Sunglasses have magic function

Many friends, driving is probably encountered similar situation: when encountered heavy rain, even if the wiper hard brush, brush to the speed, also still can't see in front of the line of sight and the vehicles. What is this? One day, small make up from a police friend that, in this case, might as well put on sunglasses, any style are available. So amazing thing happened. All of a sudden, the original beans as a big drain down, covering almost all the line of sight of the downpour, seemed to disappear. Eyes can see, only the rest of the vehicle in front, as clearly and don't have to worry about the line of sight is not clear. What make the sunglasses have so magic? The reason is that because of the light water produces messy reflected light, the sunglasses can filter out the reflected light, make the line of sight becomes clear. Principle is so simple, also don't know the sunglasses this feature you will also prepare a deputy, was caught in a heavy rain might as well try, really good many oh!