Atomic History Mini Project by Omar Jackson Jr

Democritus 400BC

28ojackson — 2025-09-12 17:03:42 UTC

Democritus believed that matter was made of small particles called atoms that cannot be broken down. No one believed Democritus because no one had seen these so-called "atoms" but they believed Artistotle because of the 4 elements he believed in that could be proven to be true.

Aristotle 400 BC

28ojackson — 2025-09-12 17:09:36 UTC

Aristotle believed that all matter was made of 4 elements: Earth, Air, Fire and Water. People believed him because he was able to prove his hypothesis about all matter.

John Dalton 1809

28ojackson — 2025-09-12 17:12:24 UTC

In 1809, modern atomic theory was developed by an English Scientist who went by the name of John Dalton. His theories were based on observations and experiments which made him come to various conclusions like matter is made of small particles or atoms, atoms cannot be created nor destroyed, but mainly he believed atoms were small solid particles.

J.J Thomson 1897

28ojackson — 2025-09-12 17:23:30 UTC

An English Physicist named J.J Thomson did experiments to determine the parts that make up the atom in 1897. He decided to use a cathode ray tube and also a vacuum tube where all the air had been pumped out and a limited amount of other gases pumped in. His experiment involved a electric current passing through a voltage source which made a beam appear to move from the negative and to the positive end.

Ernest Rutherford 1910

28ojackson — 2025-09-12 17:25:02 UTC

In 1910, an English Physicist named Ernest Rutherford continued J.J's Thomson's work. He believed the plum pudding model was correct, but wanted to discover the size of atoms. To find that out, Rutherford conducted the "Gold Foil Experiment" where he used thin gold Foil sheets and radioactive material which made the material release alpha particles and glow when in contact with the fluorescent screen.

Niels Bohr 1913

28ojackson — 2025-09-12 17:32:09 UTC

1913, The next model of the atom came from a Danish chemist, Niels Bohr. In this model the protons are located in the nucleus and the electrons are located in pathways around the nucleus.

Erwin Schrodinger/ Werner Heisenberg

28ojackson — 2025-09-12 17:35:15 UTC

In 1926, The wave mechanical or electron cloud model was introduced by Schrodinger and Heisenburg. In this model the electrons do not follow a set path, but they have wiggle room. Because of that, you could not predict the location of an electron at a given time.

James Chadwick

28ojackson — 2025-09-12 17:37:26 UTC

In 1932, the man who discovered the last subatomic particles was none other than James Chadwick. The neutron involved was so difficult to find because it does not have a charge, it is neutral. Chadwick's discovery earned him the famous nickname: Jimmy Neutron.

In 1932, The Revenue Act was enacted, creating the first gas tax in the United States.

28ojackson — 2025-09-12 17:45:06 UTC

In 400 BC, The Egyptians successfully revolt against Persian rule

28ojackson — 2025-09-12 17:46:06 UTC

In 1877, Rutherford B. Hayes was sworn in as the 19th president of the United States

28ojackson — 2025-09-12 17:46:43 UTC