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acquire data in strains as the Strain and Pressure Measurement Laboratory, including strain

gauges, a Wheatstone bridge, a signal conditioning system, and an analog/digital converter.

2.2.2 Opportunities for Improvements and Expansions

Laboratories that measures pressure and vibration with strain gauges are frequently

taught at colleges. A review of the similar laboratories developed by other organizations provides

insights for the opportunities for improvements and expansions of the current laboratories at WPI.

More areas for improvements are suggested from a close examination of the current laboratories.

2.2.2.1 Design of Strain and Pressure Measurement Laboratory

The current set-up provides reliable measurements with an impressive micro-strain level

resolution, which is enabled by the 16-bit A/D converter and the signal conditioner. However,

the current laboratory does not fully utilize the set-up to reinforce the students’ appreciation of

resolution and the benefits of signal conditioning in the laboratories. The students can benefit

from additional activities to measure the resolution and noise under different gain settings and

the A/D converter’s range settings.

The current laboratory focuses on demonstrating pressure measurement with strain

gauges. The strain gauges are installed on soda cans, and once the cans are opened, the gauges

cannot be reused. Adding a few more activities to the existing laboratory could help utilize the

perishable materials more sufficiently. For example, an experiment conducted at Purdue

University College of Technology at New Albany proved that turning the can end to end twice

after shaking the can for 5 seconds will drastically reduce the measured strain in soda can

experiment. (Dues, 2006) The results from this experiment showed that the strain measured after

turning the can end to end twice is 90% lower than the strain measured directly after shaking the

can for 5 seconds. (Dues, 2006)

It is not uncommon for undergraduate laboratories to take advantage of a “class data

sheet” to increase the size of data set, which often provides more opportunity to practice the

statistical data analysis, and to draw significant conclusions to the phenomenon investigated. In

the case of this specific laboratory, multiple sources of errors exist in the strain gauge installation

process, such as alignment, surface condition of the adherence, wiring, etc. The property

measured, internal pressure of a soda can, can be easily affected by the person conducting the

measurement, as the solubility of carbon dioxide in the beverage can be affected as local

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