Describes a demonstration using a heated wire to illustrate the phase change from the body-centered cubic form of iron to the face-centered cubic form. (MLH)

Scientists often use the "slingshot effect" (also called the "gravity assist") of the gravitational field of a planet to increase or decrease the velocity of a spacecraft. Examples of this effect, puzzling aspects, a qualitative explanation, details of necessary calculations, a thermodynamic analogy, and other topics are discussed. (JN)

An experiment is described in which students in an introductory laboratory can determine all of the relevant energy flows of an ordinary household refrigerator. (Author/CP)