The rainbow is an optical phenomenon in the form of an arc caused by the rays of sunlight that are refracted in the drops of water suspended in the atmosphere creating the spectrum of seven colors: red, orange, yellow, green, blue, indigo and Violet.
The rainbow forms different colors when sunlight enters the water droplets and refracts one of the seven colors. As the light refracts at different angles and at different speeds, we can see the full spectrum of rainbow colors.
Rainbows can be observed in the opposite direction of the sun, that is, where the sun’s rays are directed. The rainbow arc is formed due to the reflection of the colors in our eye cone that is cut in the middle by the horizon.
The rainbow phenomenon was first studied by Isaac Newton in 1665 in the field of optics. The curiosity towards this phenomenon arose with the observation of the same colors when the light entered a prism.
The refraction (change of direction and velocity) and the reflection (change of direction of the wave) of the light studied in physics became the basis of the phenomenology of optics that ranges from the study of natural phenomena to the construction of astronomical telescopes.