16.1 Water circulates through the hydrologic cycle (水文循环) The Earth's water is constantly circulating, powered by the heat of the sun and the force of gravity. Water evaporated from ocean precipitates(降水) into the ocean: direct route. Water evaporated from ocean is blown by winds until it is over the land and precipitates: (1) evaporates beck into atmosphere, (2). Infiltrate
8. 1 Water molecules form an open crystalline structure in ice When water freezes. the water molecules arrange themselves in a six-sided crystalline structure. Increased structural orderliness usually means increased density. Solids and crystals have high structural orderliness and are thus denser than liquid and non-crystalline materials. But water is exception