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A war began between Athens and the Island of Samos. The Samos people lost after Athens besieged them.
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He formulated the atomic theory of the universe. He had coined the term “atomos” or “atom”, and reasoned that all matter is made of atoms. They have existed forever and are in constant motion within a void or vacuum -
His atomic theory contained these main points:
Elements are made of extremely small particles called atoms.
Atoms of a given element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.
Atoms cannot be subdivided, created, or destroyed.
Atoms of different elements combine in simple whole-number ratios to form chemical compounds.
In chemical reactions, atoms are combined, separated, or rearranged. -
John Dalton simplified the atom. His model showed a table of atomic weights containing 6 elements; Hydrogen, Oxygen, Nitrogen, Carbon, Sulfur, and Phosphorus. -
The United States declared was on England on 18 June 1812. It was one of the only wars fought on American soil.
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Faraday established the two laws of electrolysis in 1834. These two laws stated that atoms have an electrical component, which shows that electricity can cause chemical reactions at the atomic level. -
Eugen Goldstein discovered Anode rays in gas forms. An anode ray is a beam of positively charged ions created by certain types of gas discharge tubes. This proves that atoms contain positively charged particles. -
This was a very important event for the city of Paris. It attracted more than 30 million visitors and the main event for the fair, which still exists today, was the Eiffel Tower.
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The Plum Pudding model was created by J. J. Thompson in 1904, which followed his discovery of the electron in 1897. The model described the atom as a sphere of positive charge with negatively charged electrons embedded within. However, it was rendered obsolete by Ernest Rutherford’s discovery of the Atomic nucleus in 1911. -
Rutherford is responsible for the discovery of the atomic nucleus. This debunked J. J Thompson’s “Plum Pudding Model” and proved that atoms have an orbit and a positively charged nucleus at the center. The resulting model was known as the “nuclear” model. -
Robert Millikan used the oil drop experiment, which involves suspending charged oil droplets in an electric field. He observed that the electric charge on an oil droplet was always a multiple of a single value. He called this the elementary charge. He proved that protons and electrons had positive and negative charges. For the significance of the experiment, he was awarded the Nobel Prize in Physics in 1923. -
World War 1 began in July of 1914. Many modern technological advancements were developed during the war. These included the first use of tanks, planes, machine guns, and chemical weapons. -
The solar system model is an obsolete model of an atom. It was made by Neils Bohr to build on Ernest Rutherford’s nuclear model. -
The model showed that electrons existed on a 3 dimensional space instead of fixed orbits. The model uses probability to show electrons as a “cloud” of probability. The density of the cloud indicates the likelihood of finding an electron in that area. The model was significant because it provided a more accurate depiction of atomic behavior. -
The uncertainty principle states that there is a limit to how precisely you can know certain pairs and properties of a particle, such as it’s position and momentum. The uncertainty principle causes the model to describe the electron’s locations in a cloud, not in a precise path. Orbitals describe the 3 dimensional region where an electron is most likely to be found. -
James Chadwick’s updated model stated that the nucleus contained both protons and neutrons, with electrons orbiting on the outside. It showed how neutrons fit into an atomic model. -
The Spanish Civil War was fought from 1936 - 1939 between the Republicans and Nationalists. The opposing nationalists established the spanish state against the fascist republicans allied with Italy and Nazi Germany. -
The United States Navy defeated the Japanese fleet at the Battle of Midway in 1942. It was one of the first battles that aircraft carriers were utilized.