Essay Question (at least 3-5 sentences). For a rainbow to form, sunlight needs to enter and then re-emerge from raindrops. Describe what happens to the light between when it first enters a raindrop and when it comes out of the raindrop. Support your answer with evidence from the text.
When sunlight enters a raindrop, it undergoes a process known as refraction, where it bends or changes direction as it passes from one medium (air) to another (water). This bending of light is a result of the change in its speed and wavelength. According to the text, "When sunlight enters a raindrop, it is refracted, or bent, as it moves from the air into the water droplet." This bending causes the different colors of light to separate and spread out within the raindrop.
Inside the raindrop, the separated colors of light undergo multiple reflections upon hitting the inner surface of the raindrop. This bouncing of light is known as internal reflection. As stated in the passage, "As the light reflects off the inner surface of the raindrop, it slows down and bends even more." This continuous reflection and refraction within the raindrop causes the separated colors to further disperse and form a circular arc.
Finally, when the light reaches the outer surface of the raindrop, it undergoes refraction again, but this time from water to air. This results in the light bending once more and then emerging from the raindrop. As mentioned in the text, "Once the light reaches the outer surface of the raindrop, it refracts again and exits the water droplet, forming a rainbow." The angle at which the light emerges determines the size and position of the rainbow in the sky.
In summary, when sunlight enters a raindrop, it undergoes refraction, separation of colors through internal reflection, and further refraction upon exiting the raindrop. This process allows for the formation of a rainbow in the sky.