Rainbow Among Us
By Jillian Smoker, Grade 7
Do you remember a time when you saw a rainbow and thought you saw its end, thinking that you had found where the pot of gold was? Sadly, rainbows don't really have pots of pure gold at their ends, but they can still be seen as a wonder of science.
How Rainbows Form
Since a rainbow is only an optical illusion, the occurrence of it forming depends on where the viewer is and where the sunlight or another light source hits the water droplet at a specific angle of 42 degrees. This means the light source would have to come from behind the viewer, and the center of the rainbow would then form at the antisolar point (the point exactly opposite from the sun).
When light enters a water droplet, it is refracted or bent, and it then reflects or bounces back from the back of the droplet to form the rainbow. Each color is reflected at a different angle, creating the different colors in the same order when the rainbow forms.
The Spectrum
The spectrum consists of both visible and nonvisible light. All the colors of the rainbow, both visible and nonvisible, have different wavelengths, which refer to the distance between each crest in the wave, and frequencies, which are the rate at which a vibration occurs.
The shortest wavelengths with higher frequencies start at gamma rays, X-rays, ultraviolet light, and then go to the visible light (with the colors violet, indigo, blue, green, yellow, orange, and red). The longer waves with lower frequencies start at red then on to infrared rays, radar waves, microwaves, television waves, and radio waves.
The light with shorter wavelengths are higher in energy, and they can be more harmful to organisms. Ultraviolet light causes sunburns, x-rays help doctors to see inside a human body and are used in medicines, and gamma rays, the most dangerous of all, can be used to treat cancer but are very harmful when they are not used properly.
Light with longer wavelengths are lower in energy and many are used for some source of communication. Infrared light emits thermal energy or body heat, microwaves make water molecules in food vibrate to heat the food, and radio waves modify and amplify sound waves to serve as a communication device.
Citations:
https://education.nationalgeographic.org/resource/rainbow
https://bluebox.creighton.edu/demo/modules/en-boundless-old/www.boundless.com/physics/textbooks/boundless-physics-textbook/geometric-optics-24/reflection-refraction-and-dispersion-169/dispersion-rainbows-and-prisims-611-6326/
https://www.britannica.com/science/light
https://science.nasa.gov/ems/01_intro
https://www.universeoptics.com/what-is-non-visible-light/