Here are three simple ways to make a rainbow on your own.
You will observe a rainbow-like spectrum of colors in the stream of water. Try adjusting the spray with the nozzle. You will be able to change the intensity of the colors that you see and the width of the rainbow.
Rainbow #3 - A "greenbow":
In conducting these experiments you saw that you don't need a rain shower to see a rainbow. You simply need the right conditions. Light, water, dispersion, and reflection are what it takes to make a rainbow. This is why you can see a rainbow in your sprinkler on a sunny day.
For the third experiment you learned that by manipulating the conditions you could effect the outcome. By adding the milk the violet rim of the spectrum was changed from violet to green.
This happens in the atmosphere as well. During the phenomenon of green flash, most of the violet and blue rays are scattered by air molecules. The introduction of milk into the water "scattered" the violet and blue rays of the spectrum coming from the glass rainbow.
©Copyright 1998 Elizabeth
Beckett, Holly Bernitt, and Vishwa Chandra.