Insights arising from the atomic theory of matter
By Luke Kristopher Davis
The theory does not coincide with everyday experience
Take a few seconds to look around your present environment; the laptop or PC in front of you, the grass or buildings outside your window, the objects that sit on your table and the body that is you. You can touch the table and it feels quite smooth. Nothing from this experience tells you that matter itself consists of small units called atoms. Objects seem intact and their surfaces seem whole… if they were made of small spherical units surely we would see them? This is not true however.
Humans and their sensory equipment have evolved to deal with the environment around them, our eyes have merely coped with this layer of reality. Our brains find it easier to see objects as big solid objects, not made of tiny tiny particles.
It was in the age of the Athenian philosophers, including Democritus, that the concept of indivisible units of matter arose. The concept arose from the simple empirical fact that objects change; they decay, break, melt and evaporate. They simply asked the question; how can things change if they are completely whole? why doesn’t an object, when broken, simply vanish? The answer to this was atomos: which is Greek for ‘indivisible’. Objects are comprised of very small spheres which are themselves impenetrable.
Many thinkers simply disagreed with this absurd hypothesis for three reasons; 1) There was no obvious physical evidence for it 2) It went against everything already known (in those times conservatism was strong) 3) It didn’t change how they lived.
In 1800’s John Dalton proposed an Atomic theory of matter, which basically stated that substances are made of atoms and that different substances are made of different atoms. His theory was an explanation of many experiments from different scientists. His paper presented strong evidence for the atomic theory.
It seemed that primitive instinct had failed to reveal the truth about the world. Only precise experiments could detect the molecular structure of matter.
Our coarse senses have a limited power in revealing the structure of the universe, experiments that were invented beyond the atomic theory opened a new layer of the universe. They explained so much about where we live and how it works.
The Modern Atomic theory
What Dalton proposed was mostly correct, however he did not present any insight into the structure of these so called atoms. He only said they were there, which at his time was a great achievement. It had taken many physicists and chemists since Dalton to delve deeper into the atom.
J.J.Thomson, through his experiments on Cathode rays, discovered the electron. Which was later found to be a particle orbiting around the nucleus at different energy levels. This finding was partially due to a consequence of the experiments performed by Ernst Rutherford and his assistants (really it was performed by his assistants). The experiment consisted of a gold foil with a detector of helium nuclei around the foil. The assistants fired helium nuclei at the gold foil and most of the helium nuclei past straight through the foil. There were however some unexpected results, some (a statistical value exists) of the nuclei were reflected back to the firer and some deflected their paths. This result was incredible as Rutherford himself explains:
It was quite the most incredible event that has ever happened to me in my life. It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you. On consideration, I realized that this scattering backward must be the result of a single collision, and when I made calculations I saw that it was impossible to get anything of that order of magnitude unless you took a system in which the greater part of the mass of the atom was concentrated in a minute nucleus. It was then that I had the idea of an atom with a minute massive center, carrying a charge.—Ernest Rutherford