This short SPRAY video example shows some test rays travelling through a water sphere. A sharp light beam first hits the center of the sphere and is then moved up. The video shows rays being immediately reflected at the air/water surface, transmitted through the sphere, and leaving the sphere after one internal reflection. The latter are responsible for the appearance of the rainbow.

If you click on the rectangle below and you do not see the video, very likely your PC doesn't support this video format. Sorry!