Part 2, Harnassing the Elements, Introduction, Floating, Flying and Pressure Power, pp.91-141 Summary and Analysis

The introduction to Harnessing the Elements discusses the Greek's belief in four elements: earth, air, water, and fire. We know now that elements number many more than four, and that earth, air, water and fire are each built on a combination of two or more elements. An element is a substance which contains only one type of atom. Atoms combine to build molecules and Part 2, Harnessing the Elements, is actually about harnessing molecules, or rather the forces created by the molecules' strong urges to huddle together or spread apart. The reader will remember that in Part 1, while studying springs, it was explained that under normal circumstances molecules have an attracting force and a repelling force. When squeezed or stretched...