Correspondence of Benjamin Franklin provides authenticity to a historical account of early work in the field of lightning. Present-day theories concerning the formation and propagation of lightning are expressed and photographic evidence provided. (CP)

Photographs of snow covered buildings are used to illustrate thermal radiation from various types of structures and the effect of insulation on heat loss. (CP)

Describes petroleum exploration techniques, particularly the interpretation of seismograms. (CP)

Considers teaching to be the synthesis of a body of knowledge and the art of presentation. Comments on the American science teacher education process, particularly at the graduate level. (CP)

Details construction of an inexpensive electronic auditory device in which the resistance in parallel with the device is inversely proportional to the frequency of sound produced. (CP)

Describes and compares three analytical methods of interpreting constant acceleration data from a stroboscopic picture or spark record. (CP)

Photographs show three simple demonstrations of deceptive centers of gravity. (CP)

Provides a refinement to the Harvard Project Physics Course handbook exercise "Stepwise Approximation to an Orbit." (CP)

Provides a technique for the determination of the mass of a large, movable object. (CP)

The circular motion observed when water drains into a smooth opening is analyzed. This action, as well as cycloidal atmospheric motion, is explained as the result of rotation of the coordinate system. (CP)

Explains the operation of the Magnetohydrodynamic (MHD) generator and advantages of the system over coal, oil or nuclear powered generators. Details the development of MHD generators in the United States and Soviet Union. (CP)

Describes construction of a variety of relatively inexpensive cameras for astronomical purposes. (CP)