International projectionist (Jan 1943-Dec 1944)

VOLUME XIX JULY 1944 NUMBER 7 Projectionists' Course on Basic Radio and Television By M. BERINSKY, E. E. MEMBER OF INSTITUTE OF RADIO ENGINEERS L—THE NATURE OF ELECTRICITY This is the first of a series of articles on basic radio, television and electricity written especially for the readers of I. P. The author, a graduate of the Massachusetts Institute of Technology and member of the Institute of Radio Engineers, has been conducting courses on these subjects for the past two years for the members of one of the largest local unions in the Alliance. The articles are written in the language of the layman and are devoid of complicated mathematics. We suggest that the readers carefully study them and, without a second reference to the written material, answer the questions appended to each article. The correct answers will appear in the following issues. As an added service to our readers, the author will be glad to answer all questions on electricity, radio, sound, and television. Questions pertaining to specific equipment should contain the name and model number. Address all communications to this magazine. RADIO, sound equipment, and television have one thing in common — they all depend upon electricity for their operation and motivation. To achieve proficiency in these subjects a knowledge of the fundamentals is essential. First, what is electricity? This question seems to be a very simple one to answer, and yet a complete answer never has been given. A famous scientist stated recently that 96% of our knowledge as to the true nature of electricity has not been expounded to date. The phenomenon that is electricity has been known to civilized peoples for many centuries. The ancient Greeks discovered that when an amber rod was vigorously rubbed on a piece of cloth it acquired the property of attracting to it small pieces of paper, cloth, dust, and other non-metallic substances. It is from the Greek word "electron" meaning amber, that the word "electricity" was derived. Although our knowledge of electricity is limited to some extent, we have been able to find out a great deal about its nature, its effects, and its applications. We know, for example, that all forms of matter contain some electrical charges. But what is matter? Everything that goes into the make-up of our universe may be classified as matter. The air that we breathe, the water that we drink, the ground that we walk upon, all are considered to be what we call matter. Matter exists in three fundamental forms, or "states," as they are called by scientists. The three states of matter are (1) the solid state, (2) the liquid state and (3) the gaseous state. The application of varying degrees of heat to matter will result in a change of state taking place. Let us first consider a piece of ice (matter in the solid state). When the ice is in physical contact with any body that is warmer than 32 degrees F., it will slowly begin to melt until it turns into water. A change of state has taken place and the solid piece of ice has now turned into a liquid. Any further application of heat will have little effect upon the state of the liquid, until enough heat is added to cause the water to become vaporized. When the water has begun to vaporize, it will turn into steam, and we know that steam is a gas. The reason why these changes take place in various kinds of matter is because changes take place in the tiniest particles from which matter is composed. The number and arrangement of these extremely small particles is responsible for the existence of many different kinds of matter, all reacting in their own way to the influence of electricity. Atoms, Molecules and Electrons All matter is made up of 92 fundamental constituents called elements. Matter made up of only one element is said to exist in the free state. Examples of free elements are iron, copper, carbon, tungsten, aluminum, radium, gold, and silver. These free elements may be broken down into very minute particles, so small that billions of them could be JULY 1944