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Electricity Study Guide
Test Date: Monday, May 23rd
□ Electricity: The flow of electrons from one atom to another.
□ Static Electricity: It is created by rubbing objects together. During this process,
electrons are rubbed loose from some atoms creating a positive charge, while other atoms
gain electrons, creating a negative charge. Opposites attract--positive and negative
charges attract each other creating static cling. When objects (such as your finger) are
charged and then touch another object such as a doorknob, electrons jump to the door and
you feel a zap!
□ Circuit: The round trip path of electricity from its source and back to its source.
□ Closed circuit: A complete electrical path.
□ Open circuit: An electrical path with an opening that electricity can’t get past, cutting
off power to the outlet. An open circuit occurs when a wire is cut, a filament is broken (see
below), a fuse melts (see below) a switch is turned off, etc.
□ Short circuit: Two paths cross, creating a new path short of the destination. Power
never makes it to the destination (such as a lightbulb).
□ Switch: A device that opens/closes the circuit.
□ Filament: A fine wire stretched between two wires of a light bulb (part of the circuit).
The resistance of the fine wire to electrical flow causes electrons to pile up on the wire,
vibrate, get hot, and glow.
□ Fuse: A strip of metal that easily melts if the circuit gets too hot, opening the circuit
and cutting off the power supply. A safeguard.
□ Conductor: A material that makes a good path for electricity. Metal is the best
conductor. Copper is used in electrical wiring.
□ Insulator: A material that makes a poor path for electricity.
□ Electromagnet: Created when an electric current passes through a coil of wire. You can
make a simple electromagnet by wrapping a wire 9 or more times around a nail, then
connecting both ends of the wire to both ends of a battery. The flow of electrons through
the coil creates a magnetic field. Common uses—doorbells, loud speakers, junkyard crane.
□ Electrical safety: Remember that metal, water, and humans are very good conductors of
electricity. With that in mind, study the following rules:
-Never plug in a hair dryer, radio, television, or other electrical device near a sink,
tub or pool full of water.
-Never put a knife, screw driver, or really any device inside an electrical outlet.
-Never put a knife inside a toaster that is plugged in.
-Never try to take apart or fix an electrical appliance while it is plugged in.
-Never climb a tree that has a power line running through it. Also stay away from
the power line that connects to your house. Stay away from all
power lines.
-If a storm causes a power line to break, DO NOT TOUCH IT!
-Watch for “High Voltage” signs on buildings or walls. STAY OUT!
□ Michael Faraday: A scientist of the 1800’s who made the first generator which made
electricity easier and cheaper to obtain.
Simple Circuit
Simple Electromagnet