Explains and illustrates strange events which occur when two pendulums interact through a variety of interconnections. Phenomena addressed include: pendulums coupled by a spring, rod, or string; vertical and rotational oscillations, and synchronous and mirror-image swinging. A resonant-spring pendulum and a Wilberforce pendulum are also discussed.…

Presents a field formula for calculating speed and flight efficiency of soaring birds. By estimating the size of the bank angle and timing the complete circle, the observer can determine the speed and circling radius on a chart provided. Lift coefficients and flight characteristics of several birds are also discussed. (DH)

Discusses forces that shape the behavior of water as a drop meanders down a windowpane. A homemade apparatus for studying meanders is described along with several experiments. Contact angles, molecule attraction, surface area, air tension, and gravity drag forces are some of the topics addressed. (DH)