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Mendeleev's Periodic table
Mendeleev had written the properties of elements on pieces of card and tradition has it that after organising the cards while playing patience he suddenly realised that by arranging the element cards in order of increasing atomic weight that certain types of element regularly occurred. For example a reactive non-metal was directly followed by a very reactive light metal, then a less reactive light metal. -
Civil War Begins
In the year 1860, the bloodiest battles in U.S. history begun. The war was between the Union North and the Confederate South. Around this time Dmitri Mendeleev made his Period Table of Elements. The civil war lasted for almost exactly four years. When South Carolina seceded, it instigated a war and that is when the times became really bad for the United States. Civil War Video : (https://www.civilwar.org/learn/videos/soldier-life-during-civil-war) -
Gettysburg Address
The Gettysburg Address was a short speech given on November, 19, 1863 by President Abraham Lincoln at the dedication of the National Cemetery at Gettysburg, Pennsylvania. The Gettysburg Address was delivered in the height of the American Civil War to commemorate the massive numbers of deaths and casualties at the bloody Battle of Gettysburg that was fought July 1st through 3rd, 1863. -
Law of octaves
Law of octaves, the generalization made by the English chemist J.A.R. Newlands in 1865 that, if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements. Newlands was one of the first to detect a periodic pattern in the properties of the elements and anticipated later developments of the periodic law. -
President Lincolns Assassination
At 10:15, Booth slipped into the box and fired his .44-caliber single-shot derringer pistol into the back of Lincoln’s head. This effected the reconstruction after the civil war because a southern man killed a northern president. This was a pivotal part in history because he was the first president to be assassinated. -
Andrew Johnson Impeached
The United States President after Lincoln, President Andrew Johnson, was the first President impeached in 1868. He was impeached by the house and the Senate. Congress made the Tenure of Office Act on purpose because they new Johnson would violate it, so they could legally impeach him. Congress's plan worked, Johnson was impeached on February 24th, 1868. -
Discovery of Electron
J. J. Thomson constructed a glass tube which was partially evacuated i.e. much of the air was pumped out of the tube. Then he applied a high electrical voltage between two electrodes at either end of the tube. He detected that a stream of particle was coming out from the negatively charged electrode to positively charged electrode. -
Spanish American War
On February 15, 1898, a mysterious explosion sank the battleship USS Maine in Havana Harbor, triggering a war between the United States and Spain. The Maine had come to Cuba to protect American citizens while Cuban revolutionaries were fighting to win independence from Spain. The United States supported their cause, and after the Maine exploded, demanded that Spain give Cuba freedom. Instead, Spain declared war. -
plum pudding model
The Plum Pudding Model is a model of atomic structure proposed by J.J. Thomson in the late 19th century. Thomson had discovered that atoms are composite objects, made of pieces with positive and negative charge, and that the negatively charged electrons within the atom were very small compared to the entire atom. Video Link (https://www.youtube.com/watch?v=dehxVQAUqBs) -
San Francisco Earthquake
The city of San Francisco was rocked by a violent earthquake in 1906. The devastating San Francisco earthquake was followed by a terrifying firestorm. The 1906 San Francisco earthquake and subsequent fire remains one of the most devastating natural disasters to have hit America. The death toll was very high, somewhere around 3000 people. -
Moseley's atom numbers
Today, we know that the atomic number gives the number of protons (positive charges) in the nucleus. This was the discovery made by Henry Gwyn-Jefferies Moseley. He found that certain lines in the X-ray spectrum of each element moved the same amount each time you increased the atomic number by one. -
Rutherford"s Gold Foil Experiment
Physicist Ernest Rutherford established the nuclear theory of the atom with his gold-foil experiment. When he shot a beam of alpha particles at a sheet of gold foil, a few of the particles were deflected. He concluded that a tiny, dense nucleus was causing the deflections. -
Titanic
On the night of 14 April 1912, a ship from Southampton to New York, the RMS Titanic, struck the iceberg that would ultimately lead to the sinking of the ship. On this massive ship there were 2,223 passengs, none survived the accident. Before the crash the Titanic was given 6 warnings of icebergs, before the collision. -
Bohr"s Planetary modle of the atom
In atomic physics, the Rutherford–Bohr model or Bohr model or Bohr diagram, introduced by Niels Bohr and Ernest Rutherford in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar to structure of the Solar System -
World War One
What started out as a local European war soon became a global war that lasted from 1914-1918. World War I was the first war that involved nations (28 to be exact) from around the world, and is commonly called The Great War or The War to End All Wars. World War One was a war that brought out a lot of technological advancements, because of war and the drive to win. -
discovering the proton
After the discovery of the electron, it was realized that there must be positive charge centers within the atom to balance the negative electrons and create electrically neutral atoms. Rutherford's discovery of the nucleus demonstrated that these positive charges were concentrated in a very small fraction of the atoms' volume.The term proton itself seems to have been coined by Rutherford, and first appears in print in 1920. -
Schrodinger Equation
Schrodinger was the first person to write down such a wave equation. Much discussion then centred on what the equation meant. The eigenvalues of the wave equation were shown to be equal to the energy levels of the quantum mechanical system, and the best test of the equation was when it was used to solve for the energy levels of the Hydrogen atom, and the energy levels were found to be in accord with Rydberg's Law. -
The Great Depression
The Great Depression was the worst economic downturn in the history of the industrialized world. It began after the stock market crash of October 1929, which sent Wall Street into a panic and wiped out millions of investors. Over the next several years, consumer spending and investment dropped, causing steep declines in industrial output and employment as failing companies laid off workers. -
Discovery of Neutron
The 5.3 MeV energy of the ejected protons could be easily explained if the neutral particle had a mass comparable to that of the proton. For headon collisions, this would require only 5.3 MeV from the neutral particle, a value in the range of observed nuclear particle emissions.Not only were these inconsistent with photon emission on energy grounds, the cross-section for the interactions was orders of magnitude greater than that for Compton scattering by photons. -
Beginning of World War Two
World War 2, also known as the Second World War, was a war fought from 1939 to 1945 in Europe and, during much of the 1930s and 1940s, in Asia. It was the Axis forces against the Allied Forces of the world. The war ravaged civilians more severely than any previous conflict and served as a backdrop for genocidal killings by Nazi Germany. World War Two lasted for almost 5 years and was one of the most brutal wars in history.
