An optical phenomenon that appears when sunlight and atmospheric conditions are just right, rainbows are one of nature’s most beautiful and intriguing displays. Have you ever wondered how and why they occur and what makes them so colourful? Abernethy Owens is the optometrist Perth families rely on for high quality eye care and thorough eye examinations. Let’s take a deeper look at the reason why we see rainbows and what gives them their stunning array of colours.
Refraction and Rainbows
Refraction is the bending of light as it passes from one transparent substance into another. We see rainbows right after it rains, that is because rainbows require water droplets to be in the air. When sunlight shines on to those water droplets, the light moves into the water and bends (refracts). This is because light travels slower in water than in air due to its denser nature. The light speeds up again as it exits the water droplet, and ‘bends’ back the way it came.
Why The Colours?
Sunlight is made up of many wavelengths (colours) of light: red, orange, yellow, green, blue, indigo, and violet. When those colours enter the water droplet, some of them refract more than others. Violet is the shortest wavelength of visible light and therefore bends the most, while red is the longest wavelength of visible light and bends the least. When the light exits the water droplet, it is separated into its component wavelengths with violet on the bottom and red on the top and the others in between.
Sometimes there may be a faint secondary rainbow that can sometimes be seen, this is caused by each ray of light reflecting twice on the inside of each droplet before it leaves. In this secondary rainbow, the colours are reversed red will be at the bottom, and violet at the top.
While seeing a rainbow after a rain storm is beautiful, natural occurrence, seeing rainbows or halos around light in everyday life indicates that there may be a problem with how light is filtering into your eyes. In normal vision, the different wavelengths of light are focused on a single point so you can't distinguish them. Seeing rainbows or halos could be caused by opaque spots on the cornea, such as cataracts. Cloudiness on the lens may cause light that passes into the eye to abnormally scatter or bend.
A Thorough Eye Examination Can Diagnose Eye Problems Early
A comprehensive annual eye exam can detect all sorts of health problems that may have otherwise gone undetected. If left untreated, many eye diseases can significantly impact everyday life and eventually cause total blindness. Eye tests can also help to detect problems with your overall health so visiting your optometrist every year not only protects the health of your eyes, but also your body.
If you have noticed any changes or irregularities in your vision, or you would like to book in for a thorough eye examination to ensure your eyesight remains in optimal condition, get in touch with Abernethy Owens today. With 5 convenient locations throughout Perth, stop searching for a ‘professional eye exam near me’ and make an appointment with our friendly team online now.