Mathematical puzzles are not usually associated with entertainment. However, the Rubik Cube continues to amaze, confound, and entertain. On this program, Tyson Mao discussed solving the Rubik Cube.

What is the appropriate market mechanism for moving away from a fossil fuel economy? On this program, Lester Brown from the Earth Policy Institute discussed how carbon taxes could better represent the true cost of energy.

Morality often is considered a sociological issue. However, recent advances in neurobiology are demonstrating that human brains are innately constructed for morality. On this program, Prof. Marc Hauser from Harvard University discussed the biology of morality.

Pets often perplex their human companions with their eccentric behavior. On this program, Dr. Marty Becker discussed the intricacies of pet behavior.

Bubbles created via the process of cavitation have many applications. On this program, Prof. Christopher Brennen from Caltech discussed the physics of cavitation.

The sources of emotional pain are wide and varied, but are firmly rooted in the deepest centers of the brain. Treating such mental anguish thus requires accessing these deeply ingrained structures. On this program, Drs. Arthur and France Janov discussed Primal Healing.

The problem of evil has confounded philosophers and scientists alike. Is there a biological basis for evil? On this program, Prof. David Buss discussed the biology of evil.

The work of Poincare on the three-body problem later became the framework for studying chaotic systems. Since then, mathematicians have made progress in these and other dynamical systems. On this program, Mason Porter talked about exciting developments in this field. Travis Heime also discussed condensed matter physics.

Environmentalists have been concerned about pollution in the sea and the depletion of fisheries, but are these worries overblown? On this program, Stacey Viera of the National Fisheries Institutes, explains the health effects of mercury and NOAA work in promoting sustainable fishing.

Scientists estimate that one-third of today's increase in greenhouse gas emissions come from changes in the land-use. One way to sequester the carbon emissions is plant more trees but are other crops better suited? On this program, special correspondent Terry Yen talks about the promise of anthropogenic peat.