Static electricity

• What is static electricity?

  Build-up of charge on insulating materials
• What causes sparks in static electricity?

  Discharge of built-up charge
• What do all materials contain that contributes to charge?

  Positive protons and negative electrons
• Why are most materials neutral overall?

  Positive and negative charges cancel each other out
• What happens when materials are rubbed together?

  Electrons are transferred from one to another
• What occurs in conducting materials when rubbed?

  Electrons flow back, no charge builds up
• What happens in insulating materials when rubbed?

  Electrons can't flow back, charge builds up
• What charge does a polythene rod acquire when rubbed with cloth?

  Negative static charge
• What charge does cloth acquire when rubbed with a polythene rod?

  Positive static charge
• 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 cloth?

  Electrons transfer from acetate to cloth
• What is the key point about static charge transfer?

  Only negative electrons are transferred
• What happens as an object gains more negative electrons?

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

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

  Electrons can jump across the gap
• What is a spark in terms of static electricity?

  Jumping of electrons across a gap
• Can charges build up on conductors?

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

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

  You may experience a small electric shock
• What is the result of a car discharging to the earth?

  A small spark through your body
• What are the key concepts of static electricity?

  • Build-up of charge on insulators
  • Charge cancellation in neutral materials
  • Electron transfer during friction
  • Potential difference and sparks
  • Charge accumulation on conductors
• What are the differences between conductors and insulators in static electricity?

  Conductors:

  • Electrons can flow back
  • No charge builds up

  
  

  Insulators:

  • Electrons cannot flow back
  • Charge builds up