David L. Chandler reports via MIT News: In recent years, some researchers were perplexed when they discovered that the water used in their experiments, which was contained in a sponge-like material called a hydrogel, was evaporating at a higher rate than could be explained. by the amount of heat or thermal energy. , which the water received. And the excess was significant: a doubling, even tripling, or even more, of the theoretical maximum rate. After performing a series of new experiments and simulations and re-examining some of the results of various groups claiming to have exceeded the thermal limit, a team of MIT researchers came to a surprising conclusion: Under certain conditions, at the interface where water meets the air, light can directly cause evaporation without the need for heat, and this is even more effective than heat. In these experiments, water was held in a hydrogel material, but the researchers suggest that the phenomenon could also occur under other conditions.
This phenomenon could play a role in the formation and evolution of fog and clouds, and it would therefore be important to integrate it into climate models to improve their accuracy, the researchers say. And it could play an important role in many industrial processes such as solar-powered water desalination, perhaps providing alternatives to the step of first converting sunlight into heat. These new findings are surprising because water itself does not absorb light significantly. This is why you can see clearly through several feet of clean water to the surface below. The conclusions were published in the journal PNAS.