Film: 6370

Science | 1950 | Sound | B/W

Synopsis:

The Atomic Theory

A long shot of the Royal Society, London, the words London and 1826 AD appear superimposed on the Royal Society buildings. The front page of a Royal Society book "Six Discourses" presented by Sir Humphry Davy who presented John Dalton and James Ivory with a prize. Close up of a page written by John Dalton and by James Ivory, they developed "The Chemical Theory of Definite Porportions" also known as the atomic theory. An historical reconstruction of the eighteen century presentation of a medal by Sir Humphry Davy to Dalton. Another historical reconstruction describing Dalton working in his chemistry laboratory, the bench is covered with instruments while the walls have shelves with glass bottles. Close up of Dalton weighing a chemical compound, he is working out the relative combining weights of elements. Close up of the front page of Dalton's book "A New System of Chemical Phylosophy" published in 1808, followed by more close ups of several pages and focusing on a page showing atomic structures and another page showing some of the chemical elelements (atom) weights. A short animation explains Dalton's atomic theory: matter is composed of small particles (cannot be split up any further), circles represent atoms and all atoms of one element are exactly alike, atoms are industructive and cannot be created, chemical combination occurs between small whole numbers of atoms (these combinations of atoms are called molecules). A close up of a list of symbols invented by Dalton to represent the atoms of different elements. A view of some molecules represented by Dalton. 19 century chemists at work in their laboratories. A short animation explains the 19 century connection that was sort between atomic weight and chemical properties ( this eventually lead to Mendeleef's periodic table in 1869), the elements in the periodic table are arranged from left to right in assending order of atomic weight, Mendeleef left places in the periodic table for elements not yet discovered, he in fact predicted the missing elements atomic weight. An historical reconstruction of Michael Farraday, Michael Faraday, working on the decomposion of solutions by an electric current, he proved that a definite quantity of electricity was associated with definite ammounts of elements produced at the electrode, that is, with definite number of atoms. Close up of Farraday nodding his head over his chemical apparatus. A short animation that explains Farraday's idea that electricity is atomic in nature and that there are two kinds of electricity called like and unlike charges, unlike charges attracted each other and like charges repelled each other, these charges became known as positive and negetive charges. Another short animation showing a sodium chlorine solution being electrified which results in the production of positive sodium ions and negative chlorine ions, sodium ions go to the cathod while chlorine ions go to the anode. A 19 century chemist working on liquid or gas to show that molecules are in a state of perpertual motion. The botanist Robert Brown is looking under the microscope, he observed Brownian motion. Close up of particles in suspension. A short animation shows that 27 million billion molecules are contained in one cm cube of gas at zero degrees centigrade at normal pressure. A soap bubble is overlaid over a small box held by two fingers. An animation describes the thickness of the soap bubble in molecular terms. Lord Rutherford talking about the 19 century atom.


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