What is Electricity?

Overview:

Electricity is all around us–powering technology like our cell phones, computers, lights, soldering irons, and air conditioners. It’s tough to escape it in our modern world. Even when you try to escape electricity, it’s still at work throughout nature, from the lightning in a thunderstorm to the synapses inside our body. But what exactly is electricity?

Definition

Electricity is simply put the movement or flow of electrons from one atom to another.

Going Atomic

To understand what electricity really is, we must go down to the very basic building block of matter ----- down to the atomic level.

Here's the Bohr's Atomic Model to illustrate the fundamental components of an atom.

An atom has three basic particles namely the electron, proton and neutron.

Electron - is negatively charged particle ( - )

Proton - is positively charged particle ( + )

Neutron - has no charged

Electron Flow

"What makes an electric charge (electron) move?"

You know that work has to be done to lift an object because the Earth's gravitational field is pulling the object down.

Gravity acting on the apple causing it to fall to the ground.

In a similar way, work must be done to move a charged particle to one point to another. The amount of work required to move a charge between to points or the work per unit of charge is called the 'electric potential difference' between the two points. To move charges we need a device that can do work. Such devices include: batteries and generators.  
                              

VOLTAGE - unit of potential difference between two points.

"But how do electrons flow?"

Electrons DO NOT move along a wire like cars on a highway. Actually, Any conductor (thing that electricity can go through) is made of atoms. Each atom has electrons in it. If you put new electrons in a conductor, they will join atoms, and each atom will deliver an electron to the next atom. This next atom takes in the electron and sends out another one on the other side. The movement or flow of atom is also known as electric current.

Electrons jumping from one atom to another

Ohm's Law

One of the most important and basic laws of electrical circuits is Ohm's law which states that the current passing through a conductor is proportional to the voltage over the resistance. 

Equation 

Ohm's law may sound a bit confusing when written in words, but it can be described by the simple formula:

where I = current in Ampere, V = voltage in Volts, and R = resistance in Ohms

This same formula can be also be written in order to calculate for the voltage or the resistance:

Sample Problem

If there are 10 Volts across a 5 Ohm resistor, what is the current?

 Solution: I = V/R
                 I = 10/5 = 2A