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