Vertical Profile of Pressure

  • Atmospheric Pressure:

consider a column of air 1 inch2 in size extending from sea level to the top of the atmosphere.

the weight (=mass X gravity) of the column of air will be about 14.7 lbs.

Hence, the pressure at sea level is = force/area = 14.7 lbs/inch2

Sea-level pressure is also given in other units:

  • 14.7 lbs/inch2
  • 1013.25 millibars
  • 1013.25 hPa (hecto Pascals)
  • 29.92 inches of Hg

Questions for thought:

How heavy would I have to be to exert sea-level atmospheric pressure by standing on you on one foot?????

Which exerts more pressure, a 4000 lb elephant standing on one leg with a foot size of 8" x 8" or a 120 lb woman standing on one leg in high-healed shoes with a heal size of 1"x1"?