Linear dilation


In order to understand linear dilation, it is very important to understand that most bodies have the ability to dilate. At the moment in which a body increases its temperature , the particles that make it up have the ability to move with a higher speed, and for this reason, they will need to create a larger space to be able to move properly, this is where it comes in. the term linear dilation , an increase in volume longitudinally.


What is linear dilation?

Linear expansion is an increase that occurs in the volume of a material but that takes place in a single direction, specifically in its length , which makes it a unique process in solids that are subjected to heating .

  • What does it consist of
  • Characteristics of linear dilation
  • Linear expansion coefficient
  • Importance
  • Examples of linear dilation

What does it consist of

Before establishing the meaning of linear dilation it is important to consider what dilation itself implies . This is a change that can occur in terms of the dimensions that bodies that are in solid , liquid or gaseous state can experience at the moment in which the temperature undergoes a variation but at the same time maintaining the pressure constantly.


This phenomenon consists of the increase in the volume of a body which is caused longitudinally . Linear expansion is a process that can only occur in materials that are in a solid state of matter, as they must be subjected to heating to be able to expand properly. In other words, it can be said that linear expansion occurs specifically in only one direction .

Characteristics of linear dilation

Among its main characteristics the following can be mentioned:

  • This process occurs only in those materials that have or are presented in solid state .
  • The increase in body size will always be proportional to the increase in temperature that has been applied.
  • It completely depends on the type of material to which it conforms to the body.
  • It may be that the dilation occurs in length and height , or that it occurs in length, height and width .
  • Although the dimension of the object increases, the pressure will always remain constant .
  • This process also involves the separation of the atoms that make up the expanded material.

Linear expansion coefficient

This type of coefficient is responsible for making measurements on the relative change that occurs in the length or volume of a body in solid state or of a liquid when it is inside a container in which it undergoes a change. temperature causing this expansion to occur. It is important to mention that, when heat is transmitted, all the energy that is stored in the bonds of the atoms undergoes a change.

In this way, each time the energy increases, the length of the bonds increases with it. The unit used to represent linear dilation measurements is (° C) -1. There is a formula that is used to be able to measure linear dilation, this is the following:

Where L represents the length and T the temperature . ΔT will be the variation of the temperature and after the thermal equilibrium is established next to the source that causes the heat, then T ‘= T + ΔT will be obtained. Below is a table with some materials and their respective linear expansion.

Material α (10-6 ° C-1)
Iron 12 ∙ 10-6 (° C) -1
Steel 12 ∙ 10-6 (° C) -1
Copper 17 ∙ 10-6 (° C) -1
Brass 18 ∙ 10-6 (° C) -1
Aluminum 23 ∙ 10-6 (° C) -1
Mercury 60.4 ∙ 10-6 (° C) -1
Lead 30 ∙ 10-6 (° C) -1
PVC 52 ∙ 10-6 (° C) -1
Gold 14 ∙ 10-6 (° C) -1
Oak 54 ∙ 10-6 (° C) -1


Knowing the linear dilation of bodies is important because this is an aspect that influences many fields of daily life . It is important, for example, in pipelines that carry hot water, which allows to increase the useful life of the materials used. Materials such as construction rods can be expanded using linear expansion which is important as these materials are part of the development.

Examples of linear dilation

Some examples that can be observed in which linear dilation is present are the following:

  • On the train tracks which are subject to extremely high temperatures as the machine cars go by. This produces a significant agitation in all the atoms of the structure which makes the railroad able to expand.
  • Another clear example that is easier to observe on a daily basis is when a bar or a piece of some material is taken and subjected to high temperatures, this increase will cause the dimensions to be altered by increasing the length .
  • Materials such as pipes , parquet floors , and metal rods used in construction can be mentioned .

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