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Period: Jan 1, 1400 to
Atomic Theory Timeline
Dates with asterisks (*) are historical events, not scientific events. -
Jan 1, 1440
Johannes Gutenburg Invents the Printing Press**
Beginning in 1936, finishing by 1940, Gutenburg built the first printing press. He revolutionized the production of books, making it faster and easier to share books, thus acting as a catalyst for the development of literature, the arts, and science. -
Oct 13, 1492
Discovery of the Americas**
Christopher Columbus leaves Spain with a fleet of ships attempting to find an all-water trade route to Asia. Instead, Columbus lands in the "New World" believing he found Asia. -
Jan 1, 1517
Reformation of the Catholic Church**
The Catholic Reformation was the antagonizing force against Protestantism in the early 1500's. The Catholic church had failed to reform during the Renaissance, making it appear outdated. People wanted a religion of more spiritual influence as opposed to worldly influence. -
Galileo Convicted of Heresy**
The Holy Office of the Catholic Church did not agree with Galileo's teachings that contradicted what the church itself had been teaching. The church believed in Copernicus's geocentric theory- the earth is immobile while the sun revolves around it. Galileo, on the other hand, recently proposed his heliocentric theory- the sun is stationary while the earth and all other planets revolve around it. The church arrested Galileo because he refused to discontinue his new teachings of the sun and earth. -
Joseph Priestley Discovers Oxygen, Carbon Monoxide, and Nitrogen Dioxide
In a series of experiments, Priestley discovers that "air is not an elementary substance, but a mixture," and goes on to explain that among that mixture of gas is a gas he calls "dephlogisticated air," which will later be renamed "oxygen." -
Antoine Lavoisier Writes the Law of Conservation of Mass
Lavoisier, now known as "the Father of Modern Chemistry," believed that mass was conserved through the course of chemical reactions, thus stating that the mass of the products equals the mass of the reactants in a reaction. -
Adoption of the Declaration of Independence**
The Second Continental Congress adopts this document as proof that the original 13 colonies have declared their independence from Great Britain, while providing explanation and justification for such action. -
Alessandro Volta Creates Electrochemical Cells and Batteries
Volta builds the first "pile," or battery, by using alternating disks of two different kinds of metals separated by disks of carboard soaked in acidic or salty solutions. This became the basis of the mordern-day wet cell battery. -
John Dalton Formulates the Atomic Theory
Dalton wrote his idea based on the knowledge that atoms can be determined by their weight. He proposed his atomic theory to the Royal Instituation in 1803, stating these basic ideas:
All matter is composed of atoms.
Atoms cannot be created nor destroyed.
All atoms of the same element are identical.
Different elements have different types of atoms.
Chemical reactions occur when atoms are rearranged.
Compounds are formed from atoms of the constituent elements. -
Louis Pasteur Creates the Pasteurization Process
Pasteur continued his research and work with microbiological techniques and created the pasteurization process. This process was intended to keep fermentable liquids (such as wine and beer) from spoiling by using special heating treatments. -
Civil War Begins**
Southern states seeked a succession from the North because they no longer wanted to abide by the same laws as the North, mostly reguarding slavery. The South became known as the Confederacy and the North became known as the Union. -
Civil War Ends**
Robert E. Lee surrendered the last major Confederate army to Ulysses S. Grant at the Appomattox Courthouse on April 9, 1865. The last battle of the Civil War was fought at Palitmo Beach, Texas on May 13, 1985. -
Alfred Nobel Creates Dynamite and the Nobel Peace Prize
Nobel experimented with nitroclycerine and its additives to perfect his creation of dynamite. He also created a detinator/blasting cap so it was easier to set off. He patented this project in 1867. Nobel's good friend Bertha von Suttner, who wrote "Lay Down Your Arms" during the Arms Race, became a prominant figure of the peace movement. In his will, Nobel left a prize for any person or organization promoting peace, which was awarded to Suttner by the Norwegian Storting after Nobel's death. -
Completion of the First Transcontinental Railroad in the USA**
The Pacific Railroad Act of 1862 chartered the Central Pacific Railroad Company and the Union Pacific Railroad Company with the task of building a railroad that goes from the west (Sacramento, California) to the east (Omaha, Nebraska), with each company starting on either side, building toward the middle. The railroad was completed on May 10, 1869 when the two companies met in Promontory, Utah. -
Eugene Goldstein Studies Cathode Rays and Anode Rays
Goldstein named Johann Hittorf's discovery, the negatively-charged electrons that are emitted when an electric current is forced through a vacuum tube, "cathode rays." He continued to observe how cathode rays interracted with his new discovery, anode rays (or "canal rays"- positively-charged particles that are formed when electrons are removed from gas particles in a cathode ray tube). His work led to the discovery of the proton by Ernest Rutherford. -
Guglielmo Marconi Sends First Radio Signal
Marconi sent and received his first radio signal in Italy in 1895. By 1899, he sent his first radio signal across the English Channel. Two years later, Marconi receives a telegram bearing the letter "S," coming from England to Newfoundland, being the first successful transatlantic radiotelegraph. -
Henri Becquerel Discovers Radioactivity
Bacquerel won the Nobel Peace Prize in Physics for his discovery of natural radioactivity, which is only part of the larger topic of scientific investigations of the electromagnetic spectrum and the latter discovery of x-rays. -
JJ Thomson Develops the "Plum Pudding Model"
The Plum Pudding Model is an atomic diagram proposed by Thomson in 1897. It is also referred to as the Chocolate Chip Cookie Model or the Blueberry Muffin Model because the model resembles those types of treats, in which the "pudding" itself is positively charged and the "plums" are the randomly dispersed negatively charged electrons. -
Marie Curie Discovers the Radioactive Elements Radium and Polonium
Working with her husband Pierre, Curie discovered two radioactive elements by chemically extracting them from pitchblende ore. They furthered their research by studying the x-rays that each element emits. She later found that the harmful properties of x-rays can kill tumors. -
Max Planck Develops the Quantum Theory
Planck revolutionized modern physics when he explained how light must be emitted and absorbed in discrete amounts, as opposed to popular belief that light was just one long, continuous electromagnetic wave.
Quantum Theory- A theory of matter and energy based on the concept of quanta, especially pertaining to quantum mechanics. -
Robert Millikan Determines Mass and Charge of Atoms
In the University of Chicago, Millikan performed his famous oil-drop experiment in which he measured the electric charge on falling droplets of water and oil. This helped him discover that any given droplet has a charge of a multiple of a definite fundemental value, which is the charge of the electron. This allowed for determining the mass of the electron and the positively charged atom. -
Albert Einstein Writes Theory of Relativity
Einstein published his Special Theory of Relativity, regarding gravitational phenomena, in 1905. This led to his General Theory of Relativity. In the same year, Einstein wrote his famous equation "E=mc^2" which translates into "energy equals mass times the velocity of light squared." -
Ernest Rutherford Conducts Gold Foil Experiment
After conducting his famous gold foil experiment (in which he fired radioactive particles though very thin sheets of various metals (preferrably gold) and detecting that most of them passed through by using screens coated with zinc sufide), Rutherford concludes that most of the atom's mass is located in it's positive nucleus while the rest of it is mostly empty space disrupted by the occasional orbitting negative electron. -
Neils Bohr Creates the Bohr Atom Model
Bohr applies the quantum theory to Rutherford's atomic structure by assuming that electrons travel in stationary orbits. This led to the calculation of possible energy levels and the light that is emitted when electrons switch between said energy levels.
Bohr Model- The given element's atomic symbol in the center of the diagram. The electrons are placed in specific energy levels (lowest energy level=smallest, innermost ring on diagram) depending on how many electrons each energy level can fit. -
Henry Moseley Rearranges Periodic Table
Moseley discovered that each element's energy from x-rays increases in a linear fashion with each progressive move up the periodic table. He states that this relationship is caused by the function of the positive charge of the nucleus. Moseley took this into consideration while rearranging the periodic table by atomic number as opposed to atomic mass. This left holes in to table for elements that would later be discovered. -
Assassination of Archduke Ferdinand**
On this day, Archduke Ferdinand and his wife Sofia are shot to death by a Bosnian Serb while on their official visit to the Bosnian capital of Sarajevo. This event was the beginning of a chain reaction of events resulting in World War I starting in August of 1914. -
Bolshevik Revolution**
Beginning in early October of 1917, Lenin convinced the entire Bolshevik party to revolt against the Provisional government in Russia. Armed workers known as Red Guards and other revolutionary groups worked under the control of the Soviet's Military Revolutionary Committee. Thousands of Red Guards stormed the Winter Palace, thus conquering the Provisional Government. -
Signing of the Treaty of Versailles**
The treaty was a peace settlement resulting from the devastation caused by the now-ended World War I. It was signed by Germany and the Allied Powers at the Palace of Versailles on June 28, 1919. -
Sir Frederick Banting Isolates Insulin
Banting worked with his assistant Charles Best to isolate the pancreatic diabetes-preventing hormone insulin, which led to lifesaving treatments for diabetic people. His work included ligating a dog's panceas, then removing it, slicing it and freezing the slices in a mixture of water and salts. With the slices half frozen, they were ground up, filtered, and injected into the bloodstream of the now-diabetic dog. With a few daily treatments of this "insletin" the dog kept healthy and symptom-free. -
Louis deBroglie Explains Wave-like Nature of Electrons
DeBroglie introduced his theory of particle-wave duality in early 1924. He spoke against popular belief, stating that particles can behave as waves and waves (radiation) can behave as particles. This theory explained why atoms, molecules, and protons behave the way they do. -
Erwin Schrodinger Writes Schrodinger's Wave Equation
Schrodinger's Wave is a mathematical equation of wave mechanics and is still the most-used equation in modern quantum theory. Schrodinger predicted how electrons behave within a hydrogen atom using this equation. He furthered his work by experimenting with analytical mechanics, color theory, radiation theory, etc. -
Philo Farnsworth Invents the Television
At age 21, Farnsworth produced the first television transmission. By taking a glass slide, smoking it with carbon, scratching a line into it, placing it into a carbon arc projector, and shining it onto a photocathode, he created the first camera tube. He used his wife Pem as a subject for televising. -
Werner Heisenberg Writes the Uncertainty Principle
Also known as the Principle of Undeterminacy, Heisenberg explains his what Uncertainty Principle proves: "The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa." -Heisenberg, uncertainty paper, 1927 -
James Chadwick Discovers the Neutron
Chadwick discovers the neutron, a fundemental part of an atom with no electrical charge, while working under Ernest Rutherford at Cambridge. Being one of the most important discoveries of the thewntieth century, it solved the puzzle of the atom. Continuing his work with neutrons, Chadwick's results led to the discovery of nuclear fission and the latter development of nuclear weapons and nuclear power production. -
Wallace Carothers Discovers Neoprene and Nylon
Elmer Bolton recruited Carothers to find a synthetic substitute for natural rubber. Arnold Collins isolated a liquid compound, chloroprene, which spontaneously polymerized into a rubberlike solid called "neoprene." After renewing his work in early 1934, Carothers and his group made a discovery of a polyamide fiber called "nylon." -
Bombing of Pearl Harbor**
At 6:00am, six Japanese carriers sent the first flight of 181 planes composed of torpedo bombers, dive bombers, horizontal bombers, and fighters to Oahu, Hawaii's Pearl Harbor. After they hit shortly prior to 8:00am and finished roughly two hours later, 21 American fleet ships and been either sunken or damaged. 188 aircrafts were destroyed and another 159 were damaged. 2,403 Americans died. This led to America joining the Allied war effort against Japan and the other Axis Powers in World War II. -
Leo Szilard Creates the First Nuclear Chain Reaction
After many years of work since 1933, Szilard finally created the first controlled nuclear chain reaction (aka nuclear explosion) on December 2, 1942. He described it as "a neutron-induced series of chain reactions to create explosions." This discovery soon led to the development of the first atomic bomb. -
Initial Concept for the World Wide Web (Internet)**
The initial concept of the internet was to find a way to simply obtain and relay quality information without delay by electronic means. Leonard Kleinrock developed the theory of packet switching to form the basis of internet connections. -
Creation of the First Cellular Phone**
Martin Cooper developed the first cell phone, a Motorola DynaTAC, and made the first public phone call in 1973. The battery life was only about 20 minutes and it weighed as much as eight iPhones. -
Kary Mullis Creates the First Polymerase Chain Reaction
Mullis stumbed upon polymerase chain reactions while working with a group of scientists since Spring of 1983 trying to find methods of identifying mutations in human genomic DNA as a part of a DNA diagnostics group at Cetus. He made his first publication about PCR in 1985 when he published a description of how PCR was used for detecting the mutation causing sickle cell anemia in whole genomic DNA.
