A Brief History Of Physics
What is Physics?
Physics (from Ancient Greek: φύσις physis ”nature”) is a natural science that involves the study of matter and its motion through space and time, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.
There is certainly a lot to add to this but we will talk about that later.
How did Physics start?
A little over 2,000 years ago Physics made its first real appearance through the writing of Aristotle (top left) who wanted to describe the properties of Motion. Aristotle divided motion into two main classes: Natural Motion and Violent Motion.
Natural Motion was thought to proceed from the “nature” of objects. Aristotle believed that all matter was made up of aether, or some combination of four elements: earth, water, air, and fire. According to Aristotle, every object in the Universe had a proper place, determined by this nature; any object not in its proper place would “strive” to get there, with heavier objects “striving” even more so. So a stone would fall towards Earth because it is of Earth and smoke would rise because it of Air. Being a mixture of Air but predominately Earth, a feather would fall to Earth but not as rapidly. Natural motion consisted only of motions straight up or straight down, as with all things on Earth, or in a circular motion, as was the case for the celestial objects. Circular motion was seen as being without a beginning or an end and would repeat without deviation. Also Aristotle asserted that celestial objects were made of ether and thus did not have to obey the same rules as Earthly objects.
Violent Motion resulted from pushing or pulling forces. Violent motion was imposed motions such as throwing a rock or the wind in the sails of a ship. However this concept had its difficulties, for the source of the motion was not always evident. For example, a bowstring moved an arrow until the arrow left the bow; after that, further explanation was needed for why the arrow continued to move. It was imagined that the parting of the air created by the moving arrow created a squeezing effect on the rear thus pushing it through the air much like squeezing one end of a bar of soap with a wet hand.
Although Aristotle did not consider these to be the final words on the subject, his followers regarded his views as beyond question for nearly 2,000 years. Because the natural state of an object was to remain at rest, it was obvious to people that the Earth must also be at rest since a force capable of moving it was inconceivable.
It wasn’t until Copernicus (top right) suggested the idea that the Sun, not the Earth, was the centre of the universe that anything began to change. Because the views of Aristotle had been adopted by the Christian Church, Copernicus waited until the last days of his life to have his work De Revolutionibus printed for fear of prosecution. Then in the 16th century Galileo (bottom left) was able to discredit the Aristotelian view of motion and by extension giving credence to the work of Copernicus. It is said that he demonstrated this by dropping two stones, one twice as heavy as the other, from the Leaning Tower of Pisa and observing them hit the ground at the same time. Galileo also did a lot of work with inclined planes which we will talk about in another post.
Sir Isaac Newton (bottom right) an English physicist, has been considered by many to be the greatest and most influential scientist who ever lived. His monograph Philosophiæ Naturalis Principia Mathematica, published in 1687, laid the foundations for most of classical mechanics. In this work, Newton described universal gravitation and the three laws of motion, which dominated the scientific view of the physical universe for the next three centuries. Newton showed that the motion of objects on Earth and that of celestial bodies is governed by the same set of natural laws thus advancing the scientific revolution. The Principia is generally considered to be one of the most important scientific books ever written, both due to the specific physical laws the work successfully described, and for its style, which assisted in setting standards for scientific publication down to the present time.
Where does this leave us?
It was through these great minds, and many others I was unable to mention for the sake of brevity, that Physics was born. With the introduction of Physics we have been given modern society as we know it. An understanding of Physics has given us the ability to use the nature of the universe we live in to work for us. However this understanding doesn’t come easy. The universe is constantly speaking to us, telling about itself. From basic mechanics to General Relativity, mathematics has been the tool used to enable us to decode what the Universe is saying. It is the most fundamental of questions that Physics ask, and it is through the use of mathematics that we are able to answer them. It is through the use of mathematics that we are able to understand the Language of the Universe.