Timeline of Theories on Matter

Empedocles was a greek philosopher in pre-Socratic times. He is generally considered the last Greek philosopher to record his ideas in verse. Empedocles, like the Ionian philosophers and the atomists, tried to find the basis of all change. It was Empedocles who established four ultimate elements which make all the structures in the world - fire, air, water, earth. According to the different proportions in which these four indestructible and unchangeable elements are combined with each other the difference of the structure is produced. He made known that nothing new comes or can come into being; the only change that can occur is a change in the juxtaposition of element with element.

Democritus developed systems that made change possible by showing that it does not require that something should come from nothing. There are multiple unchanging material particles, indivisible particles, which persist and only rearrange themselves to form the changing world of appearances. These unchanging indivisible material particles are known as atoms. There are two fundamentally different kinds of realities composing the natural world, atoms and void. Atoms move about in an infinite void, connecting and disconnecting from eachothere, by means of tiny hooks. Atoms are also unchangeable, ungenerated and indestructible. Also, atoms keep properties of the senses, meaning since salt is very salty and sharp the atoms that make up salt may look like shards and in sugar the atoms may look rounded.

Aristotle was born in Greece. He was trained first in medecine, and then in 367 BCE he was sent to Athens to study philosophy under Plato. Aristotle had conflicting ideas with Plato; Ultimately resulting in Aristotle leaving and writting treatises on what he believed. Aristotle fundamentally believed that objects were composed of potential, matter, and their form. He charcteried the change an object undertakes. For example, a block of marble, matter, has the potential to assume whatever form a sculptor gives it.

Evangelista Torricelli was born in 1608 and became an Italian physicist and mathematician. Later in life, Torricelli invented the barometer and aided in the development of integral calculus. Inspired by Galileo's writings, he wrote a treatise on mechanics which impressed Galileo. Two years later, pursuing a suggestion by Galileo, Torricelli filled a glass tube 4 feet long with mercury and inverted the tube into a dish. He observed that some of the mercury did not flow out and that space above the mercury in the tube was a vacuum. Torricelli became the first man to create a sustained vacuum. After much observation, he concluded that the variation of the height of mercury from day-to-day was caused by the changes in atmospheric pressure. Thus, the barometer was invented.

Robert Boyle was one of the leading intellectual figures of the seventeenth century. Boyle was a dedicated experimenter, unwilling to construct abstract theories to which his results had to conform. He was well-known for his work in mechanics, medicine, hydrodynamics, and a wide variety of experiments with his vacuum pump. His major contribution, due to the vast experiments he used with the vaccum pump, was the development of "Boyles' Law". This governs the relationship of pressure and volume of gases being inversely proportional.

Daniel Bernoulli was born in a family of leading mathematicians in 1700. When Daniel turned 13, he went to Basel University to study philosophy and logic. One of the topics he studied with his father was the Law of Vis Viva Conservation—or the Law of Conservation of Energy. He is credited with being one of the earliest writers who made an attempt to devise the kinetic theory of gases and used the idea to further explain Boyle's law. In Russia, Bernoulli and Euler investigated the flow of fluids together, in particular they wanted to better understand the relationship between the speed at which blood flows and its pressure.  To investigate, Daniel experimented by puncturing the wall of a pipe with an open ended straw and noted that the height to which the fluid rose was related to the fluid’s pressure in the pipe. Soon physicians throughout Europe were measuring blood pressure by sticking point-ended glass tubes directly into the artery.But Bernoulli went one step further and realized that per the Law of Conservation of Energy, a moving body exchanges kinetic energy for potential energy as it gains height, and the same holds true of a moving fluid, it exchanges its kinetic energy for pressure. 

Robert Brown was born in Scotland in 1773. Brown used microscopes throughout his adult life. But it was the observation of the incessant agitation of minute suspended particles that Brown's name became inectricably linked. He looked with particular care at the structure of the pollen grains. These he suspended in water and examined them closely, only to see them "filled with particles" that were "very evidently in motion". He also noted that the motion was not due to currents in the fluid, nor from gradual evaporation, but the motion belonged to the particle itself.

Albert Einstein was born in Germany in 1879. Einstein always appeared to have a clear view of the problems of physics and the determination to solve them. He dealt with the classical problems of statistical mechanics and problems in which they were merged with quantum theory: this led to an explanation of the Brownian movement of particles, which he proved and further developed. Albert made known that the motion of perticles on the first path is unpredictable but every path each particle takes after that is predictable.