Pressure
When the wind blows we can feel the force it has on us. However, when the air is still we do not notice the downward pressure that it exerts on the Earth's surface. In fact, air pushes down on everything lying on the Earth's surface with a force of 14 pounds or 6 kg per square inch. We do not feel this atmospheric pressure because the pressure inside our bodies is equal to it.
Because gravity pushes air towards the Earth's surface, it is thinner the higher one rises, and consequently atmospheric pressure falls. Atmospheric pressure at the top of Mount Everest is about a third of that at sea level. Weathermen measure atmospheric pressure with barometers, which show pressure in millibars. Usual sea level pressure is close to 1000 millibars.
Print Topic
Websites
Other topics
Technical Page
• Wild Weather Page
• Infoplease.Com
• NASA Earth Science
• Introduction
• Air
• Air Layers
• Clouds
• Meteors
• Moisture
• Pollution
• Pressure
• Temperature
• Weather
• Wind