In the previous lesson, we learned about the way light travels. Light travels in a straight path, but can reflect off of surfaces and refract through certain ones. In the picture above, the traffic light is reflecting off the wet ground, creating horizontally polarized light. Because the surface of the ground is wet, the light is able to reflect off of it. The angle of incidence and the angle of reflection (separated by the dotted line or normal) are equal to each other as you can see in the animation.