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600 BCE
Alchemy
-Developed the theory that all metals are composed of mercury and sulfur and that it is possible to change base metals into gold.
-The ancient Chinese were performing Alchemy as early as 500 B.C. -
500 BCE
Leucippus
-Leucippus is considered the originator of the theory of atomism.
-In philosophy, atomism refers to the theory that indivisible particles combine in different arrangements to compose everything in the physical world.
-As a Pre-Socratic philosopher, Leucippus was among the first thinkers to look to science and reason instead of mythology in order to explain the universe.
-In doing so, Leucippus developed the theory of atomism. -
460 BCE
Democritus
-the first person to suggest that materials were made up of smaller things. He called these things 'atomos'.
- theorized that every single material had its own 'type' of atomos and that no matter how small you cut something up, it would always have the same properties.
-He said that matter cannot be created or destroyed. -
384 BCE
Aristotle
-Aristotle was a philosopher, not a scientist.
-He did not believe in the atomic theory and he taught so otherwise. --He thought that all materials on Earth were not made of atoms, but of the four elements: Earth, Fire, Water, and Air.
-He believed all substances were made of small amounts of these four elements of matter. -
1493
Paracelsus
-16th-century Swiss natural philosopher
-put together in an almost impenetrable combination the Aristotelian theory of matter, alchemist correspondences, mystical forms of knowledge, and chemical therapy in medicine -
1494
Georgius Agricola
-German mineralogist and metallurgist.
-known as "the father of mineralogy." -
Robert Boyle
-It is Boyle's Law for which he remains most famous.
-It states that if the volume of a gas is decreased, the pressure increases proportionally.
-Understanding that his results could be explained if all gases were made of tiny particles, Boyle tried to construct a universal 'corpuscular theory' of chemistry.
-He defined the modern idea of an 'element', as well as introducing the litmus test to tell acids from bases, and introduced many other standard chemical tests. -
Antoine Lavoisier
-Known for his experimental skills.
-One of his favorite experiments was turning HgO to Hg+O.
-This experiment helped him come up with the Law of Conservation
-This law states that matter cannot be created or destroyed.
-Matter rearranged, but never disappeared.
-He began the conversation of what an atom was exactly. -
Joseph Proust
-Proust stated the Law of Definite Proportions.
-The law states that the ratio of elements in a compound is always the same/constant.
-He also hinted at the 'lego'ness of matter; he believed that matter could be put together in certain patterns to make bigger, different, unique matter
-He set it up for Dalton to create the Law of Multiple Proportions and ultimately his Atomic Theory. -
John Dalton
The main points of Dalton's atomic theory are:
-Elements are made of extremely small particles called atoms.
-Atoms of a given element are identical in size, mass and other properties.
-Atoms of different elements differ in size, mass and other properties. -Atoms cannot be subdivided, created or destroyed. -
Amadeo Avogrado
-Italian scientist.
-Most noted for his contribution to molecular theory now known as Avogadro's law
-States that equal volumes of gases under the same conditions of temperature and pressure will contain equal numbers of molecules.
-The law was only accepted after his death. -
Joseph Gay-Lussac
-French chemist that proposed two fundamental laws of gases in the early 19th century.
-While one is generally attributed to a fellow countryman, the other is well known as Gay-Lussac’s law.
-Pioneered investigations into the behavior of gases, established new techniques for analysis, and made notable advances in applied chemistry.
-his "Law of Combining Volumes of Gases" determined that when different gases reacted, they would always do so in small whole number ratios -
Jons Jakob Berzelius
-Swedish chemist.
-One of the first European scientists to accept John Dalton's atomic theory and to recognize the need for a new system of chemical symbols.
-He was a dominant figure in chemical science.
- Conducted pioneering experiments in electrochemistry and established the law of constant proportions, which states that the elements in inorganic substances are bound together in definite proportions by weight. -
J.J. Thomson
-English physicist and Nobel Laureate in Physics.
-Credited with the discovery and identification of the electron; and with the discovery of the first subatomic particle.
-Discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged.
