Physics: “Mechanical Energy and Thermal Energy” 1959 PSSC; MIT; Jerrold Zacharias

Published on December 29, 2017

Physical Science Study Committee Films (PSSC) playlist:

Physics & Physical Sciences playlist:

“Shows several models to illustrate both the bulk motion and random motion of molecules. Shows their interconnection as the energy of bulk motion. Discusses thermal conduction and absolute temperature scale.”

Public domain film, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

Wikipedia license:

In the physical sciences, mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object. The principle of conservation of mechanical energy states that in an isolated system that is only subject to conservative forces the mechanical energy is constant. If an object is moved in the opposite direction of a conservative net force, the potential energy will increase and if the speed (not the velocity) of the object is changed, the kinetic energy of the object is changed as well. In all real systems, however, nonconservative forces, like frictional forces, will be present, but often they are of negligible values and the mechanical energy’s being constant can therefore be a useful approximation. In elastic collisions, the mechanical energy is conserved but in inelastic collisions, some mechanical energy is converted into heat. The equivalence between lost mechanical energy (dissipation) and an increase in temperature was discovered by James Prescott Joule.

Many devices are used to convert mechanical energy to or from other forms of energy, e.g. an electric motor converts electrical energy to mechanical energy, an electric generator converts mechanical energy into electrical energy and a steam engine converts heat energy to mechanical energy…

In thermodynamics, thermal energy refers to the internal energy present in a system due to its temperature. The concept is not well-defined or broadly accepted in physics or thermodynamics, because the internal energy can be changed without changing the temperature, and there is no way to distinguish which part of a system’s internal energy is “thermal”. Thermal energy is sometimes used loosely as a synonym for more rigorous thermodynamic quantities such as the (entire) internal energy of a system; or for heat or sensible heat which are defined as types of transfer of energy (just as work is another type of transfer of energy). Heat and work depend on the way in which an energy transfer occurred, whereas internal energy is a property of the state of a system and can thus be understood even without knowing how the energy got there…

Jerrold Reinach Zacharias (January 23, 1905 – July 16, 1986) was an American physicist and Institute Professor at the Massachusetts Institute of Technology, as well as an education reformer. His scientific work was in the area of nuclear physics…

Zacharias was involved in both the Radiation Laboratory at MIT and the Manhattan Project. He helped build the MIT physics department after the war, and was responsible for recruiting Bruno Rossi and Victor Weisskopf to the Institute. During the Cold War he was the head of a number of defense-related studies hosted at MIT (Project Hartwell, Project Charles, Project Lamp Light) and later he both founded and ran the Physical Science Study Committee, which was influential in changing physics education in the United States in the wake of Sputnik (1957)…

The Physical Science Study Committee, usually abbreviated as PSSC, was inaugurated at a 1956 conference at MIT to review introductory physics education and to design, implement, and monitor improvements. It produced major new physics textbooks, instructional movies, and classroom laboratory materials, which were used by high schools around the world during the 1960s and 1970s and beyond…

By the 1964–1965 school year, about half the US students enrolled in high school physics (200,000 students, 5000 teachers) were reportedly using the PSSC course materials…

Enjoyed this video?
"No Thanks. Please Close This Box!"