Stage 5 Year 9 Science Examination Review

Comprehensive vocabulary flashcards covering the core concepts of Working Scientifically, Energy, Materials, and Disease for the Year 9 Science Final Examination.

Independent Variable

The variable that is intentionally changed or manipulated by the investigator in an experiment.

Dependent Variable

The variable that is observed and measured to assess the effect of changes made to the independent variable.

Controlled Variable

A variable that is kept constant throughout an investigation to ensure a fair and valid test.

Risk Assessment

A systematic process of identifying potential hazards in an investigation, assessing their risks, and implementing control measures to reduce harm.

Interpolation

The process of estimating an unknown data value located between known data points on a graph.

Extrapolation

The process of estimating an unknown data value beyond the range of recorded data points by extending the existing trend.

Experimental Validity

The extent to which an experiment accurately tests what it intends to test, ensuring all variables are controlled except the independent variable.

Experimental Reliability

The consistency and repeatability of experimental results obtained across multiple trials under the same conditions.

Experimental Accuracy

How close a measured experimental value is to the true or accepted standard value.

Law of Conservation of Energy

The principle stating that energy cannot be created or destroyed, only transferred between objects or transformed from one type to another.

Energy Efficiency

The percentage or proportion of total input energy that is successfully converted into useful output energy.

Ohm's Law

The law stating that the electric current through a conductor is proportional to voltage and inversely proportional to resistance, expressed as $V = I \times R$.

Series Circuit

An electrical circuit in which components are arranged along a single continuous pathway, sharing the same current throughout.

Parallel Circuit

An electrical circuit where components are connected across multiple separate branches, providing multiple pathways for current to flow.

Valency

A measure of an atom's combining power, determined by the number of electrons it must gain, lose, or share to achieve a stable noble gas configuration.

Ionic Bonding

The electrostatic attraction between oppositely charged ions formed when atoms transfer one or more valence electrons.

Covalent Bonding

A chemical bond formed when two non-metal atoms share one or more pairs of electrons to achieve stable outer shells.

Metallic Bonding

The electrostatic attraction between positively charged metal cations arranged in a lattice and a sea of delocalized electrons.

Cation

A positively charged ion formed when a neutral atom loses one or more electrons.

Anion

A negatively charged ion formed when a neutral atom gains one or more electrons.

Diatomic Molecule

A molecule consisting of exactly two atoms bonded together, such as $O_2$, $N_2$, or $H_2$.

Alkanes

A family of saturated hydrocarbons containing only carbon-to-carbon single bonds, ranging from methane ($CH_4$ or $C_1$) to octane ($C_8H_{18}$ or $C_8$).

Complete Combustion

A reaction occurring in excess oxygen that fully oxidizes hydrocarbons into carbon dioxide ($CO_2$) and water ($H_2O$).

Incomplete Combustion

A reaction occurring in a limited supply of oxygen, producing water along with toxic carbon monoxide ($CO$) and particulate carbon soot ($C$).

Bioaccumulation

The gradual buildup of non-biodegradable pollutants, such as microplastics or heavy metals, within the tissues of an organism over time.

Homeostasis

The process by which organisms maintain a stable, coordinated internal environment despite changes in external conditions.

Feedback Loop

A physiological control mechanism that monitors a variable, detects deviations from a set point, and triggers an effector response to restore equilibrium.

Pathogen

A disease-causing biological agent, such as a bacterium, virus, fungus, or parasite.

Infectious Disease

A disorder caused by pathogenic microorganisms that can be spread directly or indirectly between organisms.

Non-Infectious Disease

A medical condition not caused by pathogens and incapable of spreading between individuals, typically arising from genetic, lifestyle, or environmental factors.

Endemic

A disease or condition that is constantly present and maintained at a baseline level within a specific geographic area or population.

Epidemic

A widespread occurrence of an infectious disease that spreads rapidly and affects an unusually large number of individuals in a specific population or region.

Pandemic

An outbreak of an infectious disease that spreads across multiple countries, continents, or worldwide.

Vaccination

The biological preparation of weakened, dead, or component antigens introduced to stimulate an immune response and provide active immunity.

Antibody

A specialized protective protein produced by the immune system in response to an antigen that binds to and neutralizes specific pathogens.