Thermal resistance is the reciprocal of thermal conductance. Heat transfer through materials is analogous to electrical resistance. Temperature difference is the driving function for heat flow
Tables provide properties of various substances at different temperatures. Data includes molar mass, gas constant, and ideal-gas specific heats. Properties cover boiling points, melting points, and densities
Steady heat transfer maintains constant temperature or heat flux over time. Transient heat transfer varies with time and location. Heat transfer is one-dimensional when occurring primarily in one direction. Heat transfer is two-dimensional when third dimension effects are negligible
Liquid is a nearly incompressible fluid with constant volume but no fixed shape. Made up of vibrating particles held together by intermolecular bonds. Only state with definite volume but no fixed shape. Density is higher than gas but lower than solid
Thermal resistance quantifies heat conduction difficulty. Thermal resistance is calculated as temperature difference divided by heat flow. JEDEC uses θ for ICs, IEC uses Rth for discrete devices. Thermal resistance units are K/W or °C/W
Heat flux is energy flow per unit area per unit time. SI units are watts per square metre (W/m²). Heat flux is a vector quantity with direction and magnitude. Heat flux is denoted by q, unlike mass or momentum flux