Vernier Turns Up The Pressure with the new Pressure Sensor 400

The new Vernier Pressure Sensor 400 is one small step up in price, but one giant leap in performance. With an exceptional operational temperature range, and secure metal fittings makes the Vernier Pressure Sensor 400 is a serious tool for high school and college experiments in chemistry, biology, physics, and environmental science.

The earlier version of the pressure sensor had a few limitations that kept it from fully supporting the more advanced needs of the science learning community. For one, it was sensitive to certain caustic chemical vapors that could destroy its fragile pressure sensor membrane. And second, it’s range limited it to those pressures between zero and an average car tire.  

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The Pressure Sensor 400 has a much more durable membrane, and it has twice the effective range moving from that of a car tire up to a mountain bike tire.

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Pressure, or a perpendicular force per unit area is commonly measured in kilo-pascals such as with this sensor. At 400 KPa, the Vernier Pressure Sensor 400 works well within the safety considerations of science teachers.

However, there is a subset of material science that considers pressures of mindboggeling proportion. For instance the current world record for laboratory-created pressure is about 770 Gigapascals (GPa) or about twice that of the pressure you would find at the center of the Earth. And needless to say, things get pretty weird at those pressures such as “interplay” between the core electrons in atoms. For reference, it only takes about 24 GPa to make a diamond, or about 1/32 the pressure of the world record.

High Pressure

Compared to the previous (and still current) pressure sensor, the 400 looks and feels like a tank. The Sherman variety. Wearing two rubber rings for texture, and an overall ergonomic flavor, the 400 feels like a solid tool that will stand up to hard use much better than the plastic box of the general Gas Pressure Sensor. Which is exactly the point. Under some experimental conditions, the previous pressure sensor succumbed to corrosive vapors, and leaks in the seals. As a pressure sensor, the system with under inspection along with the sensor must remain completely closed. Any leakage along the way will produce faulty data.

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Been There…almost

The regular Gas Pressure Sensor by Vernier costs about one hundred dollars less than the new Pressure Sensor 400. $106 to be exact. In addition to twice the range, and twice the accuracy, the mechanical upgrades to the Pressure Sensor 400 over the other model include a brass tube connector, a push-to-connect connector made of nickel-plated brass and similar to professional plumbing fixtures, heavier PVC tubing, and included ridged nylon tubing.

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And the accessories of a metal wrench to ensure a tight fit, and thread sealing tape made of polytetrafluoroethylene (PTFE) or Teflon™ tape. Some call this white ribbon-like material “Plumber’s Tape” but the usual lexicon for plumbers tape indicates galvanized steel strapping material a few centimeters wide and filled with holes.

plumberstapeThis type of metal plumbers tape is is used to secure pipes and duct work.

And there is the heavy duty build quality of the 400.

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For comparison, the new 400 sensor measures pressures twice as great as the regular model. But to make the jump up to world record measures of pressure, Vernier would need to up their game and produce a sensor that could handle pressures two million times greater than the current 400 can deal with. And those pressures are most likely outside the safety limits of all classrooms as well as many planets and every comet, asteroid, and moon in the solar system.

Performance Under Pressure

The Pressure Sensor 400 also utilizes a heavy duty PS2 series pressure transducer from Honeywell. Similarly the regular gas pressure sensor uses a Honeywell sensor, but low pressure piezoresistive silicon-ceramic sensor.Honeywell PX2

The limitations of the lesser sensor is not usually a problem in educational applications where only non-corrosive dry gas pressure is measured, but when the chemistry or biology takes on a more potent smell, a more durable sensor is needed.

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The Pressure Sensor 400’s piezoresistive is contained within a stainless steel housing. The advanced design also provides much more shock and vibration resistance. A added factoid that I found interesting when researching this sensor is that its rated for a minimum of 10 million cycles to operating pressure.

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Here are three experiments using a pressure sensor and the LabQuest2.

790px-BernoullisLawDerivationDiagram.svgThe increased accuracy of the 400 over other pressure sensors comes in handy when experimenting with subtile pressure changes such as with low-speed measurements of the Bernoulli Principle. For example, at 80 kilometers per hour (~50 miles per hour) the the pressure difference between the relatively still air inside a car with the moving air outside the car window can be measured by taking pressure readings inside and outside the car using a tube connected to the Pressure Sensor 400. The lowest reading was -0.4k
Pa. In this inspection, the Pressure Sensor 400 was zeroed inside the car, and then a tube was slipped outside the car through a window and held perpendicular to the car’s direction of travel.

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When working with small values, the degree of accuracy of the sensor might also be the limits of the measurable data. 

Boyle’s Law is another easy target for the pressure sensor, as is Charles’ Law.

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Using the Vernier Go Wireless Link with the Pressure Sensor 400 offers additional freedoms for pressure measurements by reducing the number of digital connections and/or increasing the distance between computer and sensor. 

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So given the number of creative and innovatively explorative experiments that the regular pressure sensor has generated, the new Vernier Pressure Sensor 400 will again expand the potential for exploring the intriguing world of pressure.

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