analogue methods of measuring pressure

Main Issues :

-Change in pressure -----> change in material (expanding/contracting, bending)

-Change in pressure -----> changes sealed gaseous liquid (aneroid device), liquid (alcohol, water, oil, mercury)

-Scale enlargement

Need to address:

Pressure Differential

Deflection

Air/Gas/Liquid expansion

Aneroid Barometer (Leibnitz 1844)

(means without water/liquid)

an=without

aer (air)

eidos (form)

-capsule device that moves with changes in pressure (an alloy of beryllium and copper)

-when the air has been partially removed from the box the surface depresses or expands with variation of air pressure on it.

-increase in atmospheric pressure increases air density

-expansion or contraction of the vacuum chamber is caused by change in air pressure

Article "Remote query pressure measurement using magnetoelastic sensors"

-inexpensive sensors

-no internal power supply

-remote query sensing of environmental parameters

Hanging Water Experiment

-the air around us is always pushing against something - it pushes in every direction

-the greater the air pressure pushing on the nylon/paper/silicon/vinyl is greater than the pressure of the weight of the water ie. air pressure.

http://www.elmhurst.edu/~chm/vchembook/180pressurefs.html

Denis Dingens article "Weatherinstruments" discusses the invention and development of different types of barometers and calibration of barometers for various sea levels.

http://www.barometers.com/images/meteo_english.pdf