Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Problem with a Barometer



Hi,

I have an odd problem with a mercury barometer. It
reads too large of an atomospheric pressure. Here at the U
of AZ the Atmospheric Science Dept has two nearby stations
from which I can get readings. These report something like
27.2 inches ( NOT corrected to sea level) and I get 29.5
inches.

I checked the scale using a meterstick and two agree
to within a millimeter which is the error in my reading of
the meterstick. I have checked for bubbles or breaks in the
mercury column but there are none visible. The tube is
large enough the the correction for capillary effects is to
be small and the correction is in the wrong direction. Air
in space above the column would also cause an offset in the
wrong direction.

I am baffled and will probably just replace the
mercury during the summer.

Thanks
Roger Haar