تسجيل الدخول

تسجيل

Atmospheric Pressure at Sea Level

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-172

2025-11-11

526

The average height at which the mercury column stands, at the level of the sea, is 76 cm., and this height is independent of the diameter of the tube. If the area of the cross section of the tube is 1 sq. cm., the volume of the mercury will be 76 c.c., and since its specific gravity is 13.596, its weight will be 1033.3 g. In English measure the average height of the column is 30 in., and if its cross section is 1 sq. in., its weight will be 14.7. lb. Since this weight is the measure of the pressure of the air, we can state the following:

The average pressure of the atmosphere at sea level is 14.7 lb. per square inch, or 1033.3 g. per square centimeter. This is called a pressure of 1 atmosphere, and as it is constantly changing, it is often called in round numbers 15 lb. per square inch, or 1 kg. per square centimeter.