The major philosophical shift in the idea of selling came when industrial societies became more affluent, more competitive, and more geographically spread out during the 1940s and 1950s. This forced business to develop closer relations with buyers and clients, which in turn made business realize that it was not enough to produce a quality product at a reasonable price. In fact, it was equally essential to deliver products that customers actually wanted. Henry Ford produced his best-selling T-model Ford in one color only (black) in 1908, but in modern societies this was no longer possible. The modernization of society led to a marketing revolution that destroyed the view that production would create its own demand. Customers, and the desire to meet their diverse and often complex needs, became the focus of business.

Along with evaporation and condensation, precipitation is one of the three major parts of the water cycle. Precipitation refers to any liquid or frozen water that forms in the atmosphere and falls back to the earth. It occurs in many forms, including rain, sleet, and snow. Precipitation takes shape within clouds as water vapor condenses into progressively larger droplets. When the droplets are heavy enough, they descend to wards the earth. In colder cloud temperatures, such as those found at higher altitudes, the water droplets may freeze to form ice. These ice crystals then fall as snow, hail, or rain, depending on the temperature both within the cloud and at the Earth's surface. Most rain actually begins as snowflakes high in the clouds. As these snowflakes fall through warmer air, they melt and transform into raindrops.