Presents a laboratory exercise designed to introduce graphical extrapolation. Major advantages of the method are in its simplicity and speed. The only measuring devices are a centimeter ruler and a micrometer caliper to check wall thickness. (JN)

Describes a radiation counter comparable to commercial units which costs less than $100. It consists of six sections: Geiger-Mueller tube and holder; high voltage supply; low voltage supply; pulse shaping circuit; "start/stop counts" gating circuit; and counter/display. List of materials needed and schematic diagrams are included. (JN)

Describes (1) a tri-color light-emitting diode (LED) and (2) modification of a demonstration using a dollar bill held between two soft drink bottles, one inverted upon another mouth-to-mouth. The modification consists of filling the bottles with water to increase their mass. (JN)

Describes activities designed to discover what the fluid is in bubble lights used on Christmas trees. Also describes activities using soda straws (to make music and to make smoke). (JN)

Why does a football thrown with a spin keep its axis pointing along its trajectory? (It's most obvious in a long, soft pass. Even with a wobbly pass the ball's axis wobbles around the line of its trajectory). The answer to this question is provided. (JN)

Discusses how LOGO programing language is used in physics teaching at Piedmont Virginia Community College in West Virginia. Also: (1) considers the characteristics of the language which make it attractive in physics teaching; (2) lists sample programs; (3) offers instructional strategies; and (4) presents student reactions. (JN)

Discusses topics related to high-energy, gamma-ray astronomy (including cosmic radiation, gamma-ray detectors, high-energy gamma-ray sources, and others). Also considers motivation for the development of this field, the principal results to date, and future prospects. (JN)

Describes 10 computer programs used to draw diagrams usually drawn on chalkboards, such as addition of three vectors, vector components, range of a projectile, lissajous figures, beats, isotherms, Snell's law, waves passing through a lens, magnetic field due to Helmholtz coils, and three curves. Several programming tips are included. (JN)

A relatively simple opto-electronic setup is described that utilizes a cadmium sulphide (CdS) photoconductive cell to detect resonance of a stretched vibrating string or wire. The display may be either an oscilloscope or a frequency counter. Also describes an inexpensive socket for flanged-base light bulbs. (JN)

Examines techniques used to make ultrasensitive spectroscopic measurements. They include excitation, thermal lens, photo acoustic, and ionization spectroscopies. Guidelines and methods are provided for each technique; common uses and applications are explained. (DH)

Lists postulates on which the author bases his approach to large class instruction. Suggestions are given for such administrative, operational, and academic procedures as organizing handouts and class information; avoiding "busy work"; finding out about the students (personal and academic); making an assignment due every class; and providing quick…

Discusses motions of the sun and earth in relation to the accuracy of clocks. Effect of eccentricity of the earth's orbit, efect of inclination of the earth's axis, and combination of these two effects are considered. The accuracy of sundials is also discussed. (DH)

Describes an experiment designed to introduce physics majors to the triggered oscilloscope. The experiment uses an inexpensive, easily constructed generator which sends pulses down a long coaxial cable, thus providing useful waveforms. (DH)

Provides a method for correcting the photoemission from a collector when using the photoelectric effect experiment to determine Planck's constant. The problem results from a negative current through the cell and makes the measurement of the cutoff potential difficult. (DH)

Describes a laboratory activity which provides practical experience in wiring an electrical circuit with line voltage and everyday components. Students use wooden frames, bulbs, wire, fuses, and switches to test their wiring skills. (DH)