12: Temperature and Kinetic Theory Last updated Jun 23, 2019 Save as PDF 11.28: Linear and Rotational Quantities 12.1: Temperature and Heat Page ID18276 BoundlessBoundless ( \newcommand{\kernel}{\mathrm{null}\,}\) Topic hierarchy12.2: IntroductionThe kinetic theory of gases describes a gas as a large number of small particles (atoms and molecules) in constant, random motion.12.3: Temperature and Temperature ScalesCelsius, or centigrade, is a scale and unit of measurement for temperature. It is one of the most commonly used temperature units.12.4: Thermal ExpansionThermal expansion is the tendency of matter to change in volume in response to a change in temperature.12.5: Ideal Gas LawThe ideal gas law is the equation of state of a hypothetical ideal gas (in which there is no molecule to molecule interaction).12.7: Kinetic TheoryPressure is explained by kinetic theory as arising from the force exerted by molecules or atoms impacting on the walls of a container.12.8: Phase ChangesDuring a phase transition, certain properties of the medium change, often discontinuously, as a result of some external condition.12.9: The Zeroth Law of ThermodynamicsThe Zeroth Law of Thermodynamics states that systems in thermal equilibrium are at the same temperature.12.10: Thermal StressesThermal stress is created when a change in size or volume is constrained due to a change in temperature.12.11: DiffusionDiffusion is the movement of particles from regions of high concentration towards regions of lower concentration.