An electric current is the rate of flow of electric charge past a point:2:622 or region.:614 An electric current is said to exist when there is a net flow of electric charge through a region.:832 In electric circuits this charge is often carried by electrons moving through a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionized gas (plasma). The SI unit of electric current is the ampere , which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit:15 Electric current is measured using a device called an ammeter.
When a bunch of electrons congregate in one place, their combined charges build up to a certain level of electric potential energy in that object. For example, when I rub this rubber balloon on my wool scarf, it causes a bunch of the electrons from the scarf to jump over on the balloon. Now the balloon is negatively charged, because it has a surplus of negatively charged electrons, and the scarf is positively charged, because it has a shortage of electrons.
Electricity occurs when electrons accumulate in or flow through the atoms that make up an object. And different types of materials, which are composed of different combinations of atoms, may allow those little electrons to move about more or less freely from atom to atom. Conductivity: The term conductivity describes how easily electrons are able to move around within certain materials, and it's determined by the structure of atoms in the material and how they're connected to each other.
All objects are made of tiny little building blocks called atoms which are way too small to see and each of those atoms consists of three types of even tinier little particles called protons, neutrons and electrons. Protons and electrons are particles which have equal and opposite electrical charges. We say that protons are positively charged and that electrons are negatively charged. The neutrons don't have any electrical charge so we call them neutral. The amount of charge in an object can be measured using a unit called coulombs which is abbreviated with a capital letter C.