Electricity Vocabulary
• Negatively charged ion– Gains electrons
• Positively charged ion– Loses electrons
Charges
• Law of Electric Charges • Like charges repel, unlike charges attract
Electrical Forces
• Electrical forces depend on 2 things:– The quantity of the charge involved– How far apart the charges are (the distance
between the charges) closer farther apart
Friction
• Charging by rubbing together like walking across a carpet
Induction
• Neutral metal comb held near an object with a negative charge, comb becomes charged
• No touching!
Conduction
• Charging by touching
Types of Current
• Direct current• Battery
• Alternating current• School and home
Resistance
• Affected by– Thickness of a wire– Length of a wire– Temperature of a wire
Types of CircuitsA circuit is a complete path for electricity to flow
• Series– Flow in one path– When an element in the
path stops working, all elements stop
• Parallel– Flow is in more than one
path– When one element
stops working, the electricity can flow in other paths keeping the other elements working
– Most circuits in home/school are parallel
Ground Fault Circuit Interrupters
• Shuts down a circuit when it senses unequal current going into and out of the circuit
• Often in kitchens and bathrooms because there is water that presents a shock hazard
• Other types of safety devices: fuses, circuit breakers
Semiconductors
• Crystalline solid• Conducts electricity
only under certain circumstances
Integrated Circuit
• Thin slice of silicon• Solid state components• Used in computers, cell
phones, many electronics
Magnetic Force
• The force a magnet exerts on another magnet
• Iron or a similar metal• On moving charges
Interaction Between Magnetic Poles
• Like poles repel each other
• Opposite poles attract each other
• Law of Electric Charges
Direction of Magnetic Poles
• Starting from the left what magnetic poles are shown on the two bar magnets?
• north, south, north, south
Magnetosphere
• Area surrounding Earth that is influenced by Earth’s magnetic field
• Helps protect the earth from the sun’s radiation
• Causes the aurora borealis/australis
Magnetic Domain
• A region that has a large number of atoms
• Magnetic fields are lined up parallel to a magnet’s field
Permanent Magnet
• A ferromagnetic material that has domains that remain aligned for a long period of time
• Neodymium (Nd)• Iron (Fe), Cobalt (Co),
Nickel (Ni)
Other Vocabulary
• Static discharge– Pathway through which
charges can move suddenly
– lightning
• Ohm’s Law– I = V/R– If you increase the
resistance, the current decreases
– I and R are indirectly proportional
Units
• Voltage = volt (v)• Current = I (amps)• Resistance = R (ohms, Ω)• Power = P (watts)• Energy = kilowatt•hours (kw •h)• Time = t (hours, h)
• Calculating your electrical bill:
# of kw •h x price/ kw •h = what you owe
100 kw •h x $0.185/ kw•h= $18.50
Conductors and Insulators
• Conductor– Allows the flow of
electricity easily– metals
• Insulator– Opposite of a conductor– Does not allow the flow
of electricity easily– Glass, air, wood, rubber,
plastic
Magnetic Field
• Moving electric charges• Creates a magnetic field
Solenoid
• A coil of wire that is carrying a current • Also produces a magnetic field
Electric Motor
• Periodically changing the direction of current in the electromagnet can cause the axle to spin because the magnetic field reverses direction
Generator
• A device that changes mechanical energy to electrical energy by rotating a coil of wire through a magnetic field
Fossil Fuels: Electricity Generation
• Heat from burning fuel creates steam that spins a turbine
Electromagnets
• Ferromagnetic core• Solenoid• Power source
Increasing the Strength of an Electromagnet
• More coils of the same length of wire• A thicker core with the same length of wire• Greater current with the same length of wire• A combination of all of the above
Grounding
• Transfer of excess charge through a conductor to the Earth
• Lightning rod
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