T2: static electricity

• protons are positive
• electrons are negative
• neutrons are neutral
• conducting materials = copper, aluminium, gold, silver
• insulating materials = glass, air, plastic, rubber, wood
• insulating materials can be charged by friction by rubbing with cloth = hold close to paper = rub again = hold near water
• how to get charge difference in materials = remove electrons via friction or electricity
• photocopier:

  • friction used on paper to remove electrons = areas positively charged
  • ink made negatively charged using electricity
  • attracted
• car painting:

  • car made negatively = electricity
  • paint is positive = electricity
  • attract
  • dangerous as sparks can ignite fuel
• electrostatic = eg. balloon

  • negatively charged balloon approached neutrally charged wall
  • repel negative charges, attract positive charges
• aircraft through air = friction = charged with static electricity

  • dangerous with refuelling as sparks could ignite fuel = earth the plane after landing to remove charge