81. In and around Amsterdam (10:09)

Date:
1949
Summary:
Surveys the city of Amsterdam and the surrounding countryside. Shows typical sights and important buildings, residential areas, contrasting village scenes, and the shipping industry. | Surveys the city of Amsterdam and the surrounding countryside. Shows typical sights and important buildings, residential areas, contrasting village scenes, and the shipping industry.

82. In this crisis : Trenton, 1776 (21:16)

Date:
1953
Summary:
Teaching Film Custodians abridged classroom version of an episode of the DuPont sponsored Cavalcade of America television series, "In This Crisis" (season 1, episode 7), which aired December 24, 1953 on NBC-TV. This historical drama features John Honeyman, butcher and American patriot, who, pretending to be a Tory, spies on the Hessions to gain military intelligence, which informs Washington's decision to cross the Delaware and attack the Hessions in the December, 1776 battle at Trenton.

83. Inbreeding and heterosis (29:48)

Date:
1959
Summary:
Discusses the effect of various levels of inbreeding (self-fertilization, sib matings, half-sib matings, cousin marriages) upon making heterozygous genes homozygous with the consequent loss of vigor. Presents data for the increased risk of genetic defect from cousin marriage in studies of phenylketonuria, of a Japanese population and a French population. The concept and estimation of lethal equivalents are given. Shows how increases in heterozygosity increase vigor (heterosis); hybrid vigor in corn in described in detail. Lecture given by Dr. J. F. Crow.

84. Installing surface metal raceway (21:15)

Date:
1945
Summary:
Shows how to plan the job; how to use molding raceway fittings; how to install a molding raceway run to a ceiling outlet; how to install a run from a ceiling outlet to a wall switch; how to install a run from a ceiling outlet to a wall fan; and how to install a run to a floor outlet.

85. Interpreting test scores realistically (17:15)

Date:
1961
Summary:
Demonstrates use of standard error, comparison of scores with test norms in interpretation of test scores, and use of percentile bands rather than points. | Presents a lecture by Dr. Scarvia B. Anderson, who demonstrates two important principles of test interpretation--(1) any test score is only an estimate of a student's ability, and (2) percentages are meaningful only if the characteristics of the group on which norms are based are known. Golf pro Ernie Pognotta helps to show similarities in basic principles of measurement in golf and in test scores. Dr. Anderson emphasizes that meaning comes from comparison in interpreting test scores.

86. Introduction to Music Reading (11:52)

Date:
1962
Summary:
Uses animation to compare written music symbols with written words and emphasizes that music is a written language with its own symbols. Introduces the five-line staff and the G clef as the basic structures upon which music is written. Shows how to develop pitch memory, introduces a basic rhythmic and tonal vocabulary, and combines these vocabularies into songs.

87. Ionization and ionic equilibrium (16:09)

Date:
1960
Summary:
Uses animation and laboratory demonstrations to explain the formation of ions in ionization and the effects ions produce. Presents hydrochloric acid as a typical electrolyte that ionizes in water permitting the solution to conduct an electric current. The polarity of the water molecule is illustrated and valance, electrovalance, and the effect of ionization on the boiling and freezing points of solutions are explained.

88. It's wonderful being a girl (20:06)

Date:
1966
Summary:
This older film is directed to young girls. Using diagrams, it helps them learn about menstruation and gives them a healthy understanding of the physical and emotional changes that occur in growing up.

89. Jack Visits Costa Rica (10:28)

Date:
1947
Summary:
Tells the story of a boy's trip to visit friends in Costa Rica. He lives in the home of an upper-class Costa Rican family, sharing their life and activities. He goes to see the public schools, the city market, native animals in the zoo, and the large plantations. Emphasizes the similarities and differences between life in Costa Rica and the United States.

90. Joining and gluing (14:30)

Date:
1956
Summary:
Explains the principles and demonstrates procedures and materials for joining and gluing wood, emphasizing the mortise-and-tenon and edge-to-edge joints. Shows procedures for application of glue and the use of clamping tools in gluing.