What is Electricity?
The word
"electricity" can be used to mean an electrical charge that does not
move (static electricity) or an electric charge that moves (current electricity)
or a form of energy (electrical energy).
All of these depend on what is
happening to the electrons in a material.
All materials are made up of
atoms. Every atom consists of a nucleus containing a number of positively
charged protons around which an equal number of negatively charged electrons
move. The nucleus also contains neutrons, which do not have any electrical
charge. The number of electrons in each atom of the material largely determines
a material's physical, chemical and electrical properties.
The atoms in some materials
have "free" electrons that are loosely bound to their nuclei. A free
electron can easily be induced to leave its atom and move about in random
directions in the spaces between the atoms. When wandering electron encounters
an atom, the electron could attach itself to the atom and could force another
electron to leave that atom. Electricity passes easily through these materials
which are called conductors.
In other materials, most of the
electrons are firmly bound to the nucleus and hence there are few
"free" electrons. Electricity does not easily pass through these
materials which are called non-conductors or insulators. |