We explain what elasticity is in physics and what the formula for this property is like. Additionally, examples and elastic materials.

What is elasticity in physics?
When in physics we talk about elasticity we refer to the property of certain materials of being deformed under an external force acting on them and then recovering their original shape when said force disappears. These types of behaviors are known as reversible deformations either shape memory.
Not all materials are elastic and those that break, fragment or remain deformed after the action of external force are simply not elastic at all.
The principles of elasticity are studied by the mechanics of deformable solids according to the Theory of Elasticity, which explains how a solid deforms or moves in response to external forces that affect it.
Thus, when these deformable solids receive said external force, they deform and accumulate inside an amount of elastic potential energy and, therefore, also internal energy.
This energy, once the deforming force is removed, It will be what forces the solid to recover its shape and is transformed into kinetic energy, making it move or vibrate.
The magnitude of the external force and the elasticity coefficients of the deformed object will be those that allow calculating the size of the deformation, the magnitude of the elastic response and the tension accumulated in the process.
See also: Inertia
Elasticity formula in physics
When a force is applied to an elastic material, it deforms or compresses. For mechanics, what is important is the amount of force applied per unit area, which we will call effort (σ).
We will call the degree of stretching or compression of the matter deformation (ϵ) and we will calculate it by dividing the movement length of the solid (ΔL) by its initial length (L0), that is: ϵ = ΔL/L0.
On the other hand, one of the main laws that governs the phenomenon of elasticity is the Hooke's Law. This law was formulated in the 17th century by physicist Robert Hooke when he studied a spring and realized that the force necessary to compress it was proportional to the variation in its elongation when said force was applied.
This law is formulated like this: F = ˗kx where F is the force, x the length of compression or elongation, and k a proportionality constant (spring constant) expressed in Newtons over meters (N/m).
Finally, the elastic potential energy associated with the elastic force It is represented by the formula: Ep(x) = ½. kx2 .
Examples of elasticity in physics

The elasticity of materials is a property that we test daily. Some examples are:
- Springs The springs under certain buttons, or that push the bread in the toaster up when it is ready, operate based on elastic tension: they are compressed and accumulate potential energy, then they are released and recover their shape, throwing the bread up. toasted.
- Buttons The buttons on the television remote control operate thanks to the elasticity of the material that composes them, since they can be compressed under the force of our fingers, activating the circuit underneath, and then recover their initial position (stopping activating the circuit immediately ), ready to be pressed again.
- The chewing gum The resin from which chewing gum is made is extremely elastic, to the point that we can compress it between our teeth or expand it by filling it with air and making a pump, counting on it to retain its more or less original shape.
- The tires An airplane, a car, a motorcycle, operate based on the elasticity of the rubber, which once inflated with air, can resist the enormous weight of the entire vehicle and deform slightly, but without losing its shape memory, which is why it exerts a resistance and keeps the vehicle suspended.
Elastic materials
Elastic materials, those capable of recovering their original shape after suffering partial or total deformation are numerous: rubber, rubber, nylon, lycra, latex, chewing gum, wool, silicone, foam rubber, graphene, fiberglass, plastic, rope, among others.
These materials are extremely useful in the manufacturing industry, since endless applications and objects of practical use can be made from them.