Before revision: Mathematical statement Newton's law is mathematically stated by the simple first-order differential equation: where Q is thermal energy in joules h is the heat transfer coefficient between the surface and the fluid A is the surface area of the heat being transferred T is the temperature of the object's surface and interior (since these are the same in this approximation) Tenv is the temperature of the environment ΔT(t) = T(t) - Tenv is the time-dependent thermal gradient between environment and object Putting heat transfers into this form is sometimes not a very good approximation, depending on ratios of heat conductances in the system.
After revision: Mathematical statement Newton's law is mathematically stated by the simple first−order differential equation: where Q is thermal energy in joules h is the heat transfer coefficient between the surface and the fluid A is the surface area of the heat being transferred T is the temperature of the object's surface and interior (since these are the same in this approximation) Tenv is the temperature of the environment ΔT(t) = T(t) - Tenv is the time-dependent thermal gradient between environment and object Putting heat transfers into this form is sometimes not a very good approximation, depending on ratios of heat conductances in the system.