Static electricity

• What is static electricity?

  Build-up of charge on insulating materials
• Why do most materials have an overall neutral charge?

  Positive protons and negative electrons cancel out
• What happens when two insulating materials are rubbed together?

  Electrons transfer from one to another
• What occurs in conducting materials when rubbed together?

  Electrons flow back, no charge builds up
• What is an example of an insulating material?

  Polythene rod
• What happens to the cloth and polythene rod during friction?

  Cloth loses electrons, becomes positive
• How does the transfer of electrons depend on materials?

  It varies based on specific materials involved
• What happens when an acetate rod is rubbed with a cloth?

  Acetate rod loses electrons, becomes positive
• What causes positive static charges on an object?

  Loss of negative electrons, not gain of protons
• What develops as an object gains more negative electrons?

  A potential difference between the object and earth
• What is the potential of earth objects?

  Always at zero volts
• What happens if the potential difference is large enough?

  Electrons can jump across the gap, causing a spark
• Can charges build up on conductors?

  Yes, but it's less common
• How can cars build up charge?

  Metal frame contacts wind, transferring electrons
• What happens when you touch a charged car?

  You may experience a small electric shock
• What is a spark in terms of static electricity?

  Jumping of electrons across a gap
• What are the key points about static electricity?

  • Build-up of charge on insulators
  • Charges cancel out in neutral materials
  • Rubbing causes electron transfer
  • Conductors allow electrons to flow back
  • Insulators retain charge after rubbing
  • Positive charge from lost electrons
  • Potential difference leads to sparks
• What is static electricity?

  Build-up of charge on insulating materials
• Why do most materials have an overall neutral charge?

  Positive protons and negative electrons cancel out
• What happens when insulating materials are rubbed together?

  Electrons are transferred, causing charge build-up
• What occurs in conducting materials when rubbed together?

  Electrons flow back, preventing charge build-up
• What happens to a polythene rod when rubbed with a cloth?

  It gains negative charge, cloth becomes positive
• How does the transfer of electrons depend on materials used?

  Specific materials determine the direction of transfer
• What is the result of an object losing electrons?

  It becomes positively charged
• What develops as an object gains more negative electrons?

  A potential difference between the object and earth
• What happens if the potential difference is large enough?

  Electrons can jump across the gap, causing a spark
• What can cause charge build-up on conductors?

  Contact with wind transferring electrons
• What might happen when you touch a charged car?

  You may experience an electric shock
• What are the key points about static electricity and charge transfer?

  • Static electricity is charge build-up on insulators.
  • Charges cancel out in neutral materials.
  • Rubbing insulators transfers electrons.
  • Conductors allow electrons to flow back.
  • Charge build-up can occur on conductors too.
• What is the process of charge transfer when rubbing materials?

  1. Rubbing causes friction.
  2. Electrons are transferred from one material to another.
  3. One material becomes positively charged, the other negatively charged.
  4. The direction of transfer depends on the materials involved.