My Essay (Part III) - Galileo to Newton

Newton's Principia, with his actual pen-strokes on correction.

Galileo not just only discovered there are other moons on other planet. He also proposed that all things move due to acceleration of gravity. This was demonstrated by Galileo, as rumour has it, was done at the top of the Pisa tower when he dropped two balls, one ball made of iron and the other made of wood. The result is that both balls of the same size dropped at the same time landed on the floor together at the same time suggest that different weight does not affect the speed of the balls. Another experiment was he put a ball on an incline plane and let it roll from the top to the bottom and he found that the ball is moving faster and faster. We call it accelerating. So the question is what drives the ball to accelerate?

The legacy of Galileo was indeed profound and it made an impact as how science is done. As quoted from physicist Leon Lederman’s book: The God Particle

“For our purposes, he (Galileo) was a physicist, and a great one, far beyond his advocacy of Copernicanism. He broke new grounds in many fields. He blended experiments and mathematic thinking. When an object moves, he said it’s important to quantify its motion with mathematical equation. He always asked “how do things move? How? How?” But he didn’t ask “Why? Why is the ball falling?” He was aware that he was just describing motion, a difficult enough task for his time.”

Galileo didn’t mention that why the ball is falling, and that needed another great mind to solve the puzzle. Enter Isaac Newton. Sir Isaac Newton is perhaps one of the greatest minds of all time. He revolutionised the way we see how objects move and he literally created a new branch of mathematics for it. In 1687, Newton published the celebrated “Philosophiae Naturalis Principia Mathematica” which is perhaps the single most important work ever published in physical sciences.

In the seminal masterpiece, Newton described how everything in this universe worked – Force. In the papers were three immutable laws that describe all motions in the universe. Suddenly, the universe became a measureable, definite clockwork. The first law was the concept of inertia, which is a fancy word that simply means: an object does not move or moves in a constant velocity until an external force acts on it. This is particularly useful in your life when you tried to get your ketchup conveniently by hitting at the bottom end of the bottle repeatedly, the sudden force acting on the bottle propel the sauce out from its bottle. The second law is quite simply F = MA. It’s a simple mathematical relation. Let’s read it out loud; “Eff equals to Emm Ayy”. What that means was the force is equal to the product of the mass and the acceleration of the object. The third law is better. It says that when a force is exerted on an object, the object exerts the same force back on the opposite direction. (Every action there’s a reaction). So next time if someone bitch-slapped you, don’t bother. Because your face already slapped that person’s hand on that painful moment! (You felt pain more due to the more pain receptors on the surface of your cheek than the slapping palm)