Glossary term



A unit of electric current equal to a flow of one coulomb per second.

black body

An imaginary object that perfectly absorbs radiation (and also a perfect emitter) at all wavelengths.


The intrinsic electrical nature of a body. May be positive or negative.

classical physics

Physics as it was understood before the advent of quantum physics and relativity. The term is generally applied to the rules of physics that were established before the end of the 19th century.


An interaction, usually involving contact, between two or more bodies.


A judgement based on evidence.

controlled variable

A variable that is kept constant (or changed in constant ways) during an investigation.

dependent variable

A variable that changes in response to changes to the independent variable in an investigation.

digital technologies

Systems that handle digital data, including hardware and software, for specific purposes.


Having opposite electric charge at opposite ends of a molecule or body.


Changing over time, eg moving.


The property of a body that enables it to regain its original shape following the removal of a force that deformed it.

elastic collision

A collision in which the total kinetic energy of the colliding bodies after collision is equal to their total kinetic energy before collision.

electric current

The flow of electric charge, usually through a conductor or resistor. The term may refer to the flow of charged particles through a vacuum. In the context of current, charge may be electrons, ions or positive holes (in a semiconductor).

electric field

A region in which a stationary electric charge experiences a force due to the influence of another charged object.

electrical resistance

The ratio of the voltage across a component of a circuit to the current flowing through it: R = V/I. The Systems Internationale (SI) unit for electrical resistance is ohm (equivalent to a volt/ampere).


The capacity of a physical system to do work. The capacity of electromagnetic radiation to do work.

energy potential

The energy that an object possesses due to its position in a force field or that is stored in a system by virtue of the configuration and interaction between bodies in that system, eg elastic potential energy.


All surroundings, both living and non-living.


A state of balance resulting from the application of two or more forces that produce a zero net force.


Points in a field that have the same potential.


A region in which a body experiences a force due to the effects of another body. The effect can be the mass within the bodies, their charges or magnetic properties.


An influence that acts to change the motion of a body or to impose an elastic strain on it.

frame of reference

A coordinate system that enables the position of a body to be specified.


A tentative explanation for an observed phenomenon, expressed as a precise and unambiguous statement that can be supported or refuted by investigation.

independent variable

A variable that is changed in an investigation to see what effect it has on the dependent variable.

inelastic collision

A collision in which the total kinetic energy of the colliding bodies after collision is less than their total kinetic energy before collision.

inertial frame of reference

A reference frame in which a body moves at a constant velocity unless acted on by a net force.


A scientific process of answering a question, exploring an idea or solving a problem, which requires activities such as planning a course of action, collecting data, interpreting data, reaching a conclusion and communicating these activities. Investigations can include practical and/or secondary-sourced data or information.

kinetic energy

The energy that an object possesses by virtue of its motion.


A statement describing invariable relationships between phenomena in specified conditions, frequently expressed mathematically.

linear momentum

The product of the mass (m) and the velocity (v) of a body.


A magnetic material that has been magnetised, ie has a magnetic field.

magnetic material

A material that is capable of being magnetised.

magnetised material

Magnetic material that has magnetic poles.


A representation that describes, simplifies, clarifies or provides an explanation of the workings, structure or relationships within an object, system or idea.

net force

The vector sum of the forces acting on a body.


Relating to a circuit element, whose electrical resistance does not obey Ohmís Law.


Relating to a circuit element, whose electrical resistance obeys Ohmís Law.

photoelectric effect

The process in which a photon ejects an electron from an atom so that all the energy of the photon is absorbed in separating the electron and imparting kinetic energy to it.


Decide on a course of action, and make arrangements relating to that course of action, in advance.

practical investigation

An investigation that involves systematic scientific inquiry by planning a course of action and using equipment to collect data and/or information. Practical investigations include a range of hands-on activities, and can include laboratory investigations and fieldwork.

primary sources/primary data

Information created by a person or persons directly involved in a study or observing an event.


Relating to, measuring, or measured by the quality of something.


Relating to, measuring, or measured by the quantity of something.


An extent to which repeated observations and/or measurements taken under identical circumstances will yield similar results.


An electrical component or material the properties of which limit the flow of an electric current through it.

secondary-sourced investigation

An investigation that involves systematic scientific inquiry by planning a course of action and sourcing data and/or information from other people, including written information, reports, graphs, tables, diagrams and images.


An electrical conductor that is wound into a helix with a small pitch, or into two or more coaxial helices, through which a current passes and establishes a magnetic field, usually to activate a metal bar within the helix and perform some mechanical task.


Not changing over time.


All types of human-made systems, tools, machines and processes that can help solve human problems or satisfy needs or wants, including modern computational and communication devices.


A set of concepts, claims and/or laws that can be used to explain and predict a wide range of related observed phenomena. Theories are typically founded on clearly identified assumptions, are testable, produce reproducible results and have explanatory power.


An extent to which tests measure what was intended; an extent to which data, inferences and actions produced from tests and other processes are accurate.


In an investigation, a factor that can be changed, maintained or measured - eg time, distance, light, temperature.


A quantity having both magnitude and direction.


A measure of the electrical potential difference between two points. The SI unit for voltage is the volt (equivalent to joule/coulomb).

work (in physics)

Work done by a force when the application of that force results in movement having a component in the direction of the applied force.