Friday, April 6, 2018

Discovery of Atoms 1808 to 1955


First evidence-based theory: John Dalton's New System of Chemical Philosophy (1808).

The first major discovery that set off modern atomic theory was that atoms aren't in fact the smallest things that exist. J. J. Thompson discovered the electron in 1897.
In the early 1800s, John Dalton used the concept of atoms to explain why elements always react in ratios of small whole numbers (the law of multiple proportions).
For instance, there are two types of tin oxide: one is 88.1% tin and 11.9% oxygen and the other is 78.7% tin and 21.3% oxygen (tin(II) oxide and tin dioxide respectively). This means that 100g of tin will combine either with 13.5g or 27g of oxygen. 13.5 and 27 form a ratio of 1:2, a ratio of small whole numbers.
This common pattern in chemistry suggested to Dalton that elements react in whole number multiples of discrete units—in other words, atoms. In the case of tin oxides, one tin atom will combine with either one or two oxygen atoms.
Dalton also believed atomic theory could explain why water absorbs different gases in different proportions.
For example, he found that water absorbs carbon dioxide far better than it absorbs nitrogen. Dalton hypothesized this was due to the differences between the masses and configurations of the gases' respective particles, and carbon dioxide molecules (CO2) are heavier and larger than nitrogen molecules (N2).
Albert Einstein (1879-1955)
Inventions, research work, or findings that led to inventions, all of these discoveries fall under Albert Einstein accomplishments, and his contributions helped scientists that followed, to further the knowledge and advancements.

Below is an Albert Einstein inventions list, theories, and findings that highlight some of his key contributions:
1.    Quantum Theory of Light – Einstein’s quantum theory of light proposed that light is composed of small packets of energy called photons that have wave like properties. In this theory he also explained the emission of electrons from some metals they’re struck by lightning – this was called the photo electric effect. This theory later led to the invention of the Television, which gave technologists a vision to come up with modern day screen devices (smartphones, computers, laptops).
2.    E=mc2 – He demonstrated the link between mass and energy that led to the nuclear energy today.
3.    Brownian Movement – This could by far be the best Albert Einstein discoveries, where his observation of the zigzag movement particles in suspension, helped to prove the existence of atoms and molecules. And we all know how fundamental this discovery is to almost every branch of science today.
4.    Special Theory of Relativity – This Einstein theory helped to explain that time and motion are relative to their observers, as long as the speed of light remains constant and natural laws are the same throughout the universe.
5.    General Theory of Relativity – Einstein proposed that gravity is a curved field in the space-time continuum created by the existence of mass.
6.    Manhattan Project – Albert Einstein created the science needed to create the Manhattan Project, a research supported by the US that led to the development of the atomic bomb in 1945.
Comments
Einstein was asking the questions his professors didn’t know the answer to in 1900. He was interested in matter, light, time, gravity and electromagnetism. A lot of work had been done in physics and lab instruments had been developed. Einstein was attempting to do was to determine what thing were at their essence.  John Dalton had identified the Atom in 1808, Maxwell described electromagnetism in 1864 and Dmitri Mendeleev had published the Periodic Table of Elements in 1869. But nobody had explained the relationship between matter and energy or light and time. Einstein published his Special Theory of Relativity in 1905. And his General Theory of Relativity in 1915.  He put it all together to be applied throughout the rest of the 20th century.

Norb Leahy, Dunwoody GA Tea Party Leader

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