Electric Fields

Electric charges create an electric field

An electric field is created around any electrically charged object
The closer to the object you get, the stronger the field is
You can show an electric field around an object using field lines. For example, you can draw the field lines for an isolated, charged sphere:
Electric field lines go from positive to negative
They’re always at a right angle to the surface
The closer together the line, the stronger the field is

When a charged object is placed in the electric field of another object, it feels a force
This force causes the attraction or repulsion
The force is caused by the electric fields of each charged object interacting with each other
The force on an object is linked to the strength of the electric field it is in
As you increase the distance between the charged objects, the strength of the field decreases and the force between them gets smaller

Sparks are caused when there is a high enough potential difference between a charged object and the earth
A high potential difference causes a strong electric field between the charged object and the earthed object
The strong electric field causes electrons in the air particles to be removed
Air is normally an insulator, but when it is ionised it is much more conductive, so a current can flow through it. This is the spark