Static electricity

• Insulating materials


  Materials that can become (statically) electrically charged when rubbed together
• What can happen when insulating materials are rubbed together

  They can become (statically) electrically charged
• Why insulators become electrically charged when rubbed together

  • Electrons are rubbed from one material onto the other
  • The material gaining electrons becomes negatively charged
  • The material losing electrons becomes equally positively charged
• Two electrically charged objects are brought close together


  They exert a force on each other
• Two identically charged objects are brought close together

  They exert a repulsive force on each other and repel
• Two oppositely charged objects are brought close together


  They exert an attractive force on each other and attract
• Non-contact force


  The repulsive or attractive force acting between two electrically charged objects
• Electric field


  A region in which a charged object will experience a non-contact electrical force
• Electric fields can be found surrounding any charged object
• Electric field around a charged particle

  • Strongest closest to the object
  • Decreases in strength as you move away from the object
• Two charged objects are moved closer together

  The force between them becomes stronger as the separation reduces
• Precaution to prevent the build up of static charge in situations where sparks are unwanted


  Any surfaces that are rubbing against each other should be earthed to allow the charge to flow off the materials