Wind

The world's atmosphere is forever on the move. The wind is air in motion. Sometimes air moves slowly, giving a gentle breeze. At other times it moves rapidly, creating gales and hurricanes. [blank] or fierce, the wind always starts in the same way. As the sun moves through the sky, it heats up some parts of the sea and lands more than others. The air above these [blank] spots is warmed, becomes lighter than the surrounding air, and begins to rise. Elsewhere, cool air sinks, because it is [blank] . Winds blow because air squeezed out by sinking, cold air is sucked in under rising, warm air. Winds will blow wherever there is a [blank] in air temperature and pressure, always flowing from high to low pressure. Some winds blow in one place and have a local name - North America's Chinook and France's Mistral. Others are part of a huge circulation pattern that sends winds over the [blank] globe.