1. Barometric Pressure Ms MacInnes Science 10 2013

2. Barometric pressure  aka Air pressure: caused by the weight of air molecules above  Air pressure is related to density which is related to air temperature and distance from the earth

3. High Pressure  Causes air to flow down and fan out  Moves clockwise in the Northern hemisphere and counter clockwise in the Southern hemisphere (due to the Coriolis effect)  Tends to cause clear skies because sinking air prevents clouds from forming  Associated with clear, cold/cool weather

4. Low Pressure  Causes air to flow up  Air cools as it rises.  Water vapour is unable to remain a gas  Water droplets form, making clouds  Low pressure is associated with warm, rainy, cloudy weather