Youngs modulus is a mechanical property of solid materials that measures the tensile or compressive stiffness when the force is applied lengthwise. It is a measure of the stiffness of an elastic material, defined as the ratio of stress to strain. Youngs modulus is commonly measured in the International System of Units (SI) in multiples of the pascal (Pa) and common values are in the range of gigapascals (GPa).

Youngs modulus is defined as the ratio of the stress (force per unit area) applied to the object and the resulting axial strain (displacement or deformation) in the linear elastic region of the material. It quantifies the relationship between tensile or compressive stress (force per unit area) and axial strain (proportional deformation) in the linear elastic region of a material. Youngs modulus enables the calculation of the change in the dimension of a bar made of an isotropic elastic material under tensile or compressive loads.

The Youngs modulus is very important to doctors and scientists as this constant can tell them when a structural implant will deform. This will let them know how to design a piece mechanically for use in a body. Youngs modulus is also used to predict the deflection that will occur in a statically determinate beam when a load is applied at a point in between the beams supports.

Examples of Youngs modulus values for different materials include:

• Rubber: low Youngs modulus, meaning it increases in length quickly when pressure is applied.
• Steel: high Youngs modulus, meaning it is difficult to stretch or compress.
• Rocks with low Youngs modulus tend to be more ductile and rocks with high Youngs modulus tend to be more brittle.

In summary, Youngs modulus is a measure of the stiffness of a material, defined as the ratio of stress to strain. It is commonly measured in the International System of Units (SI) in multiples of the pascal (Pa) and is used to predict the deformation of a material under tensile or compressive loads.