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400 BCE
Democritus
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- He lived from 460-370 BCE and was born in Thrance.
- He developed atomism, which is when atoms move and come in contact with other atoms, this forms bodies. The only properties of atoms are size, shape, and matter.
- Around 400 BCE he came out with the idea that we are made of small, hard, invisible particles called atoms -
384 BCE
Aristotle
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- He was born in 384 BCE Greece
- He created the logic and metaphysics branches of math and science
- He came up with the idea that the earth is composed of 5 elements: earth, fire, water, air, and aether
- He said that matter has features, but the features can not be matter themselves (for example, a cat can be grey but grey can not be a cat) -
700
Abu Musa Jabir Ibn Hayyan
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- He was born in 700 and lived in Iran
- He helped scientists understand nitric and sulfuric acid, his work was mainly focused on metals and acid
- He introduced the experimental method
- Broadened scope of materials used in investigating to include plant and animal substances -
1250
Albert Magnus
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- A Dominican priest whose goal was to show that theology and science could work together. He was highly criticized for this, saying he favored science too much.
- In 1250 he isolated arsenic, which made it the first element to be isolated and have a known discoverer -
1436
Printing Press
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- In 1436 the printing press was invented, allowing printed goods to become more widespread. This allowed the sharing of ideas in a mass wave of cultural diffusion. Scientific ideas could now be printed more often and with more ease than ever before. -
Robert Boyle
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- This Irish scientist invented combustion and respiration, making his scientific specialty gas
- He believed that elements were composed of smaller particles
- He is often called the father of modern chemistry, mainly due to his dedication -
Vacuum Tube
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- Invented in 1650, this helped scientists discover the effects of air pressure and the world around them. Even though there is still the same amount of volume between the two things, there is less matter there therefore the pressure pulling the objects together will increase. -
Electrostatic Generator
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- Invented in 1663 by Otto von Guericke, he was the first person to create an electrostatic generator. This invention consisted of a sulfur ball that rotated in a wooden cradle. This was the beginnings of mankind's relationship with electricity. -
Henry Cavendish
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- British scientist who discovered hydrogen but didn't name it, he just described it as flammable air
- He also discovered that water was composed of hydrogen and oxygen -
Antoine Lavoisier
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- French scientist, also considered father of modern chemistry
- Discovered and named oxygen and hydrogen, as well as that water was formed by them
- He explained the nature of combustion using experiments measuring oxygen in solids and liquids before and after burning them
- He helped organize the elements
- in 1775 he was part of the Royal Gunpowder Administration, helped improve gunpowder -
John Dalton
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- Born in 1766 England
- In 1805 he published his atomic theory along with information about his study of gases
- He studied the gases of the atmosphere, and through this study he discovered the idea of a physical structure for the atom
- He discovered that atoms need specific proportions to form a compound
- Atomic theory: matter is composed of physical particles called atoms. Atoms genetic makeup differ between elements -
Amedeo Avagodro
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- Italian scientist who developed the equation explaining that equal volumes of gases that are at the same temperature contain the same number of molecules, even if they are different elements in 1811
- Equation: (V/n)=k
- V: volume of the gas
- n: amount of substance of the gas
- k: proportionality constant -
Marie and Pierre Curie
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- French scientists who discovered radium and polonium
- They correctly interpreted radioactivity as a property of the atoms of radioactive substances. This view helped clarify the structures of the atoms
- These discoveries won two Nobel Prizes -
Dmitri Mendeleev
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- Russian scientist who was the primary creator of the first periodic table
- He organised it after recognizing patterns in the chemical properties. One pattern he noticed was the correlation between the mass of the atoms and the properties it held -
Lise Meitner
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- She was one of the first women scientists
-She was Austrian and Swedish, born in 1878
- She worked on both theoretical and experimental aspects of nuclear fission
- One of the first to realize the atomic nucleus can be split -
William Ramsey
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- A Scottish scientist who introduced noble gases to the periodic table
- In 1892 he became interested in why hydrogen was dense, and during experimenting he discovered argon and helium -
JJ Thomson
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- British scientist credited with the discovery of the electron and isotope, as well as the invention of mass spectrometer
- In 1897 he published articles on his findings. He conducted an experiment using cathode rays that were deflected in the presence of electrical field
- He continued to experiment through 1898 and 1899 -
Ernest Rutherford
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- Father of nuclear physics
- Proved that all the positive charge in the atomic nucleus came from something that took up 1/100,000 of the atom
- In 1909 he proved the Plum model of the atom was incorrect, made his own model
- Branched the study of atoms into nuclear physics and atomic physics
-To prove existence of nucleus, experimented by probing alpha particles through a piece of gold but 1/8000 deflected back, not what he expected -
Niels Bohr
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- Danish scientist who created Bohr model that showed electrons were not tightly packed together as previously thought
- His theory was that the electrons traveled in discrete orbits around the nucleus and that chemical properties are determined by the number of electrons in outer orbit
- Electrons can move between orbits using energy -
Chadwick
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- Born in 1891 England
- In 1920 he proposed the idea of a neutron to explain the phenomenon of hydrogen isotopes
- In 1932 he actually discovered the nucleus
- His discoveries, along with others, allowed scientists to make elements heavier than uranium in a lab and he helped discover nuclear fission -
Louis de Broglie
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- He was a French scientist who developed the theory of electron waves in 1924. He said that electrons must move around the nucleus -
Erwin Schrodinger
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- An Austrian-Irish scientist who created the equation for the shape on an electron wave, which creates the shape of an atom. He used the classical wave equation to develop his own equation -
Werner Heisenberg
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- This German scientist came up with the uncertainty principle in 1927: when you determine two paired quantities, there will always be a chance for error
- He created quantum mechanics, led to the discovery of allotropic forms of hydrogen
- Used Chadwick's neutron discovery to propose proton-neutron model of atomic nucleus
- May have been trying to slow down Germany's development of nuclear weapons during WW1 -
Irene Joliot-Curie
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- French scientist who, in 1933, discovered that radioactive elements can be artificially created from stable elements
- This discovery spurred research into radioisotopes and the practical applications of radio chemistry, especially in medicine -
Precision Scale
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- The scale has been around for thousands of years, the Egyptians care credited for creating them back in ancient times
- In the 1940s, there was a massive breakthrough when the scales could now measure down to 0.0005 g, allowing for more precise measurements. -
Linus Pauling
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- American scientist, in 1952 he decided he was going to figure out the structure of the nuclei
- Came up with nucleus clusters; deuteron, helion, and triton
- He didn't like the shell model so he came up with his own
- Even-even nuclei were made of clusters of alpha particles -
Rosalind Franklin
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- She was a British scientist who, through experimenting with x-rays, was able to find 2 forms of DNA. There was a "wet" A form and a "dry" B form.
- A photo of the DNA was given to competing scientists who took credit for her discovery
