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Electricity & Magnetism Notes
Static, Currents, Circuits
Magnetic Fields & Electro Magnets
Motors & Generators
 Atoms
o Have neutrons, protons and electrons
o Protons are ___________ charged
o Electrons are ____________ charged
 Electrons
o Located on the outer edges of atoms….they can be _________.
o A concentration of electrons in an atom creates a net ___________ charge
o If electrons are ___________ away, the atom become ________________ charged
 The world is filled with _____________ ______________.
 What is this electrical potential called?
o __________ _____________
 Static Electricity
o The _____________ of an electric charge on the surface of an object
o The charge builds up but _________ ______ ___________.
o Static electricity is ___________energy. It does not move. It is ___________.
 Static Discharge
o Occurs when there is a loss of static electricity due to three possible things:
 __________ – rubbing
 Conduction – _________ contact
 _____________– through an electrical field
 Electricity that moves..
o _____________: The flow of electrons from one place to another
o Measured in amperes (amps)
o ___________ Energy
 How do we control currents?
o With __________
o Circuit: is a ________ for the flow of ________. We use _______.
 There are 2 types of currents:
o _________ ________ (DC) – electrons flow in the ______ direction in a wire.
o ___________ ________ (AC) – electrons flow in __________ directions in a wire.
o http://www.youtube.com/watch?v=HqMqdFNWX4s#t=237
 There are 2 types of circuits:
o _________ Circuit: components are lined up along _____ path.
It the circuit is broken, all components turn off.
o _________ Circuit: there are _________ branching paths to the components.
If the circuit is broken at any one branch,
only the components on that branch will turn off.
Conductors vs. Insulators
 Conductors – material through which electric currents flows _________.
o Examples: metal and water
 __________ – materials through which electric current cannot move easily.
o Examples: Styrofoam, rubber, plastic and paper
 What is resistance?
o The ____________ ___ _______ of an electric current, producing heat.
o The greater resistance, the less current get through.
o Good conductors have low resistance.
o Measured in ________.
 What influences resistance?
o Material of wire (aluminum and copper have low resistance)
o ____________ (the thicker the wire, the lower the resistance)
o Length ( the shorter the wire, the lower the resistance)
o _____________(the lower the temperature, the lower the resistance)
 What is _________?
o The measure of energy given to the charge flowing in a circuit.
o The greater the voltage, the greater the force or “___________” that drives the
charge through the circuit.
 Difference between Volts and Amps?
o Example…..You could say that…
 Amps measure how much water comes out of a hose.
 Volts measure how hard the water comes out of the hose.
 Ohm’s Law
o Ohms = Volts/Amps
 What is an electromagnet?
o Electromagnetic – a magnet made from a current bearing coil of wire wrapped
around an iron or steel core.
o http://www.youtube.com/watch?v=iSuSWi7YThA
 What is a generator?
o A machine that changes mechanical energy to electrical energy.
o Usually moving magnets to create currents in coils of wire.
o http://www.youtube.com/watch?v=NqdOyxJZj0U#aid=P89ox56462A
 What is a motor?
o A device that changes electrical energy to mechanical energy that can do work.