Program 43 examines Albert Einstein's interest in perfecting the central ideas of physics. Details Einstein's new understanding of the meaning of space and time, including such matters as the transformation of velocities, time dilation, and the twin paradox. Program 44 deals with the formulation of a new mechanics based on Einstein's concept of space and time. Covers relativistic momentum, equations relating kinetic energy and total energy of a particle to its speed, and the relation between mass and energy in special relativity. Program 45 traces the ups and downs of scientific research as reflected in Boyle's experiments and Charles's investigations. New discoveries about the behaviors of gases make the connection between temperature and heat. Program 46 deals with the Carnot engine and the first law of thermodynamics. Uses computer animation sequences, historical reenactments, and close-up photography of experiments.