MyTech: Measurements using Everyday Technologies
The Paesler research team is currently developing a suite of laboratory experiments featuring the use of students' own electronic equipment in data taking and manipulation. They refer to the proposed program as MyTech for Measurements using everydaY TECHnologies. Beginning with available apps and later developing new ones, they are constructing laboratory instructions and procedures for a suite of laboratory exercises for college level general physics laboratories. The development of new apps will focus on creating simple applications with the capabilities needed in the experiments for which they are deigned without clouding their operation with unnecessary capabilities.
Possible Benefits of MyTech
When using devices with which students are familiar, process questions rarely arise about how to gather or analyze data. Video-capture and single frame analysis can be routinely undertaken with ease. (The technique is a modern offshoot of the video-based student laboratories pioneered by co-PI Beichner in the 1980s.) Time analysis of audio-captured events — while not a common capability prior to the laboratory — can be a quickly learned skill after simply downloading appropriate applications. Preliminary experience in a feasibility MyTech study demonstrated that the questions all-too-typically involved with conventional laboratory equipment were simply gone when the students' own personal electronic devices were at the student-data interface.
Both the operational and the attitudinal difficulties that a student must confront when undertaking a typical undergraduate physics lab can be inferred from the figure above where a typical computer screen from a simple mechanics laboratory is presented. Students are shown an image of the black box that serves a particular function in the experiment at hand. They must choose from a long list of capabilities to determine the function of the box — most of which are not of use to them and/or are opaque. (Of what use is an EKG in a physics lab!) Absent from the exercise are the genuine tactile actions of making real connections and operating specific devices. Perhaps most egregious is the distancing of the students from the equipment by the intercession of a black box and a tangle of computerized actions.
A second family of obstacles results if laboratories are simply not offered because the cost of data taking and manipulating equipment is prohibitive. Shrinking state support for public education and the current climate of austerity mean that some four-year institutions of higher education and many two-year colleges lack appropriate facilities to support teaching laboratories in what should be lab-based courses. (Carlson, 2012) While inclined planes, pulleys, pendula and other simple equipment may be with the means of such institutions, the cost of data interfaces used to record and process data may be beyond budgetary capabilities.
In conventional laboratory free-fall experiments a lucite picket fence is dropped next to a photo-gate. As the lucite passes through the gate, light pulses are recorded. The data are captured with a data interface and are then interpreted on a computer. Through several algebraic manipulations explained in the lab write-up, students are ultimately able to calculate the acceleration due to gravity. In a MyTech lab, students use an audio-capture app on their smart phones or laptops that allows them to simply and accurately record the time of a free-fall.
The differences between these two means of measuring the acceleration due to gravity, or g, are highlighted in the figure below. In one case with their smartphones and one simple app, students directly measure a distance and a time using everyday items. They then apply this to a concept and a simple equation they have confronted in their readings and in class as a simple kinematics expression. The result is a determination of g. With unfamiliar commercial equipment, on the other hand, students must use a black box interface to obtain data on a laboratory computer. The output is a table of numbers indicating when the successive pickets passed the photogate. Finally they are led through several algebraic steps before arriving at g.