The science behind rainbows

Now that summer is rolling in, and the warm weather is beginning to wash away the winter blues, it is time to focus our sights on some of the prettier things the middle months have to offer. Of all the summer sights and scenes you can stumble upon, one reigns high above them all…the rainbow.
A beautiful bridge of colour borne from water and raised high above adoring eyes, the rainbow has always been the pinnacle of celestial grandeur. Even William Wordsworth wrote that ‘My heart leaps up when I behold / a rainbow in the sky’.
Of course, this wouldn’t be a blog from Total Soft Water if we didn’t give you the details; the hard facts behind the gentle rainbow. So, without further ado, let’s go hunt for a pot of gold and find out some cool facts about our colourful friends.
A Light Introduction
First off we need to learn about light, specifically refraction. Refraction is a very common occurrence as light rockets its way around our earth and, as you are about to find out, it can have some spectacular effects!
Refraction occurs when light hits a substance which forces it to change its angle of travel; substances that make this happen are known as having a different “refractive index”, also referred to as optical density.
If the substance causes the light to change speed, it is likely to refract (or bend) more. Another thing to consider is also the “angle of the incident ray”, which essentially translates the angle of the ray of light as it collides with the substance or surface that causes the refraction.
But how does this relate to rainbows? We’ll tell you…
A colourful discovery
Back in the day, a well-known chap by the name of Isaac Newton performed experiments with light and how they are affected by glass prisms. This yielded quite a unique discovery, this being that light is anything but just white! When light is shone through a prism, the refraction causes it to display its true colours, displaying a multitude of colours on the other side… you could say these are “the colours of the rainbow”.
This discovery leads to the scientific fact that all colours are created due to an absence of the colour we see, rather than being completely made of that colour.
This is also how rainbows are formed! It turns out that these raindrops have the same effect as prisms when it comes to refracting the light. Each raindrop meets the light, which is then refracted within the droplet, and then reflects it at the same time; this is what causes the immense dispersion of colour.
But why don’t rainbows just spring up all over the place? Snell’s Law, that’s why. Snell was a mathematician who initially discovered refraction, determining that different substances have different refractive indexes. This means that specific situations are required for the rainbow to occur.
Whilst we can’t confirm or deny that our products will produce rainbows for you, we can guarantee they’ll be just as great! Give us a call on 01462 455772, where we will be happy to explain all of the benefits of our wonderful water filters & softeners.
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