Old Dudes Timeline Project

Democritus

465 BCE

Along with his teacher Leucippus, Democritus helped develop the atomic theory. They theorized that if a sample of matter was cut into half enough times that it would eventually get so small that you would not be able to cut it in half anymore. Today he is credited as being one of the founders of modern science due to his contributions.

Medieval Alchemy

Jul 1, 1500

Alchemy is a reflection of religions prominent in Chinese, Hindu, Arabic and European cultures. Alchemists believed that matter consisted of four elements: water, earth, air, and fire. In the early 1500’s Philippus Paracelsus thought that the distinctive qualities of metal where obtained from mercury, sulfur and salt. Alchemists’ theories gave rise to modern chemical developments.

John Dalton Publishes "A New System of Chemical Philosophy"

Dec 1, 1808

John Dalton proposed an atomic theory of matter which stated:
1. All matter is composed of atoms which can’t be created, destroyed or broken down.
2. Atoms of one element are all identical to each other and different from other elements.
3. Atoms combine in different ratios to form compounds.
4. Atoms can be separated, rearranged and recombined to form new compounds.

Marie and Pierre Curie Win Nobel Prize

Dec 10, 1903

Marie and Pierre Curie were the people who discovered the concept of radiation and that some elements gave off radiation. They theorized that radiation is linked to the interior of the atom itself and this discovery revolutionized chemistry. They also discovered two new elements, polonium and radium, in 1898. In 1903, they won half the Nobel Prize in physics. The other half went to Henri Becquerel for his discovery of spontaneous radioactivity.

Henri Becquerel Wins Nobel Prize

Dec 10, 1903

Henri Becquerel was awarded half the Nobel Prize in Physics in 1903 for his discovery of spontaneous radioactivity. He discovered that uranium emitted these rays and that they differed from x-rays in that they could be deflected by an magnetic or electric field.

JJ Thompson and Corpuscles

Dec 10, 1906

Thomson determined the ratio of the particle’s charge to its mass, which he felt was a fundamental part of all atoms by experimenting with cathode-ray tubes. The rays were actually negatively charged particles called “corpuscles” which would later be known as electrons. Later he used hydrogen gas to the modified cathode-ray tube and concluded that the atom resembled a “spongy ball” or “plum pudding” where negative electrons are disturbed in a positively charged spongy mass.

Ernest Rutherford Wins Nobel Prize

Dec 10, 1908

Ernest Rutherford wins the Nobel Prize in Chemistry "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances". In 1899, he proved that there were two types of radiation: alpha and beta. This lead to the theory that elements could disintegrate and be transformed into other elements.

Neils Bohr Wins Noble Prize

Dec 10, 1913

In 1913, Neils Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain shells, electrons move around the nucleus but only in accepted in allowed orbits He later won a noble prize for his investigation of the structure of the atoms and the radiation emanating from them.

James Chadwick Wins Nobel Prize

Dec 10, 1935

James Chadwick was awarded the Nobel Prize in Physics in 1935 for discovering the neutron. He was able to prove their existence, which paved the way for future science, including the creation of the atomic bomb and the fission of uranium 235.