Air has weight. You cannot feel the weight of air, but all the air in the atmosphere presses downward. This weight is called atmospheric pressure. Atmospheric pressure depends on how much gas is in the atmosphere. The higher you go, the less air there is and the lower the atmospheric pressure gets. The atmosphere is heaviest and the atmospheric pressure highest close to Earth. Differences in air temperature close to Earth form areas of high and low pressure. Warm air is light and rises upward. It makes low-pressure areas. Cold air is heavy and sinks. It makes high-pressure areas.WEATHER AND THE ATMOSPHEREAir in the atmosphere is always moving. You can feel air blowing on your face. You can see air scattering autumn leaves and making tree branches sway. Moving air is called wind. The wind blows where areas of high and low atmospheric pressure meet. As warm air rises, cold air rushes in to take its place. Big areas of high and low atmospheric pressure cause storms. Thunderstorms often occur where big areas of high and low pressure come together. Huge thunderclouds form in these places. Water vapor in the atmosphere makes clouds. Water vapor is a gas. As the gas cools, it turns to liquid water. The water falls to Earth as rain or snow.
No comments:
Post a Comment