Barometers
Barometers
Barometers are instruments that measure the pressure of air in a specific environment; barometer measurements are used to forecast weather and measure altitude.
Atmospheric pressure also depends on the planet’s mass, its surface radius, the gas concentrations and composition, and the gases’ vertical distribution in the atmosphere. It is also affected by the planet’s rotation and other local conditions including wind velocity and temperature-dependent density and gas composition variations.
Common pressure units include:
- Pounds per square inch (psi)
- Dynes per square centimeter
- Newtons per square meter (equivalent to the pascal, the SI unit)
- Inches, centimeters, or millimeters of mercury
- Millibars (1 millibar equals 1,000 dynes per square centimeter, 100 pascals, or 0.75 millimeters of mercury)
The pascal (Pa) or kilopascal (kPa) has worldwide use as a unit of pressure and has mostly replaced the unit of pounds per square inch. Exceptions are countries that use the imperial measurement system or the U.S. customary system.
In general, better or drier weather is indicated by a rising barometer; a falling barometer indicates worse or wetter weather.
Several types of quantitative or semi-quantitative barometers exist. Torricellian or mercury barometers use a column of mercury to balance atmospheric pressure. The height of the mercury is pre-measured, and the change in height is used to calculate the atmospheric pressure.
Nonliquid or aneroid (dial) barometers are used in portable instruments and aircraft altimeters because their smaller size offers convenience. A flexible-walled evacuated capsule moves with changes in atmospheric pressure – the movement mechanically moves an indicating needle. Recording aneroid barometers are called barographs.
Digital barometers contain a pressure transducer that converts the air pressure into an electrical signal.
Fisherbrand™ Traceable™ Handheld Digital Barometer
Keep track of your environment and your time with this multi-functional handheld barometer. Fisherbrand Traceable Handheld Digital Barometer measures and digitally displays temperature, altitude and barometric pressure.
Fisherbrand™ Traceable™ Precision Dial Barometers
Ideal for monitoring weather changes or environmental conditions in labs or plants
Fisherbrand™ Traceable™ Digital Barometer
Perfect unit for plants and labs to monitor barometric pressure, temperature, relative humidity, barometric pressure trend and time-of-day. Fisherbrand Traceable Digital Barometer is ideal for use in environments where there is a need to monitor conditions of environmental air parameters.
Oakton™ Aneroid Barometer
Monitor barometric pressure with these wall-mount barometers.
Digi-Sense™ Precalibrated Humidity and Temperature Indicators
Designed to gauge proper humidity levels
Fisherbrand™ Traceable™ Hand-Held Digital Barometer
Barometer, altimeter, thermometer, stopwatch and time of day clock — all in one.
Fisherbrand™ Traceable™ Digital Barometer
Perfect unit for plants and labs to monitor barometric pressure, temperature, relative humidity, barometric pressure trend and time-of-day. Fisherbrand Traceable Digital Barometer is ideal for use in environments where there is a need to monitor conditions of environmental air parameters.
Vernier Vernier Barometer
Measures and monitors atmospheric pressure.
Eisco™ Aneroid Teaching Barometer
A high quality teaching barometer to demonstrate operation. The exposed aneroid shows the change in barometric pressure when the attached bulb is pumped.
Swift™ Altimeter/Barometer
Visually demonstrates the connection between altitude and atmospheric pressure to help your students understand this relationship.
GSC Go Science Crazy Weatherball Barometers
Predicts barometric pressure.
Fisherbrand™ Traceable™ Workstation Barometer with Clock
Ideal for recording ambient changes in the lab, monitoring conditions affecting sample analysis and assisting in the prediction of weather changes
H-B Instrument™ Durac™ Barometer
Recalibrateable unit
H-B Instrument™ Durac™ Thermometer-Hygrometer-Barometers
Recalibrateable instrument
H-B Instrument™ Durac™ Weather Ball Barometers
Enables you to predict weather conditions with respect to water levels.
Fisher Science Education™ Junior Barometer
Features a plastic case, dual-scale black markings, white dial and a movable pointer to observe direction and amount of change as it occurs.
Fisherbrand™ Computer Data Acquisition System for Digital Barometer
Keep track of results for thermometers, hygrometers, barometers, light meters, anemometers, manometers, dissolved oxygen, conductivity and more. Fisher Scientific™ Computer Data Acquisition System for Digital Barometer is for use with Fisher Scientific™ Traceable™ Digital Barometer.
Bel-Art™ SP Scienceware™ Weatherball Barometer
Accurately predicts weather conditions.
H-B Instrument™ Wireless Weather Station
Become an amateur meteorologist with these all-in-one wireless stations.