2. Weather Water Cycle: the continuous movement of water between the atmosphere, the land, and the oceans Evaporation occurs when solar energy heats water molecules, and they rise as gaseous water vapor. transpiration: the process by which plants release water vapor into the air through their leaves precipitation: any form of water that falls to Earth’s surface from the clouds

3. Weather Air Pressure The barometric pressure, also called atmospheric pressure or air pressure, is the pressure that results from the weight of a column of air extending from the top of the thermosphere to the point of measurement. Changes in barometric pressure often accompany changes in the weather.

4. Weather 〉 Differences in air pressure cause air to move creating winds. pressure gradient: a difference in air pressure from one place to another The air in a pressure gradient moves from areas of high pressure to areas of low pressure. wind: the movement of air from a high-pressure area to a low-pressure area

5. Weather Coriolis effect: the curving of the path of a moving object from an otherwise straight path due to Earth’s rotation Points at different latitudes on Earth’s surface move at different speeds. Earth goes through a full rotation in 24 hours. Points on the equator travel the Earth’s full circumference in 24 hours. Points closer to the poles do not travel as far.

6. Weather Predictable air circulation forms wind patterns. Winds in the Northern Hemisphere curve clockwise. Winds in the Southern Hemisphere curve counterclockwise. The resulting patterns are very regular, and have been named by meteorologists. Polar easterlies Westerlies Northeast trade winds Southeast trade winds