Electric Charges and Currents

1
Electric Charges and Currents
2
Electric Charge

• 3 parts of an atom
• Proton ( )
• Neutron ( o )
• Electron ( - )
• Like charges repel
• Different charges attract

3
Electric Field

• An electric field extends outward through space
  around every charged particle
• It is strongest near the charged particle

4
Static Electricity

• Objects become charged when they gain or lose
  electrons
• Friction occurs when two objects are rubbed
  against each other
• Static electricity is the buildup of electric
  charges on an object

5
Conductors/Insulators

• Conductors permit electric charges to flow freely
• - examples metals, Earth
• Insulators do not allow electric charges to flow
  freely
• - examples rubber, glass, wood, plastic, air

6
Lightning

• Lightning forms when there is a discharge of
  static electricity
• Bolt travels from negative charges to positive
  charges
• Elect. Pot. Difference is the amount of work
  required to move a charge (Volts)

7
Batteries

• A battery is a device that produces electricity
  by converting chemical energy into electrical
  energy
• Batteries can be either dry cell or wet cell

8
Thermocouples

• A thermocouple is a device that produces
  electrical energy from heat energy
• Used in car engines, ovens, and gas furnaces

9
Electric Circuits

• A circuit provides a complete, closed pathway in
  which electricity can flow
• Two types (series/parallel)
• Our homes have parallel circuits - if one light
  goes out, the others stay on

10
Two Types of Circuits
11
Electrical Safety

• Houses are protected against fires by fuses and
  circuit breakers
• Know the 6 electric safety rules on pages 37-38