Why does hot tea cool down faster when blown on?

From the surface of hot tea (or water) every now and then the fastest molecules fly out. Some of them evaporate in the form of water vapor, and some return back to the liquid. The fastest molecules flew away – the average temperature of the liquid dropped. If you blow on hot tea, then we will blow off more fast molecules than if they flew away on their own, and the tea will cool down faster. If you increase the area of the evaporated surface (pour tea in a saucer), the process will go even faster.