Electricity

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Electricity

• Static and Dynamic
• Magnetism

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Electricity

• Electricity refers to all phenomena caused by
  electric charges (positive and negative)

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When is it positive? When is it negative?

• A negatively charged body has more electrons than
  protons
• A Positively charged body less electrons than
  protons

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Electric Charges

• Elementary electric charge is the charge of an
  electron or protons (1,602 x 10-19 C)
• C refers to Coulomb

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The BasicsForces of attraction and repulsion

1. Like electric charges repulse each other
2. Opposite electric charges attract each other
3. The force that pushes charges together or apart
   is called the electric force
4. The Law of conservation of charges states that
   no charge is created or destroyed only transferred

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How do we give charge?

• How a material reacts when given a charge will
  determine in which category they will be placed
• Conductors
• Insulators
• Semi-conductors

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Link to the periodic Table

• Which elements do you believe would be considered
  conductors?
• Which elements do you believe would be considered
  insulators?
• Which elements do you believe would be considered
  semi-conductors?

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Conductors

• Substances that allow the free flow of electrons
• Usually metals (from the periodic table) because
  they are willing to give up their valence
  electrons
• Can also be an electrolytic solution
• electrolyte is any substance containing free ions
  that make the substance electrically conductive

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What is an ion?

• An ion is an atom that as become electrically
  charged by losing or gaining one or more
  electrons

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Periodic Table and ions
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Insulator

• Substance that inhibits (prevents) the free flow
  of electrons, because they want to hold on to
  their valence electrons.
• Once charged, the charges will stay in a specific
  location
• Often non-metals as well as wood, plastic, glass,
  ceramics, rubber, silk and air

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Semi-conductors

• Substance in which the conductivity depends on
  the conditions
• Metalloids and carbon are examples of
  semi-conductors

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Electrical fields

• The electric field is the region in which the
  electric force of an object can act.

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Static Electricity

• All phenomena related to electric charges at rest
• Over time an electrically charged body can loose
  its charge gradually
• In other cases, an object can recover its neutral
  state quickly through an electrostatic discharge.

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Hey Look!!! A new carpet
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OOPS!!
Lump of Coal
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Charging an object

• By friction

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Charging an object

• By friction
• Start with two neutral objects
• When rubbing the two objects together, electrons
  from one object will be ripped off by the atoms
  of the second object
• End two objects with opposite charge

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• Tendency to have
• a negative charge
• Tendency to have
• a positive charge

• Plastic
• Gold
• Nickel, Copper
• Sulfur
• Wood, amber, resin
• Coton
• Paper
• Silk
• Lead
• Wool
• Glass

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Charging an object

• Conduction
• One charged object touches a neutral object
• The Charged object shares its charge with the
  neutral object
• We are left with two objects of the same charge

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Charging an object

• Induction
• One neutral, one charged
• Without touching the objects together, the
  charges in the neutral object will separate
• One charged, one partially charged

WEEEE!!!






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