluids generally have lower bulk modulus values compared to solids due to their higher compressibility.
5. In acoustics, bulk modulus plays a crucial role in determining the speed of sound through a medium.

Review Questions

• What does a high bulk modulus indicate about a material's compressibility?
• How do you calculate the bulk modulus given initial volume, change in pressure, and change in volume?
• Why is bulk modulus important for understanding sound propagation through different media?

Related terms

Young's Modulus: A measure of the stiffness of a solid material, defined as the ratio of tensile stress to tensile strain.

Shear Modulus: A measure of an object's ability to resist shear deformation, defined as the ratio of shear stress to shear strain.

Sound Intensity: The power carried by sound waves per unit area in a direction perpendicular to that area.