Educational screen & audio-visual guide (c1956-1971])

FILM EVALUATIONS by L. C. Larson and Carolyn Guss Nuclear Radiation Detectors (Cenco Educational Films, 1700 West Irvinp, Park Road, Chicago 13, Illinois) 17 minutes, 16mni sound, color rind black and white, no date. $150 and $75. Description Nuclear Radiation Detectors uses live-action photography and animation to survey alpha, beta and gamma radiation and their characteristics; the instruments used to measure these t\pes of radiation; and the principles )<isic to the operation of these instruments. Detection instruments discussed include the gold lead electroscope, lieiger counter, cloud and bubble •hambers, and scintillation counters. The film begins by developing the malogy between the use of our senses f sight and feeling for the detection f light and heat radiation, and the leed for special techniques to detect adio and x-ray radiation. Animation i employed to distinguish between lectromagnetic and corpuscular radia ion in relationship to nuclear re ctions. Alpha and beta particles are iven as examples of corpuscular idiation respectively consisting of ositively charged helium nuclei and igh speed electrons. Gamma rays ■present electrically neutral electro lagnetic radiation. The gold leaf electroscope utilizes le ionization caused by nuclear idiation to detect the presence of idiation. Animation and live-action holograph) are employed to show le construction of the instrument and s charging and discharging due to nclear radiation. Animation is again sed to explain ionization caused by l^ha and beta particles and how this iffers from the ionization resulting im gamma radiation. The operational principles of ioni ition chambers and Geiger tubes are ■scribed through animation. It is )inted out that a Geiger tube's high nf between its electrodes increases ^ sensitivity and range of usefulness. number of current pulses can be isured by a variety of devices; iig those shown are meters and II TS. iiploying animation, the penetraMi ability of alpha, beta and gamma radiation is compared as an introduction to the need for the open-air detector to measure the presence of alpha particles and weak beta radiation; since even a thin sheet of paper can stop an alpha particle. To make records of the ionized tracks of various nuclear particles, cloud and bubble chambers and thick photographic emulsions are useful. Live photography is used to depict the structure and operation of the Wilson and continuous cloud chambers and several actual tracks are observed in The Cim WAR A Brilliant New Historical Film Series Produced by: The Westinghouse Broadcasting Company Distributed by: Association Films, Inc. An outstanding, award-winning television series traces the history of the four-year conflict, the events leading to the war, and post-war reconstruction. Available now for schools, colleges and community groups, THE AMERICAN CIVIL WAR comprises thirteen half -hour I6mm sound motion pictures, utilizes more than 3,000 Mathew Brady photographs, and is supported by an original musical score. Chronicled in intimate and revealing detail, the battles, the strategies, and the troubled times surrounding the war are covered in this pictorial history. Each episode may be used individually or in series, and may be obtained at a rental price of $7.50 per subject, or may be leased for the life of the print at $150.00 per subject or $1875.00 for the series of 13 films. Rental fees will be discounted from lease price if prints are leased within six months. STORM OVER SUMTER . MR. LINCOLN'S POLITICS • BRADY OF BROADWAY . IRONCLAD SEARCH FOR THE MONITOR . ANTIETAM • HOMEFRONT . BATTLE OF GETTYSBURG • THE MISSISSIPPI RIVER CAMPAIGN • BLOCKADERS • GRANT AND LEE . APPOMATTOX . NIGHT OF THE ASSASSINS For additional information please ivrite to Dept. CW ASSOCIATION FILMS, Inc. 347 Madison Avenue, New York 17, N. Y. jin'CATioNAL Screen a.\d Audiovisual Guide — September, 1961 493