Welcome! Today we'll explore one of nature's most spectacular displays: the rainbow. A rainbow forms when sunlight encounters tiny water droplets suspended in the air, creating a magnificent arc of colors across the sky.
The key to understanding rainbows lies in the nature of white light. What we see as white sunlight is actually composed of all the colors of the visible spectrum. When this white light enters a water droplet, something magical happens - the light separates into its component colors through a process called dispersion.
Now let's see what happens step by step inside a water droplet. First, when sunlight hits the droplet, it refracts or bends as it enters the denser water medium. Then, the light travels to the back of the droplet where it reflects off the inner surface. Finally, the light refracts again as it exits the droplet, bending once more and separating further into distinct colors.
Here's the crucial part: different colors of light bend at slightly different angles when they refract. Red light, having the longest wavelength, bends the least and exits at about 42 degrees. Violet light, with the shortest wavelength, bends the most. This angular separation is what creates the distinct bands of color we see in a rainbow, with red on the outside and violet on the inside.
And here's the complete picture! When sunlight shines on millions of tiny water droplets suspended in the air after a rain shower, each droplet acts like a miniature prism. Together, they create the spectacular arc of colors we see as a rainbow. The observer must be positioned at just the right angle - about 42 degrees from the antisolar point - to witness this beautiful natural phenomenon. This is why rainbows appear opposite the sun in the sky.