Under Pressure
Measuring atmospheric pressure over a 24-hour period.
Barometer Sensor (PS-2113)
Lab Summary
In this experiment, we will use the Barometer Sensor to measure atmospheric pressure over a 24-hour period. Students can then hypothesize reasons for any changes that occur.
Atmospheric pressure, measured by a barometer, is a ratio of the force of air to the area of the surface upon which it presses down. Due to the pull of gravity, 99% of the total mass of atmospheric gases is found within 32 km of the surface of the earth, and there is less air at higher altitudes. Atmospheric pressure at mean sea level averages approximately 29.92 inches of mercury (1013 millibars Hg or 760 mm Hg), which corresponds to 14.7 pounds per square inch of air pressure.
Barometric pressure is an indicator of incoming weather systems. Low-pressure systems often bring with them clouds and precipitation, because air rises in low-pressure systems. The higher the altitude, the cooler the air gets, causing condensation, clouds and precipitation. High-pressure systems usually result in mostly clear days. High-pressure systems push air closer to the ground, preventing the formation of clouds. In general if pressure rises, it’s an indicator of clear weather or improving weather on the horizon. If it is falling, it can be a prelude to cloudy or possible rainy weather. If it remains steady, expect more of the same of whatever the current conditions are.
Published: March 2002
Downloads
- Under Pressure - PASPORT (45 KB, .zip)
Includes experiment setup, procedures and Datastudio file
- Under Pressure - ScienceWorkshop (44 KB, .zip)
Includes experiment setup, procedures and Datastudio file
Here's What You Need
U.S. Educator prices shown.
Probeware (PASPORT System)
PASPORT Barometer/Low Pressure Sensor (PS-2113A) - $89
Measures atmospheric pressure changes and doubles as a low pressure sensor. For use with PASPORT Interfaces.
Xplorer GLX (PS-2002) - $349
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
Probeware (ScienceWorkshop System)
Barometer (CI-6531A) - $119
Designed to measure changes in atmospheric pressure over long and short periods of time.
750 Interface, USB (CI-7650) - $679
The 750 Interface allows students to measure force, temperature, pressure, angular velocity, acceleration, current, and magnetic field with a built-in function generator and oscilloscope mode.
