This sensor measures the differential pressure between its two ports. If one port is open to the atmosphere then the sensor measures pressure relative to the atmospheric pressure. With both ports open to the atmosphere, the reading is 0. Blowing into one port will produce a positive value, whereas blowing into the other port will produce a negative value.

This sensor has a very sensitive range and is suitable for a number of Biology experiments e.g. as a manometer, investigating the uptake of oxygen by maggots or breathing rate.

For breathing rate investigations use this sensor connected to a Breathing rate belt - see the 3190PK Breathing Rate Belt and Pressure sensor pack. 

Applications

Biology:

• Experiments involving a Manometer
• Breathing rate (used with the Breathing Rate Belt 3190)
• Production of gases in an enclosed atmosphere (O²) during photosynthesis of an aquatic plant
• Osmosis investigations
• Rate of Transpiration investigations

The Differential Gas Pressure sensors have 2 ports. 

The external diameters of the ports are tapered from 4 to 4.3 mm.

The sensor element has automatic internal temperature compensation so that changes in room temperature do not affect readings

The user manual (available from the Resources tab) has a recommendation chart for the ‘best’ sensor to use for different gas pressure investigations.

A Gas Pressure Tubing Accessory pack (3138) is available which contains PVC tubing, pipettes, connectors, stopcocks and a syringe.