Final answer:
The colors and shape of a rainbow are produced by refraction, reflection, dispersion, and the shape of a raindrop. Different wavelengths of light are bent by different amounts when entering and leaving raindrops, creating the spectrum of colors seen in a rainbow.
Step-by-step explanation:
Phenomena such as refraction, reflection, dispersion, and the shape of a raindrop are all involved in producing the colors and shape of a rainbow. When sunlight enters a raindrop, it is refracted, or bent, due to the change in medium from air to water, which has a higher index of refraction. As the light enters and leaves the raindrop, it is refracted at different angles depending on its wavelength.
Shorter wavelengths (violet light) are bent the most, and longer wavelengths (red light) are bent the least, leading to dispersion of light into a spectrum of colors. Reflection from the back of the raindrop also plays a crucial role, as it directs the dispersed light back towards the observer.
The spherical shape of raindrops results in the characteristic arc of the rainbow, and the angle at which light emerges from the raindrops determines the position of the rainbow's arc in the sky.