  Liquid crystals are the prototype of the so-called soft condensed matter. In
simple terms they are "structured liquids" that historically have received a
lot of interest because they help to generate new concepts and knowledge in
Physics, and possess important electro--optical applications, e. g., in
displays of mobile computers and telephones. More recently, it has been
discovered that liquid crystals could be applied in fabrication of
metamaterials and in biomedicine where they are potentially useful for tissue
identification, controlled drug delivery and detection of bacteria and viruses.
However, in Mexico, liquid crystals courses are included only in a few
undergraduate programs on Physics being elective in most of the cases.
Therefore, literature for teaching about liquid crystals in Spanish is scarce.
In this paper we will discuss about elementary Physics of liquid crystals and
the mathematical tools that permit to analyze them. We will explain, mainly,
how to analytically characterize the symmetry and order of static uniaxial
nematic liquid crystals, the most simple of all liquid crystal phases. We will
conduct this explanation in basic terms, suitable for science and engineering
students at intermediate undergraduate level, with knowledge about linear
algebra and vector calculus, willing to approach for the first time to this
subject. Our goal is to support the Latin American scientific community in
preparing human resources in this field. The article is written in Spanish to
contribute to the establishment and communication of concepts that only exist
in other languages in the specialized literature.
