*Disclaimer: I wrote this blog when I was in grade 11 (2019). It was written passionately and spontaneously. I now look back on the time when I wrote this blog and see it as an important moment in my life. It was a time when I realised more completely my love for learning. So, I encourage you to write about and share that which you are passionate about and what interests you, no matter your age, or however imperfect and unrefined it may be.
“I have no special talents. I am only passionately curious.”
― Albert Einstein
Colour has always interested me. Middle school gave me a very rudimentary understanding of why we can see colour. I was told that certain frequencies of light are absorbed; all other wavelengths of light within the visible spectrum are reflected, resulting in the colour we see. This makes sense. If all blue light is absorbed, we expect to see yellow, the mixture of the remaining colours, green and red. Some may be satisfied with this answer. Not me, though. There are so many questions left unanswered. Why is a substance able to absorb only a specific frequency (or frequencies) of light? Why does the sun create white light, a mixture of all visible (and some invisible) frequencies of light? Not to mention the biology and physics behind how our eyes can produce an image from this.
Being a curious person, perhaps the most confusing question was: why is nobody else thinking this? Am I the only one who’s wondering why? Richard Feynman, arguably the greatest physicist of all time, talked about this. Everyone is satisfied with different levels of an answer.
She fell over.
Why did she fall over?
The ground was slippery.
Why was the ground slippery?
It was made of ice.
Why is ice slippery?
It is very smooth.
Why is ice smooth?
Why is slipperiness the causation of smoothness?
When standing on ice, the surface melts slightly. The liquid molecules ...
Where does it stop? Does it? These are the questions which keep me thinking. All the time. Even this very linear train of thought gets seemingly unnecessarily complicated very quickly. After all, the answer to the first question (the ground was slippery) is enough for anyone to intuitively understand the reason why she fell.
Perhaps being curious is a waste of time. Maybe the pursuit of knowledge is, in the grand scheme of things, irrelevant. What value lies at the seemingly endless abyss of curiosity? I am intentionally equivocating because, ultimately, I don’t know. And I won’t ever claim to. But it’s interesting to think about. That seems to be the paradox in it.
So back to the original question - why do we see colour? Quick Google search will do justice, right? Nope. Just a bunch of generic and insipid responses. Yes, they’re correct, but they’re also superficial and disinteresting. Even a justified speculative answer is far more interesting. Many are satisfied with the surface level. But I wanted to find the answer. This is why we see colour:
It has to do with the resonance frequency of the molecules. Everything has a resonance frequency, the frequency at which things like to vibrate or oscillate. Resonance is achieved when an external force acts in phase which increases the amplitude, the energy, within the osculation. Think of a swing. There is a certain rhythm of pushes which allows for the maximum height to be achieved. This is resonance.
Molecules, too, have resonance frequencies. Thus, when white light contacts a substance, the frequencies of light which align with the resonant frequencies of the molecules are absorbed which cause the molecules to vibrate with a greater amplitude. The rest is reflected. So why are there seemingly infinite colours? Because there are a seemingly infinite number of arrangements and mixtures of molecules. Some are large chains, such as polymers. Some are small, like most gases. A homogenous mixture of molecules will result in a mixture of all the light which the molecules reflect.
So, are you satisfied with this answer? You may be. But, you could probably tell by now, I’m not. Are you? There’s still so much more to know. What affects the resonance of a molecule? Why do molecules only ‘receive’ their respective resonant frequencies of light? After all, you can push a swing out of phase, so why doesn’t this happen with light? It’s interesting how more questions arise when others are answered. Maybe if you have been blessed with the curse of curiosity, you will find the answers to these questions.
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