Natural Sciences Grade 8 Review: Chemical Reactions, Electricity, and Magnetism

Vocabulary flashcards covering chemical reactions, static electricity, electric circuits, and the effects of electrical current based on the provided Grade 8 natural science lecture transcripts.

Reactants

Substances on the left side of a chemical equation whose existing bonds are broken during a reaction.

Products

Substances on the right side of a chemical equation formed when new bonds are created, having different properties from the reactants.

Chemical Reaction

A process where existing bonds are broken and new bonds are formed to create products, where atoms are rearranged rather than lost or gained.

Fermentation

A chemical reaction occurring when yeast mixes with sugar, feeding on the sugar and converting it into alcohol.

Friction

The action of one surface or object rubbing against another, causing electrons to be transferred between the atoms of two materials.

Attraction

The tendency of particles with opposite electric charges to move towards each other.

Repulsion

The tendency of particles with the same electric charge to move away from each other.

Static Electricity

The build-up of electric charges on the surface of a non-conductor where charges do not move.

Non-conductor

Materials that do not allow electric charges to flow through them.

Static Electric Spark

A flash of light caused by the electric discharge of static electricity.

Electric Discharge

The flow of electric charge through a solid, liquid, or gas.

Positively Charged Atom

An atom that has lost electrons, resulting in having more protons than electrons.

Negatively Charged Atom

An atom that has gained electrons, resulting in having more electrons than protons.

Current Electricity

The flow of moving charge, usually carried by moving electrons in a wire.

Electric Circuit

A path in which charges continually move through a complete loop, returning to their original position and cycling through again.

Open Circuit

A circuit with gaps or spaces where the switch is not closed, preventing electric current from flowing.

Closed Circuit

A circuit with no gaps or spaces, allowing electric current to flow continuously.

Series Connection

A circuit arrangement where there is only one path for the electric current to flow through.

Parallel Connection

A circuit arrangement where there is more than one path for the electric current to flow through.

Total Resistance in Series Formula

The formula used to calculate total resistance in a series circuit: $R_T = R_1 + R_2 + R_3 + \dots$

Total Resistance in Parallel Formula

The formula used to calculate total resistance in a parallel circuit: $\frac{1}{R_{\text{TOTAL}}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3}$

Series-Parallel Resistance Formula

The equation used to find total resistance in a combined circuit: $R_{\text{tot}} = R_s + R_p$

Electric Current

The rate of flow of electrical charge through a circuit.

Potential Difference

The amount of energy needed to move one unit charge of electricity from one point to another across two points.

Resistance Formula

The relationship defined as $\text{Resistance of the object} = \frac{\text{Potential difference across its ends}}{\text{Current flowing through it}}$

Nichrome

A high-resistance material used to make coils of wires for heating elements in heating appliances.

Electromagnet

A setup consisting of an iron rod inside a coil of wire that gains an increased magnetic field when current is switched on and loses its magnetism when switched off.

Electrolytes

Liquids, such as salt water, vinegar, and copper sulphate solution, that allow electricity to pass through them.

Electrolysis

The chemical decomposition of an electrolyte caused by an electrical current.

Electrodes

Two wires or plates through which electric current enters and leaves an electrolyte.

Electroplating

An application of electrolysis where the flow of electric current causes a thin layer of metal to be deposited on an object.