As we approach the peak of summer, rain showers are in full gear. We live in a tropical environment where a 40% chance of rain is a daily occurrence. No need to fear these pop up showers though. Most of the time, if it does rain, it passes over quickly, leaving behind calm waters, cooler air and rainbows. Recently on many trips, we have avoided pop up showers, but by doing so we were lucky enough to enjoy the view of a beautiful rainbow over the water. Sometimes we have even seen a double rainbow. Have you ever wondered why rainbows form? I have and so have my customers.
Rainbows appear from a refraction of light shining through many rain droplets. It works just like a prism would refract light. Refraction is when the sunlight (or light) is separated into different wavelengths. These wavelengths would be visible to us in the form of colors. Remember in science class when you looked through the triangle shaped piece of glass towards the light? Most likely you saw a rainbow. The rainbow we saw would be the light being refracted through the prism into different colors forming the rainbow. Once you saw the colors, you then learned about the term ROYGBIV, (red, orange, yellow, green, blue, violet, and indigo) -the color spectrum.
Different colors travels at different speeds, through different mediums. When light travels through air, it travels very fast, but when it travels through water or glass it travels at different speeds. Red light travels faster than blue light. Slower colors bend more when moving through glass or water. So, with this in mind, the next time you look at a rainbow you will notice the outside color is usually red or pink and the inside color is usually blue or indigo. This follows the ROYGBIV spectrum
I bet you are wondering why rainbows in the sky are arced and the one in the prism is not. The answer is that because raindrops are circular in shape when falling in the sky, the sunlight refracts through the sphere, bouncing off the circular form creating an arc of colors. According to scientists, rainbows only occur when sunlight is being refracted at a 48° angle, which is what makes seeing rainbows after a rain shower so rare.
A double rainbow or triple rainbow is even more rare. When a double rainbow forms it is usually not as bright as the first rainbow. This is because the light has been refracted through the raindrop twice. Basically the light is refracted through one side of the rain drop and then sent back in and refracted back out the other side of the raindrop. When this occurs the ROYGBIV color pattern is reversed; the inner portion of the rainbow would now be red instead of blue and the outside would be blue instead of red. It is possible to have triple and quadruple rainbows but they are extremely uncommon.
Another “rainbow” phenomenon you might see in the sky on our tours is known as a solar or lunar halo. This is an iridescent color way up in the clouds. This is caused by light refracting through tiny raindrops or ice crystals in the clouds. It doesn’t form an arc because it is just a form of moisture and not an actual circular raindrop falling to the ground.
While rain storms can be scary and temporarily take away the sunshine, it is best to always look for the bright side…and a rainbow.