The results of Molecular Dynamics simulations of a water lamella between platinum crystals and of water on a Pt(100) surface for different degrees of coverage are reported. The flexible BJH model of water is employed and the Pt-water interaction potential is derived from extended. Hückel molecular orbital calculations. The influence of the Pt(100) surface on the structural and dynamical properties of water is significant only for the adsorbate layer but depends on the degree of coverage. The calculated work function change and its dependence on coverage is in good agreement with experimental results. The spectral densities of the hindered translations, librations, and vibrations derived from the simulation by Fourier transformation of velocity autocorrelation functions compare favorably with electron energy loss spectroscopic measurements.