Skin thermal-diffusivity elevation and specific-heat depression.^[102,55] Numerical reproduction of the measured (insets) initial-temperature dependence of (a) the θ (θ_i, t) decay and (b) the skin-bulk temperature difference Δθ (θ_i, t) of warm water. High skin thermal diffusivity due to density loss ensures the characteristic intersection. (b) The Δθ (θ_i, t) arises from the skin lower specific heat because heat flux conserves at the interface.