I had the "stupid moment" of the day. The thermal effects of evaporation on a surface is that the surface actually cools down -- so I could not get the "it prod

I had the "stupid moment" of the day. The thermal effects of evaporation on a surface is that the surface actually cools down -- so I could not get the "it produces heat" part. After drinking my morning coffee I realized that the heat transfer is from the surface to the water droplets/vapors that then carry it to the next layer of this still. Ergo: coffee makes you smarter and I shouldn't be on HN so early in the morning.