Static Electricity

• Static electricity is caused by a build up of electric charges that are not free to move
• Electric shock

  Occurs when the built-up charges eventually move
• Spark

  Occurs when the built-up charges eventually move
• Build-up of static electricity

  1. Electrons move from one insulating material onto another when they are rubbed together

  2. One material becomes positively charged as it loses electrons

  3. The other material becomes negatively charged as it gains electrons
• Positive and negative charges attract each other (electrostatic attraction)
• Positive charges repel each other (electrostatic repulsion)
• As the potential difference between an object and the Earth increases


  The likelihood of a spark occurring increases
• Spark


  Electrons jump across the gap between a charged object and the Earth or an earthed conductor
• Lightning is an example of a very large spark caused by a potential difference between charged storm clouds and the Earth
• Electric field

  Created by electrically charged objects, the closer you get to the object the stronger the electric field
• Electric field lines


  • Always flow from positive to negative electrical charge
  • The more electric field lines in an area, the stronger the electric field
• Force on an object in an electric field

  Caused by the interaction of the electric field of the object and the electric field it has been placed in, can cause attraction or repulsion
• Production of sparks using electric fields

  1. High potential difference between a charged object and the Earth produces a strong electric field

  2. This electric field removes electrons from the air within the electric field, ionising the air

  3. The ionised air becomes an electrical conductor and a large current may flow through it, this current is the spark