Final answer:
The phenomena involved in producing the colors and shape of a rainbow are refraction, reflection, dispersion, and the shape and motion of a raindrop.
Step-by-step explanation:
The colours and shape of a rainbow are produced by a combination of several phenomena. Notably, refraction of light as it enters and leaves a raindrop causes the light to bend, and the index of refraction varies with wavelength, leading to the dispersion of light into its constituent colors. Moreover, reflection from the interface between two media, specifically the internal surface of the raindrop, also contributes to the formation of the rainbow. Additionally, the shape of a raindrop and its motion influence the appearance and position of the rainbow in the sky.