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 between them
• What is the effect of friction on insulating materials?

  It causes electrons to be rubbed off
• What happens to the material that loses electrons?

  It becomes positively charged
• What happens to the material that gains electrons?

  It becomes negatively charged
• How do conducting materials behave with charge?

  Electrons flow back, preventing charge build-up
• What is an example of an insulating material?

  Polythene rod
• What happens when an acetate rod is rubbed with a cloth?

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

  Only negative electrons are transferred
• 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
• 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
• Why might a car build up charge?

  Metal frame contacts the wind
• What happens when you touch a charged car?

  You may get an electric shock
• What is the result of a small spark from a car?

  Discharge to the earth through your body
• What are the key concepts of static electricity?

  • Build-up of charge on insulators
  • Charge transfer through friction
  • Positive charge from lost electrons
  • Negative charge from gained electrons
  • Potential difference leading to sparks