Cambridge HSC key terms

The set of physiological processes that keep an organism's internal conditions, such as temperature, pH and blood glucose, within a narrow stable range despite changes in the external environment.

A protein, or occasionally RNA, molecule that speeds up a specific biochemical reaction by lowering its activation energy without being consumed; its activity depends on temperature, pH and substrate concentration.

The calculation of quantities of reactants and products in a chemical reaction using the mole ratios shown in a balanced equation, allowing prediction of masses, volumes or concentrations.

A rule stating that when a system at equilibrium is disturbed by a change in concentration, pressure or temperature, the system shifts in the direction that partially opposes the change.

The time required for half the nuclei in a radioactive sample, or half a reactant's concentration, to decay or be consumed; it is constant for a given first-order process.

The generation of an electromotive force in a conductor when the magnetic flux through it changes, as described by Faraday's law; the operating principle behind generators and transformers.

The process by which individuals with inherited traits that improve survival and reproduction in a given environment leave more offspring, so those traits become more common over generations.

The consistency of a measurement or source: repeated trials or independent readings give similar results, and the method can be trusted to produce the same outcome under the same conditions.

The extent to which a test, measurement or experimental design actually measures or demonstrates what it claims to, rather than being distorted by confounding variables or measurement error.

The variety of language a speaker or writer selects for a particular audience, purpose and situation, ranging from formal to informal and shaped by word choice, grammar and tone.

A verb form used to express wishes, doubt, hypothetical situations or commands rather than statements of fact; in French it commonly follows expressions such as 'il faut que'.

The practice of alternating between two or more languages or dialects within a conversation or text, often signalling group identity, emphasis or a change of topic.

A single sentence, usually near the start of an essay, that states the central argument or interpretation the writer will develop and support with evidence.

The instantaneous rate at which a function's output changes with respect to its input, interpreted geometrically as the gradient of the tangent to the curve at a point.

The probability that an event occurs given that another event is known to have occurred, written P(A|B) and calculated as the probability of both events divided by the probability of the condition.

A measure of how spread out a set of data is, equal to the square root of the variance; a small value indicates that scores cluster closely around the mean.

A proof technique for statements about whole numbers: show the statement holds for a base case, then prove that whenever it holds for one value it must hold for the next.

The exponent to which a fixed base must be raised to produce a given number; logarithms convert multiplication into addition and help solve equations where the unknown is an exponent.

A quantity possessing both magnitude and direction, represented as a directed arrow or an ordered list of components and added using the triangle or parallelogram rules.

The value of the next best alternative given up when a choice is made, including not only money but also the time and other resources forgone.

A measure of how strongly quantity demanded responds to a change in price, calculated as the percentage change in quantity demanded divided by the percentage change in price.

The level of sales at which total revenue equals total costs, so the business makes neither profit nor loss; it is usually expressed in units sold or sales dollars.

An accounting method that records revenue when it is earned and expenses when they are incurred, regardless of when cash actually changes hands between the parties.

The situation in which a country or firm can produce a good at a lower opportunity cost than another producer, forming the basis for mutually beneficial specialisation and trade.

A financial statement listing a business's assets, liabilities and owner's equity at one point in time, reflecting the accounting equation that assets equal liabilities plus equity.

The study of how history has been written, including the changing interpretations, methods and assumptions of historians and the debates between different schools of thought.

Evidence created at the time of the event being studied, such as letters, diaries, photographs, official records or artefacts, produced by someone with direct involvement.

Development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs, balancing economic, social and environmental goals.

The hierarchical arrangement of groups in a society according to wealth, status or power, producing unequal access to resources and unequal life chances.

The supreme authority of a state to govern itself and make laws within its territory without external interference; the term is also used in claims for Indigenous self-determination.

The growing interconnection of economies, cultures and societies worldwide through trade, investment, migration, communication technology and the movement of ideas and people.

A finite, unambiguous sequence of steps that takes an input and produces a desired output, able to be carried out mechanically and, ideally, efficiently.

An early working model of a designed product, built to test function, materials or user experience before full-scale production and typically refined through repeated iteration.

In computing, the process of hiding unnecessary detail behind a simpler interface or model so that a problem can be handled at a manageable level of complexity.

A systematic process of identifying hazards in a task or workplace, judging the likelihood and severity of resulting harm, and deciding on controls to reduce that risk.

The quality of a sound that distinguishes instruments or voices sounding the same pitch and loudness, determined by harmonic content and by the sound's attack and decay.

The planned arrangement and movement of performers on stage, including their positions, entrances and crossings, used to shape focus and communicate relationships to the audience.

A performance created collaboratively by an ensemble rather than from a published script, often beginning with improvisation, images or research and refined through rehearsal.