How rainbow form thought in my physics class

https://en.wikipedia.org/wiki/en:Creative_Commons

rainbow is caused by sunlight and atmospheric conditions. Light enters a water droplet, slowing down and bending as it goes from air to denser water. The light reflects off the inside of the droplet, separating into its component wavelengths--or colors. When light exits the droplet, it makes a rainbow.

rainbow is an arc of color in the sky that can be seen when the sun shines through falling rain. The pattern of colors starts with red on the outside and changes through orange, yellow, green, blue, indigo to violet on the inside.
A rainbow is created when white light is bent (refracted) while entering a droplet of water, split into separate colours, and reflected back. On the ground, the bottom part is hidden, but in the sky, like from a flying airplane, it can be seen as a circle around the point opposite the Sun.

rainbow is most often viewed as a circular arc in the sky. An observer on the ground observes a half circle of color with red being the color perceived on the outside or top of the bow. Those who are fortunate enough to have seen a rainbow from an airplane in the sky may know that a rainbow can actually be a complete circle. Observers on the ground only view the top half of the circle since the bottom half of the circular arc is prevented by the presence of the ground and the rather obvious fact that suspended water droplets aren't present below ground. Yet observers in an airborne plane can often look both upward and downward to view the complete circular bow.