Discovery
It is interesting that if you ask a small child whether the Earth is flat or spherical, he’d probably tell you the correct answer. Yet, if you ask them how they relate the seemingly flat ground to a spherical Earth, I’m sure not many can tell you.
I was thinking back today, how old I was when I first learned that the Earth was round. I can frankly admit that I can’t remember it. That probably means I learned about it when I was very young. What I do remember is that my mom bought me an inflatable plastic Earth balloon, probably with the intention for me to learn about the 7 continents on Earth. I’m sorry to say that the naughty and playful child that I was, I did not learn anything from it. Rather, I treated it as my soccer ball more often than not.
Another interesting question which a young child might ask is gravity. I vaguely remember asking my mother why everything seemed to fall towards the ground(of course, in my mind then, birds are one of the few exceptions). She answered that it is due to gravity. Of course, in Mandarin, direct translation will be the Attractive Force of the Heart of Earth. Well, being the inquisitive child that I was, I was surely to ask what gravity is. I am not sure how my mother answered me, but I grew up attributing gravity as the natural property of Earth. As for how gravity come about, that was one question I did not understand until merely a few years ago.
When I first read about the greatly speculated experiment supposedly done by Galileo, where he dropped balls of different mass from the tower of Pisa and proved that balls of different mass reaches the ground at the same time, it seemed quite unacceptable to me. When I read that a lead ball and a feather would reach the ground on the same time given that they are released from the same height, that sounded totally absurd to me. A lead ball is heavier than a feather, of course it would drop to the ground faster! Funny that I didn’t really realize how big an impact air resistance can give rise to, even when I knew how parachute works.
Then comes the Newton’s Laws of Motion. The First Law - an object will remain at rest or in motion unless acted on by an external and unbalanced force. What an absurd statement it was to me. Just look at my toy car, if I push it it will move, and finally, it will stop! The natural state of an object must be the state of rest. In the absence of external and unbalanced force, surely everything will come to a state of rest, won’t they? The Second Law sounded natural to me, the harder I push my toy car, the faster it goes. Yippy! Now the Third Law - For every action, there must be an equal but opposite reaction. Hmm… it was somewhat true, but there is a problem: If I push a wall, the wall somewhat miraculously know what I am pushing it and it will push me back, as if it’s alive? Ah… such were the days.
The Law of conservation of energy was one knowledge that I quite easily accepted. If I want to make a ball move, surely I need to put in energy by kicking it. If I want to use a torchlight, surely I need to supply electricity by using batteries. And of course, there is the pendulum. The height the weight reaches is always nearly the same (yes, by then, I have understood the idea of air resistance and frictional force, sadly though, I could only think of those two as the causes of retardation in the system). A thought experiment, probably by Galileo, is such that a ball is dropped from a certain height along a U-shaped frictionless track, it will always go up to the same height where the ball is first dropped. Hm… that makes sense…. Then comes a slight alteration to the thought experiment. If half of the U-shaped track is removed and replaced with an infinitely long straight track, the ball would keep on moving forever. AHA! Suddenly, Newton’s First Law made sense to me, finally.
When learned that the universe has no boundary, it came as a shock to me. Surely, everything must have a boundary. I imagine something small, say… a tin can. There is cylindrical, with a top and a bottom. Take something bigger, a car, there are a doors and windows. Alright, something bigger, the Earth. There’s the ground and there’s the sky (or rather, atmosphere). If I keep moving straight at one direction, surely at some point, I will reach a dead end. I can only laugh when recalling that I thought the universe is somewhat like the Earth… with walls. On the 6 side (yes, somehow, I prefer cubes at that certain point of my life), there are wall and on the bottom, there is a vast expense of water… As for the planets, well, they just hover in “mid-air”. Obviously they won’t drop down, with no gravity to pull them down.
Now comes Einstein’s crazy “time is not a constant” and “4th dimension” thing. Can you even imagine something in 4-dimensions? Frankly, until now I can’t. And what did he meant by time is not a constant? Surely… No, certainly, if we both have a good clock, we would both measure the same passing of time. Time is just time. How can the velocity that one is traveling affects the “speed” of one’s time? Ah… what a funny joke my friend cracked, running passed me and yelling, “I’m becoming younger!”
Undoubtedly, I have come a long way from the “why do everything drop to the ground” child that I was. It is a life full of discoveries, how I realize that my assumptions, which at that moment seemed totally logical, turn out to be a long way from even the word “correct”. What I can be certain now is that what I think to be the truth now can be actually wrong. There are always changes in our life, and certainly in our understanding of the world. That is exactly what makes life so interesting. Or… maybe I’m wrong…