---

Compressibility

---

Quick
The reciprocal of the bulk modulus is called the compressibility and is denoted by k.


Details

The reciprocal of the bulk modulus is called the compressibility and is denoted by k. Note that bulk modulus is also called k as defined in mechanics of materials in the lesson Bulk Modulus and Dilation. From Eq6 from the lesson Bulk Modulus and Dilation:

(Eq1)

k = 1 B =  − ΔV/V0 Δp B =  − 1 V0 ΔV Δp

Compressibility is the fractional decrease in volume, −ΔV/V₀, per unit increase Δp in pressure. The units of compressibility are those of reciprocal pressure, Pa⁻¹ or atm⁻¹.

Materials with small bulk modulus and large compressibility are easy to compress; those with larger bulk modulus and smaller compressibility compress less with the same pressure increase.