Grade 9 Science Unit 3 – Electricity

This set of vocabulary flashcards covers introductory concepts of electricity, including static and current electricity, energy sources, electrical measurements, and circuit types based on Grade 9 Science notes.

Electricity

The build-up of negative charges, which are called electrons.

Static Electricity

A naturally occurring form of electricity consisting of the build-up of non-moving extra electrons inside the body of an object.

Neutral Object

An object that has an equal number of positive protons and negative electrons.

Electric Discharge

The process where excess negative electrons jump from one object to another to balance charges, appearing as small blue-white sparks.

Cloud-to-Ground Lightning

A type of lightning where a negative cloud sends excess electrons to the neutral ground (sink).

Ground-to-Cloud Lightning

A type of lightning where the ground sends extra electrons to a positive cloud.

Charging

Causing an object to become either positive or negative, often through rubbing materials together.

Triboelectric Series

A list that ranks materials by their likelihood of giving or taking excess electrons when rubbed against other materials.

Law of Electric Charges

The rule stating that objects with opposite charge will attract each other and objects with like charge will repel.

Current Electricity

The movement or flow of negative electrons through a material along a path from a source to a destination.

Generator

A device that converts mechanical energy (turning, spinning, moving) into electrical energy.

Hydroelectricity

A variation on generators that uses moving water to turn a turbine, which then turns a generator to produce electricity.

Solar Energy

The process of converting light energy into electrical energy when photons from the sun strike a solar panel.

Nuclear Energy

The use of nuclear material to superheat water into steam, which shoots through pipes to spin turbines and convert kinetic energy into electrical energy.

Thermocouple

A device consisting of two wires tightly wound around each other that converts heat energy into electricity.

Piezoelectric Effect

The conversion of mechanical pressure (squeezing) into electrical energy, occurring when certain crystals like quartz are squeezed or struck.

Current ($I$)

A measure of the speed of electrons in a wire or how many electrons pass a given point in a specific amount of time, measured in Amperes ($A$).

Voltage ($V$)

The difference between the negative and positive side of a circuit, known as electric potential difference, measured in Volts ($V$).

Resistance ($R$)

The amount a wire slows electrons down due to friction and collisions between moving electrons and the particles of the wire, measured in Ohms ($\Omega$).

Resistivity ($\rho$)

The inherent level of resistance a specific metal has; for example, silver is more conductive than gold.

Resistance Equation

The formula used to calculate resistance based on wire properties: R = rac{ ho imes L}{A}.

Ohm’s Law

An equation relating voltage, current, and resistance: $V = I imes R$.

Circuit

An unbroken pathway that electricity follows in a loop.

Series Circuit

A circuit consisting of a single loop with only one path to follow and no branches.

Parallel Circuit

A circuit loop with multiple paths and branches, allowing other branches to work if one wire breaks.

Power ($P$)

A measure of how much energy a device uses per second, measured in Watts ($W$).

Watt ($W$)

The unit of measurement for power, representing one Joule per second ($1J/s$).

Power Equation

The formula used to calculate power based on work and time: P = rac{W}{t}.