PS.11 The student will investigate and understand basic principles of electricity and magnetism. Key concepts include
1. static electricity, current electricity, and circuits
2. relationship between a magnetic field and an electric current
3. electromagnets, motors, and generators and their uses
4. conductors, semiconductors, and insulators

Static electricity, Current electricity, and Circuits

• Several factors affect how much electricity can flow through a system.
• Resistance is a property of matter that affects the flow of electricity. Some substances have more resistance than others.

• Friction can cause electrons to be transferred from one object to another.
  • These static electrical charges can build up on an object and be discharged slowly or rapidly.
  • This is often called static electricity.
    
    

Electromagnets, Motors and Generators and their uses

• Electricity is related to magnetism.
• Magnetic fields can produce electrical current in conductors.
  • Electricity can produce a magnetic field and cause iron and steel objects to act like magnets.
  • Electromagnets are temporary magnets that lose their magnetism when the electric current is removed.
• Both a motor and a generator have magnets (or electromagnets) and a coil of wire that creates another magnetic field.
  • A generator is a device that converts mechanical energy into electrical energy.
  • Most of the electrical energy we use comes from generators.
  • Electric motors convert electrical energy into mechanical energy that is used to do work.
  • Examples of motors include those in many household appliances, such as blenders and washing machines.

Conductors, Semiconductors, Insulators

• A conductor is a material that transfers an electric current well.
• An insulator is material that does not transfer an electric current.
• A semiconductor is in-between a conductor and an insulator.
• The diode is a semiconductor device that acts like a one way valve to control the flow of electricity in electrical circuits.
  • Solar cells are made of semiconductor diodes that produce direct current (DC) when visiblelight, infrared light (IR), or ultraviolet (UV) energy strikes them.
  
  • Light emitting diodes (LED) emit visible light or infrared radiation when current passes through them.
  • An example is the transmitter in an infrared TV remote or the lighting course behind the screen in an LED TV or notebook computer screen.
• Transistors are semiconductor devices made from silicon, and other semiconductors.
  • They are used to amplify electrical signals (in stereos, radios, etc.) or to act like a light switch turning the flow of electricity on and off .