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400 BCE
Democritus
Democritus believed that all matter consisted of tiny invisible particles. He tested this theory by taking a simple seashell and breaking it in half. He then took that half and broke it in over again until it was powder. He then took the smallest piece and tried to put it back together but he could not. So, he discovered that the invisible block of life is the atom. He then later theorized that the tiny particles somehow have hooks on them attached to them, so they can stick together. -
Period: 460 to
History of the Atom
This timeline shows when each of these scientists contributed to our current understanding of the atom. -
Antoine Lavoisier
Lavoisier was born August 26, 1743 in Paris, France. Lavoisier influenced the atomic theory the most coming up with the law that states matter cannot be created or destroyed. The Law of Conservation. He was also known for the great experiments he would do daily. He turned HgO into Hg + O. He died May 8, 1794 from execution by guillotine. -
John Dalton
John was born on September 6, 1776 in the UK. Dalton did many good things for the world during his life like contributing to color blindness and adding to the atomic theory. He said that all matter is made up of atoms and have all different size and elements. He wrote many books explaining his theory. He died on July 2, 1844. -
J.J. Thomson
Sir Joseph John Thomson or J.J. Thomas was born on December 18, 1856. He added to the Atomic Theory that there was an electron, he performed a series of experiments in 1897 designed to study the nature of the electron discharge in a high vacuum cathode ray - tube, an area being investigated by many scientist at the time. (Plum Pudding Model) -
Marie Curie
Curie was born November 7, 1867. Her and her husband led to the discovery of polonium and radium and after her husband’s death the X-rays were developed. They discovered radiation in their research of pitchblende. She is the first woman to win a Nobel Prize and ever to win one in chemistry and physics. She later died on July 4, 1934 from exposure to radiation. -
Niels Bohr
Bohr was born October 7, 1885. He was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element. He created the Bohr model. He died November 18, 1962 from congestive heart failure. -
Albert Einstein
Einstein was born March 14, 1879 in Germany. He was the first person to show that atoms exist by using a simple microscope and many other great things. He died on April 18, 1955 caused by Abdominal aortic aneurysm. -
Max Planck
Max was born on April 23, 1858. He contributed to the Atomic Theory by originating the quantum theory. Which is science dealing with the behaviour of matter and light on the atomic and subatomic scale. He died October 4, 1947. -
Robert Millikan
He was born March 22, 1868 in Morrison IL. He is best known for measuring the charges of the electron. Which he will win a Nobel Prize in Physics in 1923. He died on December 19,1953. -
Werner Heisenberg
Born December 5, 1901. He discovered that allotropic form hydrogen . He based it all off of quantum theory used for interpreting the behaviour of elementary particles and atoms. He died on February 1, 1976. -
Ernest Rutherford
Rutherford was born on August 30, 1871 in Nelson, New Zealand. The fourth child of twelve. He was the one that discovered the nucleus by designing an experiment to use alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure. He received the Nobel Prize in 1908. He died on October 8, 1937 from strangulated hernia. -
Louis De Broglie
Born August 15, 1892 in France. In 1924, he discovered the wave nature of electrons and suggested that all matter have wavelength properties. Most of Broglie’s work included X- rays. The experiments demonstrated the wave nature of matter and completed the wave particle duality. He died on March 19, 1987 from natural causes. -
James Chadwick
Chadwick was born October 20, 1891. He made the discovery of the neutrons in 1932. Also winning a Nobel Prize. He was using scattering data to calculate the mass of his neutral particle. He died on July 24, 1974. Not so fun fact he was a POW (prisoner of war) during WWl. -
Erwin Schrodinger
Erwin was born August 12, 1887. He discovered the equation for electron movements in 1933 he won a Nobel Prize in Physics. He did a lot of experiments by drawing them out. He died January 4, 1961 from tuberculosis. -
Louis De Broglie
Born August 15, 1892 in France. In 1924, he discovered the wave nature of electrons and suggested that all matter have wavelength properties. Most of Broglie’s work included X- rays. The experiments demonstrated the wave nature of matter and completed the wave particle duality. He died on March 19, 1987 from natural causes.
