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 Circuits A 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 = kilowatthours (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/ kwh = $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