Age of Reason

168O's English scientist Isaac Newton formulated three laws of motion and a law of universal gravitation and showed how these laws govern objects on Earth and in space. He also studied lenses and published a particie theory of light.

1690 Dutch physicist Chrisliaan Huygens published a wave theory of light.

early 1700's Georg Ernst Stahl, a German chemist and physician, developed the phlogiston theory to explain burning.

1735 Swedish naturalist Carolus Linnaeus published a system for naming and classifying plants according to their structures. He later applied this system to animals.

1749 French naturalist Comte de Bufon began publishing his Natural History, a multivolume text that included theories on the evolution of plants and animals and the formation of the Earth.

1750's Scottish chemist and physician Joseph Black identified carbon dioxide, the first gas recognized as different from air.

1750's American statesman and scientist Benjamin Franklin made important discoveries about the properties of electricity and proved that lightning is electricity.

1755 Immanuel Kant, a German philosopher, proposed the theory that the planets and the sun were fonned from a nebula.

Benjamin Franklin A noted scientist was a major figure in the Enlightenment and the history of physics for his discoveries and theories regarding electricity.

James Hutton was a Scottish geologist, physician, chemist, naturalist, and experimental farmer. He is considered the father of modern geology.

1766 Henry Cavendish, an English scientist, identified hydrogen as an element.

1770's Swedish chemist Cad Scheele and English chemist Joseph Priestley discovered oxygen independently.

1781 British astronomer William Herschel discovered Uranus.

1785 Scottish physician James Hutton presented the theory—later called uniformitarianism—that the Earth is gradually changing and will continue to change in the same ways.

1789 French chemist Antoine Lavoisier published the first modern chemistry textbook. He explained burning and proved that matter cannot be created or destroyed - only chemically changed.

1798 Americanborn scientist Benjamin Thompson stated that the motion of particles in a substance produces heat.

Modern times

1800 Italian scientist Alessandro Volta invented the first electric battery.

early 1800's French naturalist Baron Cuvier made major contributions in comparative anatomy and helped launch palaeontology.

1800's The first weather maps were drawn, and scientists made advances in the study of weather through lhe use of new instruments that measured humidity, wind, air pressure, and precipitation.

1803 English chemist John Dalton proposed an atomic theory that staled that each chemical element has its own kind of atoms.

1811 Amedeo Avogadro, an Italian physicist, proposed that equal volumes of all gases at the same temperature and pressure contain equal numbers of particles.

1815 William Smith, an English civil engineer, published the first geological maps. He was the first to use fossils to determine the age of rocks.

1820 Danish physicist Hans Christian Oersted and French physicist Andre Marie Ampere established the relation between electricity and magnetism.

1828 German chemist Fricdrich Wohler became the first person lo create an organic substance (synthetic urea) from inorganic chemicals.

John Dalton, an English chemist, meteorologist and physicist. He is best known for his pioneering work in the development of modern atomic theory.

Michael Faraday, an English chemist and physicist (or natural philosopher, in the terminology of the time) who contributed to the fields of electromagnetism and electrochemistry.

1830 Scottish geologist Charles Lyell pub lished the first volume of The Principles of Geology, which explained clearly and carefully how the Earth had evolved over a long period of time.

1831 Physicists Michael Faraday of England and Joseph Henry of the United States dis covered independently that a moving mag net can induce an electric current in a wire.

1838-1839 German scientists Matthias Schleiden and Theodor Schwann proposed that all living things are made up of cells.

1830's-1840's Louis Agassiz, a Swissborn naturalist, showed that glaciers once covered large areas of the Earth.

1846 German astronomer Johann Galle and his assistant Heinrich d'Arrest discovered Neptune.

1846 American physician Crawford Long and American dentist William T. G. Morton discovered ether, the first safe anaesthetic.

1847 English physicist James Joule showed that mechanical energy can be converted to heat energy according to a mathematical formula.

late 1840's Scientists including Lord Kelvin of the United Kingdom and Hermann von Helmholtz of Germany proposed that energy cannot be created or destroyed.

mid1800's Gregor Mendel, an Austrian monk, discovered the basic statistical laws of heredity.

mid to late 1800's French chemist Louis Pasteur made contributions to chemistry, medicine, and industry. He discovered that some diseases are caused by bacteria and that heat can preserve food.

1850's German chemist Robert Bunsen and physicist Gustav Kirchhoff designed the first spectroscope and discovered that atoms of each element produce a unique set of spectral lines.

1856 William Perkin, an English chemist, made the firs! synthetic dye.

1858 Rudolf Virchow. a German doctor and scientist published Cellular Pathology, which described important new findings in the study of diseased body tissue.

French physicist Marie Curie was codiscoverer, with Pierre Curie, of radium.

Charles Robert Darwin, was an English naturalist who realised and presented compelling evidence that all species of life have evolved over time from common ancestors, through the process he called natural selection.

1859 English naturalist Charles Darwin published his theories of evolution in The Origin of Species. This book explained how plants and animals have changed their characteristics through natural selection over the ages.

1859 Scottish physicist James Clerk Maxwell announced his kinetic theory ol: gases, which explains the properties of gases in relation to the behaviour of Iheir molecules. He later proposed that visible light consists of electromagnetic waves.

1869 Russian chemist Dmitri Mendeleev published his periodic table of chemical elements.

1870's American physicist Josiah Willard Gibbs developed the phase rule, which explains the physical relationship between the solid, liquid and gaseous states of a substance.

1876 German doctor Robert Koch announced his discovery that specific bacteria cause certain diseases.

1887 German physicist Heinrich Hertz discovered the photoelectric effect and proved James Clerk Maxwell's theory of electromagnetism and light.

1887 American physicists Albert Michelson and Edward Morley conducted an experiment that eventually disproved the existence of the ether, then believed to be a substance that filled all space.

1895 German physicist Wilhelm Roentgen discovered X rays.

1896 Antoine Henri Becquerel discovered natural radioactivity.

1897 English physicist Joseph J. Thompson discovered the first subatomic particle, later called the electron.

1898 French physicists Marie and Pierre Curie discovered radium, which led to a better understanding of radioactivity.

1900 German physicist Max Planck proposed his quantum theory, which explains that energy is released in separate units, called quanta.

early 1900's Norwegian meteorologist Vilhelm Bjerknes discovered that the movement of huge masses of air, called fronts, caused changes in weather.

1902 British physiologists Ernest Henry Starling and William Maddock Bayliss discovered chemical messengers in the human body, which Starling later named hormones.

1905 German physicist Albert Einstein published his special theory of relativity, which revised many concepts of Newton's physics and proposed a new way of thinking about space and time.

Albert Einstein's theories changed scientific understanding of time and space.

Ernest Rutherford, was a New Zealand born British chemist and physicist who became known as the father of nuclear physics.

1907 German bacteriologist Paul Ehrlich founded the field of chemotherapy, in which diseases are treated with chemicals.

1910 American biologist Thomas Hunt Morgan and his associates proved thai genes are the units of heredity and that they are arranged in an exact order on cell structures called chromosomes.

1911 British physicist Ernest Rutherford the orized that the mass of an atom is concentrated in a nucleus, which is surrounded by electrons travelling ai incredible speeds.

1912 German meteorologist Alfred Wegener published his theory of continental drift, which proposed that the continents move around on the surface of the Earth.

1913 Danish physicist Niels Bohr proposed a description of atomic structure, suggesting thai electrons travel in specific orbits.

1915 Einstein published his general theory of relativity, which expanded his earlier theory.

1916 American chemist Gilbert Lewis stated that chemical bonds are formed when atoms share electrons. He also explained the va lency of chemical elements.

1924 French physicist Louis de Broglie introduced the wave theory of the electron.

1926 American geneticist Thomas Morgan Hunt published 77ft' Theory of the Gene, demonstrating that certain characteristics are carried from generation to generation through genes.

1927 German physicist Werner Heisenberg formulated the uncertainly principle, which states that both the position and momentum of a subatomic particle cannot be accurately determined simultaneously. His work in atomic theory led to the development of quantum mechanics.

1928 Scottish bacteriologist Alexander Fleming discovered penicillin, the first antibiotic.

1929 American astronomer Edwin Hubble demonstrated that the universe is expanding.

1929 British physicist John Cockcroft and Irish physicist Ernest Walton built the first particle accelerator to breakdown atomic nuclei.

Sir Alexander Fleming, a Scottish biologist and pharmacologist. His best-known achievements are the discovery of the enzyme lysozyme in 1923 and the antibiotic substance penicillin.

Thomas Hunt Morgan, an American geneticist and embryologist.His research moved to the study of mutation in the fruit fly Drosophila melanogaster.

1930 British physicist Paul Maurice Dirac suggested that protons and elections could be composed of either positive or negative energy, thus predicting the existence of antimatter.

1930 American astronomer Clyde Tombaugh discovered Pluto.

1931 German scientists demonstrated the first electron microscope.

1931 Karl Jansky, an American engineer, identified radio waves coming from beyond the solar system.

1933 American scientist Thomas Morgan described the role of the chromosomes in heredity.

1935 Japanese physicist Hideki Yukawa predicted the existence of particles other than protons and neutrons in the nucleus, which he called mesons.

1938 German physicisis Otto Hahn and Fritz Strassmann achieved fission of the uranium atom.

1942 Italianborn physicist Enrico Fermi and his coworkers at the University of Chicago achieved the first controlled nuclear chain reaction.

1953 American biochemist James Watson and British physicist Francis Crick created a model of the molecular structure of deoxyribonucleic acid (DNA), which carries genetic information.

1963 Astronomers discovered quasars.

1964 American physicists Murray GeilMann and George Zweig proposed the existence of subunits of protons and neutrons, called quarks.

1965 Radio astronomers discovered background microwave radiation that may have been produced as a result of the big bang, a possible origin of the universe.

1968 A group of American scientists proposed the theory of plate tectonics to explain the movement of continents on the Earth's surface.

James Watson was codiscoverer, with Francis Crick, of the molecular structure of DNA.

Thomas Robert Cech, is a Nobel Laureate in chemistry. His main research area is that of the process of transcription in the nucleus of cells.

1974 American physicists Burton Richter and Samuel Ting discovered a type of subatomic panicle called the psi particle or J particle. Their discovery supported the theory of quarks.

1979 Scientists discovered deepsea bacteria capable of living without oxygen.

1979 Researchers in what was then West Germany discovered the gluon, an elementary particle which carries the strong force that binds the atomic nucleus.

1983 Researchers led by Carlo Rubbia of Italy discovered two types of subatomic particles, the W particle and the Z particle. These may be sources of the weak force, which controls disintegration of atoms.

1989 American scientists Thomas Cech and Sidney Altman independently discovered that certain RNA molecules can aid chemical reactions in cells.

1989 American scientists Steven Rosenberg, R. Michael Blaese. and W. French Anderson carried out the first gene transfer into humans.

1994 American astronomer Alexander Wolszczan discovers the first known planets outside the solar system orbiting a pulsar 1,500 lightyears away.