Categories: Science

Young’s Modulus| Elastic modulus| Modulus of Elasticity

Young’s Modulus, also known as the elastic modulus or modulus of elasticity, is a measure of the stiffness of a material. It quantifies the ability of a material to deform elastically under an applied load. Young’s Modulus is named after the 18th-century scientist Thomas Young, who first introduced the concept.
Mathematically, Young’s Modulus (E) is defined as the ratio of stress (σ) to strain (ε) in a material undergoing elastic deformation. The relationship is expressed by Hooke’s Law, which states:

σ=E⋅ε

Where:

σ is the stress (force per unit area),
E is Young’s Modulus,
ε is the strain (relative deformation or change in size).

In terms of units, Young’s Modulus is measured in pascals (Pa) or newtons per square meter (N/m²) since stress is force per unit area and strain is a dimensionless quantity.

Young’s Modulus represents the slope of the linear portion of the stress-strain curve in the elastic region of a material. It describes how much a material will deform under a given load and is a crucial parameter in engineering and materials science. Materials with higher Young’s Modulus values are stiffer and deform less under a given load, while materials with lower values are more flexible and deform more.

Daily Life Examples of Young’s Modulus

Number	Material	Young’s Modulus (GPa)	Analogy
1	Rubber Bands	0.01 – 0.1	Stretch easily
2	Steel Springs	200 – 210	Resist bending, like springs in a mattress.
3	Aluminum Foil	68	Bendable but retains some rigidity
4	Wooden Pencils	10 – 20	Balanced flexibility
5	Concrete Structures	25 – 40	Rigid and resistant to deformation
6	Plastic Drinking Straws	2 – 3	Easily bendable
7	Nylon Ropes	2 – 4	Strong yet flexible
8	Glass Panes	70 – 90	Rigid and resistant to bending, like glass.
9	Human Hair	0.002 – 0.02	Easily stretched
10	Copper Wires	100 – 400	Maintains shape under tension

Stiffness of a material vs. Young’s Modulus

The terms “stiffness of a material” and “Young’s Modulus” are related concepts, but they are not exactly the same. Stiffness is a general term that describes a material’s ability to resist deformation when subjected to an applied force. It is a property that can be characterised by various measures, and Young’s Modulus is one of them.
Young’s Modulus (E) is a specific material property that quantifies its stiffness in the elastic range.

Stiffness of a Material	Young’s Modulus
Describes a material’s ability to resist deformation.	A specific measure of a material’s stiffness in the elastic range.
A general term indicating how much a material bends or deforms under an applied force.	Denoted by the symbol E.
Can be expressed in various ways, not limited to a specific numerical value.	Represents the ratio of stress to strain in the linear elastic region.
	Provides a numerical value indicating how much a material deforms under a given load.
	Standardized and specific, often used in materials science and engineering.