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He found that there are only five solid shapes whose sides are made from regular polygons -
Alchemists invented experimental techniques and laboratory tools still used by chemists today. They were also the first to isolate certain metals we now know to be elements, including antimony, arsenic and zinc. -
taught that there were substances called atoms and that these atoms made up all material things. The atoms were unchangeable, indestructible, and always existed. -
He made pioneering contributions to all fields of philosophy and science, he invented the field of formal logic, and he identified the various scientific disciplines and explored their relationships to each other. Aristotle was also a teacher and founded his own school in Athens, known as the Lyceum. -
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Discovered that the volume of a gas decreases with increasing pressure -
He established the law of conservation of mass, determined that combustion and respiration are caused by chemical reactions with what he named “oxygen,” -
Made in the 1800's by John Dalton
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known for introducing the atomic theory into chemistry. -
Created the Periodic Table -
Discovered Electrons -
Marie Curie is remembered for her discovery of radium and polonium, and her huge contribution to finding treatments for cancer. -
Planck postulated that the energy of light is proportional to the frequency, and the constant that relates them is known as Planck's constant. His work led to Albert Einstein determining that light exists in discrete quanta of energy, or photons. -
Made by J.J. Thompson -
In 1910 Robert Millikan succeeded in precisely determining the magnitude of the electron's charge. -
Niels Bohr proposed a model of the atom in which the electron was able to occupy only certain orbits around the nucleus. This atomic model was the first to use quantum theory, in that the electrons were limited to specific orbits around the nucleus. -
In 1913, while working at the University of Manchester, he observed and measured the X-ray spectra of various chemical elements using diffraction in crystals. Through this, he discovered a systematic relation between wave- length and atomic number. This discovery is now known as Moseley's Law. -
Ernest Rutherford is known for his pioneering studies of radioactivity and the atom. He discovered that there are two types of radiation, alpha and beta particles, coming from uranium. He found that the atom consists mostly of empty space, with its mass concentrated in a central positively charged nucleus. -
developed the special and general theories of relativity. -
Werner Heisenberg discovered the uncertainty principle, which states that the position and the momentum of an object cannot both be known exactly. -
Assuming that matter could be regarded as both particles and waves, in 1926 Erwin Schrödinger formulated a wave equation that accurately calculated the energy levels of electrons in atoms. -
The electron cloud model was developed in 1926 by Erwin Schrödinger and Werner Heisenberg. -
Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons -
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. Discovered by Heinrich R. Hertz
