In recent years, experiments from different groups have reported that evaporation under sunlight from hydrogels and other porous materials can exceed the thermal evaporation limit by several times, i.e., super-thermal.  We hypothesize that photons can directly cleave off water clusters at the liquid-vapor interface in a way similar to the photoelectric effect, which we call the photomolecular effect.  We carried out over 20 different experiments on both hydrogel and a water-air interface to demonstrate this effect.  Some key experiments include: (1) partially wet hydrogels become absorbing despite their constituent materials are transparent; (2) super-thermal evaporation; (3) polarization, angle-of-incidence, and wavelength dependences of optical responses at a single air-water interface to visible-light where bulk water does not absorb; (4) cooling of air under visible light irradiation; and (5) Raman and IR signatures of water clusters in the air.  We also demonstrate that visible light heats up a thin layer of fog, with temperature rise peaking at the green wavelength where water is least absorbing.  Our work could resolve an 80-year puzzle in atmospheric science: experiments reported more cloud absorption than theory could predicts. Progress in theoretical description of the photomolecular effect will also be summarized.  Our study suggests that the photomolecular effect should happen widely in nature, from clouds to fogs, ocean to soil surfaces, and plant transpiration, and can also lead to new applications in energy and clear water.