Liquid Crystals

Not all material falls neatly into one of the above categories. Metalloids, for example, possess
properties that are intermediate between those of metallic and covalent solids. A more astounding
example is that of liquid crystals, a state of matter in between liquids and solids.

Most of the substances that can form liquid crystals are long, rodlike organic molecules. Above a
certain temperature, they behave like normal liquids, oriented randomly and moving relatively
freely among themselves. As they are cooled, they pass through several intermediate phases, each
of increasing order. In particular, these rodlike molecules tend to line up parallel to one another.
The precise orientation these molecules choose to line up in is affected by external electric and
magnetic fields. It is this property that makes liquid crystals useful in electronic displays such as
certain computer screens.

A CLOSER LOOK

Liquid  crystals    are a   state   of  matter  in  between liquids and solids. Above   a   certain

temperature,    they    behave  like    normal  liquids,    oriented    randomly    and moving  relatively

freely  among   themselves. As  they    are cooled, they    pass    through several intermediate    phases,

each    of  increasing  order.  In  particular, these   rod-like    molecules   tend    to  line    up  parallel    to

one another.    The precise orientation these   molecules   choose  to  line    up  in  is  affected    by

external    electric    and magnetic    fields. It  is  this    property    that    makes   liquid  crystals    useful  in

electronic  displays    such    as  certain computer    screens.