Earlier we covered electrons moving from atom to atom. Metallic bonding forms copper. The bond is made when many metal atoms share their collected valence electrons. The valence electrons are not attached to any specific atom, so they move around freely.
Now to get these electrons moving in one direction and being of more use, they just need a push. This is by applying an electromotive force (emf), also known as voltage.
Voltage can be compared to the pressure water is forced out of your kitchen faucet. It would be the water pressure that caused the water to flow.
When you measure voltage, you measure the potential difference between two points in a circuit. It’s important to remember this because you may measure 0 volts and take a good shock if you touch that wire.
In Ohm’s Law, voltage is represented by “E.”