Comparison of crystalline and amorphous ice topography. Left panel: STM image of a noncrystalline ice film, average thickness 6 nm, grown at 145 Κ on Pt(111). Surface steps of bilayer height (0.37 nm) are easily resolved. Right panel: same, for a 6 nm thick amorphous ice film grown at 100 Κ on Pt(111), revealing high surface roughness at nanometer scales. Two surface steps are visible in the otherwise atomically flat Pt(111) substrate, replicated by the amorphous ice film. Data originally taken by Thürmer & Bartelt (2008).