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The questions of Newton


Isaac Newton was a genius in many fields from pure mathematics to, of course, physics - he developed the laws of motion and the law of universal gravity. But arguably and far less known, was that his first love was optics.

In the 17th century, there was one particular problem that confounded people. When light was shone through a prism or glass, it refracted into a rainbow of colours. How does white light become different colours? People couldn't understand back then, but the belief was the impurities in the prism must have corrupted the light, causing it to split.

Newton was naturally also fascinated. At his window, he cut a variety of holes so that light can enter through different angles. He wanted to test if this affected refraction. It didn't. No matter how he tried, white light was refracted into different colours.

Consequently, Newton posited this theory - light was inherently made up of different colours, and the prism merely revealed this.

As with any new scientific hypothesis, there was fierce opposition. People persisted with the original belief that the refraction of light was because the prism contained impurities. It just seemed so counter intuitive that white light, which appears white, is not actually white. And if it wasn't white, why are there so many different colours that emerged? Where did these colours come from?

Some of the supporters of Newton's theory pushed to prove their case. They would polish the prism, making it as unblemished as possible. But no matter how much they polished, critics would still claim that there must be impurities in the prism.

Trust Newton to have a solution. In response to his critics, instead of arguing about the purity of the prism, he went the other way. If one prism caused light to refract because of impurities, what if we added a second prism?

He placed a second prism (upside down) after the first. If prisms always contained impurities, passing the light through 2 prisms will cause it to refract even more.


Instead, when white light was shone through both prisms, the refracted rainbow of colours recombined after passing the second prism back into white light.


Newton was right.

Indeed, Newton had a knack of asking very good questions, enabling him to advance his thinking. He was the one who didn't fixate with the argument about the purity of the prism. Instead, he fashioned a question no one had consider: "What if I added a second prism"?

Similarly, it was through a question that he figured out gravity (the concept, not the precise mechanics which was developed later by the likes of Einstein).

Contrary to popular belief, Newton did not ask himself why the apple fell from the tree. (This is the sort myth that started spreading because humans have an annoying inclination to simplify and to believe simple messages).

Newton already knew that the apple would fall downwards. there's no surprise about this. Instead, his question was far more nuanced: "Why does the apple fall down towards Earth, but the moon (in the background) does not?"

If you think about it, this question is far more useful in considering gravity.

Perhaps sometimes, we get stuck in life or in arguments not because our thinking is incorrect at the first instance, but the question we answer simply wasn't sharp enough.


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