![]() ![]() ![]() This he published as ‘Periodic Table of Elements’ and predicted that the missing elements in the table are the elements yet to be discovered Discovery of Electron When elements combine, they do so in defined whole number ratiosġ869 Dmitri Ivanovich Mendeleev, while working for his book, arranged the elements as per their atomic weights and found a striking pattern.Chemical reaction involve combination of atoms.All atoms of an element are identical atom of different elements have different properties.All matter is composed of indivisible particles called ‘Atom’.In 1803, Dalton developed the First Atomic Theory with four main concepts: They also found that some substances could combine to form a new substance. In the 17 th and 18 th century, scientist, particularly chemists started examining nature of these elements and found that they are constituted of even smaller elements like water is formed from Oxygen & Hydrogen and air has many small particles and components. However, Aristotle’s view prevailed Early Atomic Theory This ‘uncutable’ part, he called ‘Atomos’ which in modern times became ‘Atom’. In 400 BC another Greek philosopher, Democritus believed that if we cut a stone, we will reach a point where it can not be cut further. Greeks, particularly Aristotle postulated that all things are made by combination of Earth, Water, Air and Fire. Dharti, Jal, Vayu, Akash & Agni (Earth, Water, Air, Sky and Fire). Man has always wondered ‘what makes all things around us’.The following shloka from Gita describes Indian belief of ‘Panch Mahabhut’, i.e. He died in California in 1953 Atom & Electron – Old Beliefs He also measured the value of ‘Planck’s Constant’ by measuring photoelectric emission of various metals He was first President of California Institute of Technology and worked on ‘Cosmic Rays’. ![]() He was awarded Noble Prize in 1923 for this experiment.Īfter Einstein announced his analysis of Photo Electric effect in 1905, Millikan took up detailed study which confirmed Einstein’s ‘Photon Theory of Light’. In 1909, he worked on ‘Oil drop experiment’ and measured charge of electron. He was Doctor of Physics from Columbia University and became a Professor of Physics at Chicago University. Robert Andrews Millikan was born in Illinois, USA in March 1868. The experiment used a simple table-top device and is exemplified by its simplicity and beauty of conceptualization and analysis His Life Oil-drop experiment was the first direct measurement of the electric charge of a single electron and thus confirmed the existence of electron which was discovered by J J Thomson in 1897. This has been rated at number 3 of the Ten Best experiments. ![]() Robert A Millikan American Physicist (1868 – 1953) carried out the Oil Drop Experiment in 1909 to measure the charge of a single electron. Oil Drop Experiment – Robert Millikan – 1909 Summary Samsung galaxy y cas… on Best experiments – Inter…īest experiments… on Best Experiments – Inter… Best Experiments – Electron Diffraction – Black Body Radiation.Best experiments – Electron Diffraction – Photo electric effect.Best Experiment – Electron Diffraction – Bohr Atom.Best experiments- Electron diffraction – Broglie’s theory.Best experiments – Electron Diffraction – Davisson Germer Expr. 1927. ![]()
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