Cycles of Change

The Geographic Gateway A map of North America shows tall mountain ranges on the eastern side, standing between the ocean and the flat interior continent. Rivers flow down from these mountains, but most travel only east or south, which provides little help for travelers moving west. Central New York [...]

There is a common idea in economics that says humans are so creative and adaptable that we will always find a way around scarcity. When something runs low, the price rises, people innovate, and a solution appears. This has been true in some cases. But there are limits that human ingenuity cannot [...]

Efficiency in human-powered transport depends on moving energy from the legs to the ground through a mechanical interface. Early bicycles used a direct-drive system where the pedals were attached to the front axle. This creation resulted in a massive problem for the rider because travel speed was [...]

In the 1960s, bicycles looked similar to modern bikes but functioned quite differently. They had two wheels, pedals, and handlebars, yet lacked the sophistication of current designs. Bicycles were simpler machines with fewer gears. The drive train, consisting of the chain, gears, and derailleurs [...]