bulk modulus
Numerical constant that describes the elastic properties of a solid or fluid under
pressure from all sides. It is the ratio of the
tensile strength or compressive force per unit surface area to the change in volume per unit volume of the solid or fluid and thus is a measure of a substance's ability to resist
deformation. Its units are newtons per square metre (N/m
2). Matter that is difficult to compress has a large bulk modulus; for example, steel has a bulk modulus of 1.6
ยด 10
11 N/m
2, three times that of glass (i.e., glass is three times more compressible than steel).
For more information on bulk modulus, visit Britannica.com.
Britannica Concise Encyclopedia. © 1994-2012 Encyclopædia Britannica, Inc. All rights reserved.