Describes an inexpensive tensiometer, a balance consisting of a plastic drinking straw as the crossarm, a needle as a pivot, and wire loop counter balance to assure proper balance. The instrument permits the quantitative demonstration of interfacial tension and effects of various agents that modify it. (Author/JN)

Presents an examination of the buoyancy principle which can serve as a simple but rigorous illustration of a falsification test that not only clears up a possible misconception but also points the way to a number of practical uses of buoyancy measurements that have not generally been recognized. (MVL)