For the last 50 years, scientists have sought to understand the biochemical and physical processes that take place in liquid H2O. They employed such methods as dielectric relaxation, spectroscopy and nuclear magnetic resonance, but these methods have yielded ambiguous data. Now a group of research-ers from the Institute for Atomic and Molecular Physics in Amsterdam, The Netherlands, has employed a femtosecond mid-IR pump-probe spectrometer to reveal detailed information on the dynamics of how selected molecules interact in the liquid phase.