A discussion of light diffraction and how to form your very own double rainbow.
Some media may contain mature content. Discretion is advised when viewing with students.
This lesson is a great way to open up a physics unit on light diffraction and lenses. Begin by showing the class the first YouTube video of the Double Rainbow. Ask the class to list what they know about rainbows and how they form. Make sure to note student responses and to clarify any misinformation they may have. After this, make sure students understand that a rainbow occurs when sunlight shines onto water droplets including rain, waterfalls, sprinklers, etc. The sunlight enters a water droplet, is refracted on the way in, and bounces back out of the water droplet. When the light exits the water, it is broken into the color spectrum since sunlight is made up of all the colors. Although the rainbow is an enormous amount of colors, the human eye is not able to see all of them, therefore, we classify the colors into Red, Orange, Yellow, Green, Blue, Indigo, and Violet (Roy G. Biv).