Difference Between Isotropic vs Anisotropic

Difference Between Isotropic vs Anisotropic

There are more substances in existence then we can count with 118 identified elements and a lot more yet to be discovered, according to scientists. As you may already know, they have varying properties and compositions. To make it easier to identify them, they were classified into various categories based on their qualities.

In this post, we will be discussing the difference between anisotropic and isotropic, two distinct categories of matter characterized by certain qualities. These two are the opposite of the other, but they both refer to their dependence or independence on the direction as it has to do with crystallography.

Definition of Isotropic

Isotropic is defined as the identical multi-directional properties of a material. Any material described in this manner simply has identical properties but in dissimilar directions. This word is originally Greek, formed by the combination of the terms “isos” and “tropos,” meaning “equal” and “way,” respectively. An object described as such is said to have the same material property in all directions.

The basis of this property is in the bonds of the atoms that make up the material. If the bonds are strong, it makes the object hard to break, and if not, it makes it easy to break. This, however, depends on what factor the object is subjected to. It could be conductivity, electrical resistance, absorptivity, and so on.

For an object that is described as multi-directional, the bonds are pretty much unorganized. Examples include glass and metal. These two have material properties in all directions, which are mostly unorganized.

One thing to keep in mind in the anisotropic vs isotropic comparison is that even if a material has anisotropic regions, the material as a whole can be isotropic if the anisotropic regions are randomly oriented so that can cancel each other out.

Definition of Anisotropic

Anisotropic is the property of a material which allows it to change or assume a different property in diverse directions. From the definitions of these two terms, one can say that the difference between isotropic and anisotropic can be seen in the directions of the properties exhibited by the materials.

The former has materials with identical properties exhibited in various directions, while the latter has different properties exhibited in unlike directions.

Materials classified under this category are also known as “triclinic” materials. They are characterized by direction-dependency and are made up of unsymmetrical crystalline structures. The atoms are concentrated and distributed uniquely with respect to varying directions.

A very good example that describes this concept is wood. When you look at the interior of a piece of wood, you can see that the lines go in the same direction, which is why it is hard to snap a piece of wood in between the lines while it is easier to snap it across the lines. This is why it is referred to as an unsymmetrical crystalline structure. Each surface reacts differently when subjected to the same condition.

Main Differences Between Isotropic vs Anisotropic

You can only learn so much from the definitions of these terms. There are other ways to distinguish these terms from the other judging by their uses, appearance, refractive index, the velocity of light, chemical bonding, and so on.

Basis of ComparisonIsotropicAnisotropic
DefinitionThe identical multi-directional properties of a materialThe tendency of a material to exhibit different properties in diverse directions
DirectionIndependentDependent
Makes use ofLensesPolarizers
Chemical bondingConsistentUncertain
Velocity of lightSame in all directionsVaries with direction
Physical propertyDark appearanceLight appearance
Double refractionNoYes
ExampleMetal, glass, diamonds, air, water, etc.Composite materials, wood, all crystals except cubic crystals, etc.

Difference Between Isotropic and Anisotropic: Conclusion

Understanding the isotropic vs anisotropic comparison is crucial in crystallography, which is a branch of science that deals with the manner of arrangement and the type of bonding that exists between atoms of different materials and properties.

From all that has been said so far, the latter can also be defined as the existence of dissimilar properties in various directions while the former is the existence of similar properties in the various axis.