World's Tallest Barometer, an Educational Lab Apparatus

The barometer has been around since the early 1640's when Italian scientists Berte inadvertently made a water barometer and Torricelli purposely made a mercury barometer. A water barometer has the problem of high vapor pressure, so that it does not maintain a good vacuum above the water column unless continually vacuum pumped. The high density of mercury and its low vapor pressure allows a mercury barometer to be a compact and accurate lab apparatus. The newly being built barometer at Portland State University's Maseeh College of Engineering atrium makes use of doubly distilled synthetic vacuum pump oil as the working fluid. The fluid has a specific gravity of 0.83 and very low vapor pressure. The nominal height of this barometer is expected to be 12.4m. This barometer will be used in the Civil Engineering Fluids Lab as a lab apparatus and the reservoir has the capability of being pressurized or depressurized artificially, so that the fluid column can be manipulated and measured by the lab students. With the placement of the tall barometer in the atrium of the Engineering Building, the barometer will be visible to the public and to touring student groups.