Electricity

• Portons never move
• Neutral object


  Always connect Charging by Induction no contact
• Charging by Induction


  1. Bringing a charged object close to a neutral object (without touching)

  2. Electrons of the neutral object shift in position

  3. Induced charge separation
• Charging by Induction


  • Can charge a neutral object temporarily or permanently
• Charged object is brought near a neutral object


  Electrons of the neutral object shift in position
• Charged object is positively charged


  Electrons in the neutral object move toward it
• Charged object is negatively charged


  Electrons in the neutral object move away from it
• Side of neutral object closest to charged object


  Attracted to the charged object, causing the neutral object to move toward it
• Charged object is moved away

  Electrons return to their original positions
• Permanently charging an object using induction

  1. Neutral object must be grounded

  2. Electrons can be permanently added or removed
• Electrons move from the neutral object to the ground


  Object loses electrons and becomes positively charged
• Electrons move from the ground to the neutral object


  Object gains electrons and becomes negatively charged
• Charging by conduction


  When two objects with different amounts of electric charge come in contact and electrons move from one object to the other
• How charging by conduction happens

  1. Electrons always move from the object with more electrons (more negatively charged) to the object with less electrons (less negatively charged)

  2. Transfer of electrons stops when both objects have the same amount of charge
• Neutral object and charged object


  • The neutral object takes on the charge of the charged object upon contact
• Negatively charged object with neutral object

  • Neutral object becomes negatively charged
• Positively charged object with neutral object


  • Neutral object becomes positively charged
• Charging by conduction example - metal leaf electroscope

  • When charged objects are brought near, electrons can move onto or out of the metal leaves
  • When the leaves have like charges, they repel and the leaves separate
  • When the leaves are neutral, they fall straight down
• Charging electroscope with a negatively charged object


  1. Before

  2. During

  3. After
• Charging electroscope with a positively charged object


  1. Before

  2. During

  3. After
• Grounding


  A process that removes excess charges (either positive or negative) on objects
• How grounding works


  For a positively charged object, electrons from the ground travel upwards until the object is neutralized

  For a negatively charged object, electrons from the object travel into the ground until the object is neutralized
• Electrostatic series


  • Human skin
  • Rabbit fur
  • Glass
  • Human hair
  • Nylon
  • Cat fur
  • Wool
  • Vinyl
  • Polyester
  • Wood
  • Amber

  Materials further down the list tend to gain electrons easier than those at the top of the list
• Rubbing two objects on the electrostatic series

  The object higher on the series will lose electrons and become positively charged, the object lower on the series will gain electrons and become negatively charged
• Conductors


  Materials that allow electrons to pass through easily (e.g. copper)

  Fair conductors (or semiconductors) allow electrons to pass through, just not as well as good conductors (e.g. graphite, human body)
• Insulators


  Materials where electrons cannot move freely from atom to atom (e.g. plastic)

  Electrons are bound more tightly to the atoms of the material
• You should never use an electrical appliance near water
• The items on the electrostatic series are mainly insulators
• Rubbing a balloon on your hair

  Electrons move from the hair to the balloon, making the balloon negatively charged and the hair positively charged. The opposite charges attract, causing the balloon to stick to the hair.
• Law of Electric Charges

  Opposites attract
• Pith ball electroscope and metal leaf electroscope


  • Move toward the object when detecting a charge
• Charge on objects


  • Positive
  • Negative
  • Neutral
• Charging methods


  1. Charging by friction

  2. Charging by conduction

  3. Charging by induction
• Electrostatic series


  • Polyester (negative)
  • Wool (neutral)
  • Silk (neutral)
  • Nylon (positive)
  • Acetate (positive)
  • Glass (positive)
• Neutral objects are attracted to charged objects
• Conductor


  Material that allows electric charge to flow through it easily
• Insulator


  Material that does not allow electric charge to flow through it easily
• Conductors and insulators


  • Silver (C)
  • Rubber (I)
  • Copper (C)
  • Tap water (C)
  • Diamond (I)
  • Wood (I)
  • Pure water (I)
  • Oil (I)
• Electricians wear rubber gloves when handling electric cables
• Handheld insulators were used in electrostatic experiments, not conductors