A series presenting science as a detective story illustrating the connections between events of the past and inventions of the future. Part 5: Traces the connection between medieval astrology, ancient Greek medical manuscripts, the need for precise measuring devices and the invention of such things as the telescope, forged steel and interchangeable machine parts. Part 6: Details many of the changes in building construction and energy usage which occurred when the climate of Europe changed dramatically in the 13th century. Shows how the scarcity of firewood contributed to the invention of the steam engine, which was the predecessor of gasoline-powered engines.