【英语时差8,16】为什么有的车头灯是蓝色的？（上）（在线收听）

Have you ever been driving along a country road at night, and all of a sudden a car comes around the bend and shines their high beams right into your eyes? Ugh, they’re so bright! You also notice that their lights look a bit bluer than you’re used to. That’s because they might be. Regular headlights are made up of white light, which is a combination of all colors of the rainbow. But these blue lights, while still containing a mixture of all colors, contain more blue wavelengths, making them appear more blue to our eyes. Many luxury cars have these types of lights, called High Intensity Discharge lamps, because the headlights seem brighter under most conditions. But on a foggy night?They actually make visibility worse. Fog is made up of suspended water particles in the air, like a cloud settled down on the earth. But blue light scatters more effectively off these water particles than regular headlights do.