Chemistry

Democritus

460 BCE

Greek philosopher known as the father of modern science, he formulated an atomic theory of the universe. Which states everything is made up of atomos and they will always be in motion.

Atomos and Atoms

460 BCE

Atomos: that which cannot be cut. Atom: the smallest unit of matter which still retains the identity and properties of that matter.

Aristotle

384 BCE

Greek philosopher who opposed Democritus’s atomic theory by believing in their only being 4 elements which were: Earth, Air, Fire, and Water. He believed the 4 elements were mixed together in differing amounts to make up everything. Aristotle was very popular and many people believed in his 4 elements theory which would cause incorrect science conclusions for the next 2000 years.

Alchemy

300 BCE

Alchemy comes from the Greek Khemia word for Egypt which was conquered by Alexander the Great. The Greek philosophy of Earth, Air, Fire, and Water making up all matter in the world would be merged with the Egyptian religion. Scientists and philosophers would continue to learn and discover new findings and spread their finding West to Spain. Where Alchemists would split up into 2 very different groups by the 16th Century.

Western European Alchemists

1600

Alchemists in Western Europe focused their study on finding new compounds, reactions, and chemical processes. These alchemists were creating the study of Chemistry. Many discoveries were made in this time period like distillation.

All Other European Alchemists

1600

All other alchemists studied a more spiritual and metaphysical side of alchemy. They were trying to discover the Philosophers Stone to be able to turn any base metal into any other metal like gold. They were also searching for spiritual purification which would come with immortality.

All Other European Alchemists Theories

1601

Vitalism: all living things have a “vital spirit” which makes them living and without it the object is inanimate.
The Phlogiston Theory: Was first stated by Johann Joachim Becher in 1667. The word Phlogiston comes from the Ancient Greek word phlogistón which means “burning up”. The theory states the any object that is flammable is partially made up of a fire element making the object combustible. Also carbon dioxide was named as “dephlogisticated air” meaning that air could no longer burn.

Benjamin Franklin

1752

Franklin was able to discover that electrical charges come in both positive and negative charges. He also learned that opposite charges attract and same charges repel. Benjamin Franklin is also known for attaching a key to a kite and flying it during a thunderstorm as one of his experiments with electricity.

Joseph Louis Proust

1754

Proust discovered The Law of Definite Proportions stating all chemical compounds contain exactly the same proportions of elements by mass.

Anton Laurent de La Voisier

1794

Voisier is known as the Father of Modern Chemistry for debunking the Phlogiston Theory by proving that Oxygen causes combustion, discovering the Law of Conservation of Mass, and discovering matter can change form, and can’t be created or destroyed in a chemical reaction. Voisier made many discoveries in the chemistry field until he was beheaded in 1794 during the French Revolution.

John Dalton

1800

Dalton was an English chemist who is considered as the Father of Atomic Theory for his Atomic Theory of Matter. His theory states that all matter is made up of atoms which are indestructible and invisible, all atoms of elements are identical, atoms of different elements have different weights and chemical properties, atoms of different elements combine in whole numbers to create compounds, and atoms can’t be destroyed or created.

William Crookes

1875

Crookes created a tube that was painted with fluorescent paint that is absent of air and matter within the tube. When the tube is powered by a battery the paint glows indicating the presence of radiation. When Crookes add a wheel inside the Cathode Ray Tube the wheel began spinning indicating that the Cathode Ray has mass.

Sir John Joseph Thomson

1898

Thompson took charged plates and used them to effect the cathode ray. He witnessed the ray deflect away from the negative plate meaning the ray was made of negative particles, which he would name as electrons. He would also create a diagram of what he believed the atom looked like.

Ernest Rutherford (Part 2)

1900

Ernest also discovered Atoms are mostly empty space, there must be a solid core in the center of the atom, and the core must be positively charged, since it deflected an alpha ray.

Ernest Rutherford

1900

Rutherford identified both alpha and beta radiation. He saw a correlation between alpha radiation and helium, this would help him eventually identifying a helium nucleus. He also saw a correlation between beta radiation being electrons. Ernest would make the gold foil experiment famous which consists of aiming a ray of alpha radiation at the gold foil and seeing the light.

Antoine Henri Becquerel

1903

Discovered the radioactivity of the Uranium Ore.

Curies (Marie and Pierre)

1903

Discovered and isolated polonium and radium from uranium ores. This would win them the Nobel Prize for physics.

Robert Andrews Millikan

1910

Calculated the mass and charge of an electron which would eventually win him a Nobel Prize.

James Chadwick

1935

Proved the existence of another subatomic particle, that had no charge, named it the neutron.