In contrast to the sigmoidal dependence of the number of net-aligned Stern layer water molecules on applied potential shown in Fig. , the right-hand axis of Fig. shows that water flipping is linear in the total potential across the electrode:electrolyte interface. Flipping all the Stern layer water molecules requires a field of close to -1 x 10 7 V cm -1 (top x-axis in Fig. ) -an experimental match with estimates from classic electrochemical textbooks Eflip= Ftot . e . 𝒩water↓, showing a sigmoidal variation with applied potential (Fig. ). In contrast, we find a parabolic variation of the Stern layer energy density with f↓, the fraction of Stern layer water molecules pointing their oxygen atoms towards the electrode (Fig. , note that for f↓=0.5, 𝒩↓=0, i.e. there is no net order, and for f↓=1.0, 𝒩↓= 𝒩↓,max, i.e. all water molecules have flipped). The experimental results can be interpreted using a 2-dimensional, two-state Ising model in which we express F, the Helmholtz free energy mean field solution for the square lattice model (z=4), according to (44)