Science 9: Characteristics of Electricity (Lessons 5-8)

Comprehensive vocabulary flashcards covering basic circuits, series and parallel rules, electrical quantities (voltage, current, resistance), Ohm's law, safety devices, and electrochemical cells.

Electric Circuit

A complete closed pathway in which electrons and electric current can flow, consisting minimally of an energy source, a conductor, and an electrical load.

Source (Circuit Component)

A circuit component, such as a battery or cell, that provides energy and a supply of electrons to an electrical circuit.

Conductor

A conducting wire or material that provides a pathway allowing electric charge to flow freely through a circuit.

Switch

A control device in a circuit that turns the flow of current on or off by closing or opening the loop.

Load

A device in an electrical circuit that converts electrical energy into another form of energy, such as light or heat.

Circuit Diagram

A standardized schematic model using specialized symbols that engineers and designers use to design and analyze an electrical circuit.

Series Circuit

A circuit configuration with only one pathway for electrons to flow, where components are connected one after another, current is equal throughout, and removing one load stops the entire circuit.

Parallel Circuit

A circuit configuration where devices are arranged along multiple paths, allowing electrons more than one complete route so an interruption in one branch does not stop current flow in the others.

Electric Current ($I$)

The measure of the rate of electric charge passing by a point in an electrical circuit within a given time interval, measured in amperes ($\text{A}$).

Direct Current (DC)

An electric current that flows continuously in only a single direction.

Alternating Current (AC)

An electric current that periodically reverses its direction by flowing back and forth, which is the type of power supplied through household wall sockets.

Ammeter

An electrical instrument connected in series with a device to measure the electric current flowing through it in amperes ($\text{A}$).

Voltage ($V$)

The difference in electrical energy between two locations (the electrical pressure or push that forces charges through a circuit), measured in volts ($\text{V}$).

Voltmeter

An electrical instrument connected in parallel across a component to measure the potential difference (voltage) across that device in volts ($\text{V}$).

Resistance ($R$)

The opposition or degree to which a substance resists the flow of electric current through it, measured in ohms ($\Omega$).

Resistor

A circuit component that offers resistance to the flow of electric charges, converting electrical energy into heat energy to reduce current in parts of a circuit.

Superconductor

A material that displays zero electrical resistance when cooled to near absolute zero ($-273\,^\circ\text{C}$), enabling electrons to travel completely without energy loss.

Ohm's Law

The physical relationship stating that voltage across a conductor is directly proportional to current and resistance, expressed by the formula $V = IR$.

Short Circuit

An unintended, low-resistance connection formed between two points in an electrical circuit that bypasses the normal load, resulting in excessive current flow and potentially dangerous heat.

Fuse

A safety device containing a thin metal strip designed to melt and permanently open the circuit when excessive current passes through it, requiring replacement once blown.

Circuit Breaker

A resettable electrical safety device containing a bimetallic strip that heats and bends to interrupt excessive current flow, which can be reset after cooling without needing replacement.

Three-Prong Plug

A safety plug where two prongs conduct working current to and from the source, and a third prong connects the chassis to ground to safely divert unwanted fault current during a short circuit.

Ground Fault Circuit Interrupter (GFCI)

A sensitive circuit-interrupting outlet device that detects unintended differences in current and immediately shuts off electrical power, specifically used where appliances could contact water.

Electric Motor

An electrical machine that converts electrical energy into mechanical energy.

Electric Generator

A mechanical device that converts mechanical energy into electrical energy by moving a conductor through a magnetic field to induce an electric current.

Electrochemical Cell

A package of chemicals consisting of two electrodes and an electrolyte that converts stored chemical energy into electrical energy.

Electrolyte

A liquid or paste substance containing chemicals that form ions, enabling the conduction of electric charge within an electrochemical cell.

Electrode

A solid conductor, typically a metal strip such as zinc or copper, that chemically reacts with the electrolyte in an electrochemical cell to release or accept electrons.

Dry Cell

An electrochemical cell that uses a moist chemical paste rather than a liquid electrolyte, making it completely sealed and functional in any position without leakage.

Wet Cell

An electrochemical cell that utilizes a liquid electrolyte solution, commonly used in car batteries because it is economical and easily recharged, despite the hazard of liquid spills.