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Historical development of atomic theory
Historical development of atomic theory
Development of atomic theory and contributors
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The Atomic Theory is a theory that explains what matter is made of. The Atomic theory states that matter can’t be divided as it is made up of minute particles called atoms that cannot be separated. The very word atom is derived from the Greek word Atmos which means indivisible.
Atomic theory timeline-
Year Person/People Event
442 BCE Democritrus and Leucippus These Greek philosophers came up with the idea that all matter is composed of indivisible elements.
1803 John Dalton British chemist and physicist John Dalton theorised that matter is composed of spherical atoms (that are in motion) of different weights and are combined in ratios by weight.
1896 Wilhelm Rontgen Discovered that certain chemicals glowed when exposed to cathode rays. These chemicals were special because they weren’t deflected by the magnetic field produced in the cathode ray tube (which was built by Sir William Crookes in 1870).
He Called these X-rays.
1896 Henri Becquerel Accidentally discovered spontaneous radioactivity.
1898 Pierre and Marie Curie Pierre and Marie hypothesised that radioactive particles cause atoms to break down, then release radiation that forms energy and subatomic particles.
1898 JJ Thomas Discovered the electron, using properties of cathode rays.
1900 Max Planck Introduced the quantum theory- stating that electromagnetic energy could only be released in quantized form.
His ‘quanta’ are now referred to by physicists as ‘photons.’
1905 Albert Einstein Created special and general theories of relativity and speculated upon the particle nature of light. This was the basis of understanding nuclear energy.
1908 Robert Millikan Measured the charge of an electron. The charge of one electron is known as the elementary charge.
1909 -- Ernest ...
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...ces are secondary sources, I had to be very careful that the websites that I chose contained reliable information and diagrams. I believe that I have been very careful with my sources and have chosen ones that are both accurate and informative and have helped me to develop my ideas about Marie Curie and the atomic theory in many ways.
Works Cited
http://www.softschools.com/timelines/atomic_theory_timeline/95/ http://www.nobelprize.org/nobel_prizes/themes/physics/curie/ http://www.buzzle.com/articles/accomplishments-of-marie-curie.html http://www.aip.org/history/exhibits/curie/resbr2.htm http://www.earthmagazine.org/article/benchmarks-henri-becquerel-discovers-radioactivity-february-26-1896 http://www.aps.org/publications/apsnews/200412/history.cfm http://www.nist.gov/pml/general/curie/1927.cfm
http://www.aip.org/history/curie/brief/03_radium/radium_2.html
Her hypothesis was this: The emission of rays from Uranium compounds could be an atomic property of the element Uranium-something built into the very structure of the atoms. During Marie's time, the atom was thought to be the smallest particle in existence.... ... middle of paper ... ...
In 1803 this theory was finalised and stated that (1) all matter is made up of the smallest possible particles termed atoms, (2) atoms of a given element have unique characteristics and weight, and (3) three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules).
An atom, by definition, is the smallest part of any substance. The atom has three main components that make it up: protons, neutrons, and electrons. Protons and neutrons are within the nucleus in the center of the atom. The electrons revolve around the nucleus in many orbitals. These orbitals consist of many different shapes, including circular, spiral, and many others.
In the 1920s the new quantum and relativity theories were engaging the attentions of science. That mass was equivalent to energy and that matter could be both wavelike and corpuscular carried implications seen only dimly at that time. Oppenheimer's early research was devoted in particular to energy processes of subatomic particles, including electrons, positrons, and cosmic rays. Since quantum theory had been proposed only a few years before, the university post provided him an excellent opportunity to devote his entire career to the exploration and development of its full significance. In addition, he trained a whole generation of U.S. physicists, who were greatly affected by his qualities of leadership and intellectual independence.
As a scientist, Millikan made numerous momentous discoveries, chiefly in the fields of electricity, optics, and molecular physics. His earliest major success was the accurate determination of the charge carried by an electron, using the elegant "falling-drop method"; he also proved that this quantity was a constant for all electrons (1910), thus demonstrating the atomic structure of electricity. Next, he verified experimentally Einstein's all-important photoelectric equation, and made the first direct photoelectric determination of Planck's constant h (1912-1915). In addition his studies of the Brownian movements in gases put an end to all opposition to the atomic and kinetic theories of matter.
Throughout Albert Einstein’s lifetime he accomplished many amazing things that have an effect on people today. For example, in 1905, “often called as Einstein’s “miracle year”, he published four papers in the Annalen der Physik, each of which would alter the course of modern physics” (Michio,Kaku 13). Throughout Einstein’s four books, he “applied the quantum theory to light in order to explain the photoelectric effect, offered the first experimental proof of the existence of atoms, laid out the mathematical theory of special relativity, and proved the first mechanism to explain the energy source of the Sun and other stars”(13). Throughout 1905-1915 Einstein began to realize that his theory for relativity was flawed, because “it made no mention of gravitation or acceleration” (19). “In November of 1915, Einstein finally completed the general theory of reality” (20); “in 1921 he won the Nobel Prize in Physics” (Belanger, Craig. 1).
Niels Bohr was a major contributor to modern physics. He won a Nobel Prize for his work on the atomic model. Also he came up with a way to furthermore define what a nucleus looks like, and also worked on the Quantum theory. He accomplished all of this while living in Copenhagen, Denmark and being a Jewish Chemist during World War II. Post-war he became a major contributor to his Open-World theory of helping Nations intelligence between each other about weapons of mass destruction.
Einstein's relativity theory revolutionized scientific thought with new conceptions of time, space, mass, motion, and gravitation. He treated matter and energy as exchangeable, not distinct. In so doing, he laid the basis for controlling the release of energy from the atom.
The Atomic Theory began in roughly 400BC with Democritus in Ancient Greece and is universally believed to be correct today. Democritus who was born in 460 BC and died 370 BC and is known as the father of modern science. Democritus proclaimed that everything is made up of atoms. He continued his theory to say that atoms will always be in motion, between atoms there is empty space, atoms are unbreakable, there are an infinite number of atoms all different sizes and shapes. He also said that iron atoms are solid and strong and have hooks to lock them together, water atoms are smooth and slippery, salt atoms have sharp jagged edges because of its taste and air atoms are light and spiralling.
The theory of quantum mechanics has divided the atom into a number of fundamental sub-atomic particles. Although the physicist has shown that the atom is not a solid indivisible object, he has not been able to find a particle which does possess those qualities. Talk of particles, though, is misleading because the word suggests a material object. This is not the intention for the use of the word in quantum physics. Quantum particles are, instead, representations of the actions and reactions of forces at the sub-atomic level. In fact, physicists are less concerned with the search for a material particle underlying all physical objects and more interested in explaining how nature works. Quantum theory is the means that enables the physicist to express those explanations in a scientific way.
Things are very different from each other, and can be broken down into small groups inside itself, which was then noticed early by people, and Greek thinkers, about 400BC. Which just happened to use words like "element', and `atom' to describe the many different parts and even the smallest parts of matter. These ideas were around for over 2000 years while ideas such as `Elements' of Earth, Fire, Air, and Water to explain `world stuff' came and went. Much later, Boyle, an experimenter like Galileo and Bacon, was influenced much by Democritus, Gassendi, and Descartes, which lent much important weight to the atomic theory of matter in the 1600s. Although it was Lavoisier who had divided the very few elements known in the 1700's into four different classes, and then John Dalton made atoms even more believable, telling everyone that the mass of an atom was it's most important property. Then in the early 1800's Dobereiner noted that the similar elements often had relative atomic masses, and DeChancourtois made a cylindrical table of elements to display the periodic reoccurrence of properties. Cannizaro then determined atomic weights for the 60 or so elements known in the 1860s, and then a table was arranged by Newlands, with the many elements given a serial number in order of their atomic weights, of course beginning with Hydrogen. That made it clear that "the eighth element, starting from a given one, is a kind of a repeat of the first", which Newlands called the Law of Octaves.
Stemming from the first years of the 20th century, quantum mechanics has had a monumental influence on modern science. First explored by Max Planck in the 1900s, Einstein modified and applied much of the research in this field. This begs the question, “how did Einstein contribute to the development and research of quantum mechanics?” Before studying how Einstein’s research contributed to the development of quantum mechanics, it is important to examine the origins of the science itself. Einstein took much of Planck’s experimental “quantum theory” research and applied it in usable ways to existing science. He also greatly contributed to the establishment of the base for quantum mechanics research today. Along with establishing base research in the field, Einstein’s discoveries have been modified and updated to apply to our more advanced understanding of this science today. Einstein greatly contributed to the foundation of quantum mechanics through his research, and his theories and discoveries remain relevant to science even today.
Michael Faraday is a British physicist and chemist, best known for his discoveries of electromagnetic induction and of the laws of electrolysis. He was born in 1791 to a poor family in London, Michael Faraday was extremely curious, questioning everything. He felt an urgent need to know more. At age 13, he became an errand boy for a bookbinding shop in London. He read every book that he bound, and decided that one day he would write a book of his own. He became interested in the concept of energy, specifically force. Because of his early reading and experiments with the idea of force, he was able to make important discoveries in electricity later in life. He eventually became a chemist and physicist.
Democritus was the leader of a group called Atomists. Although they were unable to prove that matter was made up of small particles, they were the first to come up with the idea. Democritus believed that atoms differed in size, shape, and movement but were all made of the same substances. Aristotle was the most important scientific philosopher in Greece. He believed that all matter on earth consisted of four pure substances or elements, which were earth, air, fire, and water. He also believed that the earth was the centre of the universe, and that anything beyond the earth consisted of a fifth pure substance called quintessence. Archimedes was an inventor and mathematician, who discovered several basic scientific principles and developed a number of measuring techniques. Ptolemy was an Egyptian astronomer. He developed a model for predicting the positions of the sun, moon, stars, and planets. Like Aristotle, he believed that the earth was the center of the universe. Between 400 AD. and 1000 AD.
Scientists from earlier times helped influence the discoveries that lead to the development of atomic energy. In the late 1800’s, Dalton created the Atomic Theory which explains atoms, elements and compounds (Henderson 1). This was important to the study of and understanding of atoms to future scientists. The Atomic Theory was a list of scientific laws regarding atoms and their potential abilities. Roentagen, used Dalton’s findings and discovered x-rays which could pass through solid objects (Henderson 1). Although he did not discover radiation from the x-rays, he did help lay the foundations for electromagnetic waves. Shortly after Roentagen’s findings, J.J. Thompson discovered the electron which was responsible for defining the atom’s characteristics (Henderson 2). The electron helped scientists uncover why an atom responds to reactions the way it does and how it received its “personality”. Dalton’s, Roentagen’s and Thompson’s findings helped guide other scientists to discovering the uses of atomic energy and reactions. Such applications were discovered in the early 1900’s by using Einstein’s equation, which stated that if a chain reaction occurred, cheap, reliable energy could b...