## Physics Education Research and Development Group |

# Why Computers?

- Computers can lead to faster, more accurate data acquisition and analysis
- Allow for a greater range of data gathering and analysis techniques
- Familiar technology for most students.
- Computer literacy is essential for students, especially those pursuing technical fields (such as engineering).

One concern to address: the computer should not detract from the physical phenomena being studied.

# Why video?

- Can capture two-dimensional motion
- Less abstract (see motion of objects replayed in a video)
- Familiar technology (even cell phones, digital cameras, etc. can capture videos)

# Why design our own software?

The software is designed to reinforce the pedagogy of problem-solving labs and cooperative group problem solving - it facilitates discussion within student groups and coaching by a TA. Features of the software are intended to prompt specific decisions, such as:

- Predict an equation before plotting data
- Explicit calibration process
- Choose a coordinate system; select the origin and rotation, if applicable
- Manually plot data by advancing video frames and moving a cursor
- Analyze (fit) video data by selecting an appropriate function and editing coefficients
- Axes are unlabeled
- Limited "go back" or "undo" functionality.

# Why LabVIEW^{TM}?

- Many departments already own and are familiar with
LabVIEW
^{TM}. - Graphical programming allows for easier adaptability by instructors.
- Industry standard and continued support.

## How are computer-based labs used at the University of Minnesota?

Our computerized labs use the same
**cooperative group problem solving** techniques
that our traditional labs do. Cooperative group problem solving involves
students working in groups of three students on specifically designed problems.
We use five main ideas to promote effective cooperative grouping:

- Students must have some reason to work together - positive interdependence.
- Students should work face to face and knee to knee, not lined up in a row.
- Students should not be able to piggyback on the work of others - individual accountability.
- Students should have (or be learning) skills that allow them to work with others.
- Students should have time to assess their group functioning skills so they can work to improve them.

It is not enough to just group students and follow these guidelines. They must also be assigned tasks appropriate to the group environment. A problem which is too simple will encourage students to solve it individually rather than with their group. A problem which is too difficult will lead to frustration and group fragmentation. We have a pool of carefully designed context rich problems for use by groups. Students work on these problems both in recitation and lab.

The computer lab problems are very similar to our traditional lab problems, and the structure of the lab remains the same. The only difference is the manner in which students collect data and analyze it to solve the lab problem. We chose to create our own software for our labs. A major reason for this was to maintain the pedagogical structure of the lab. Students are given a problem. Then they are given the tools necessary to solve the problem. The computer is one of these tools. They design and execute a method for solving the problem, using the computer if it is appropriate to their solution method.

We chose to use a video capture and analysis system for data collection and analysis of motion. In other types of labs we use the standard commercially available Vernier probes with a LabPro interface. Groups use this software with small, durable cameras to take movies of carts rolling on tracks, accelerating hanging masses, blocks sliding down ramps, thrown or bounced balls, rotations, and other motion-based phenomena.

The software does not do the analysis for the students. Instead, the software guides the students through several phases important to problem solving. For example, if students are investigating the motion of a cart traveling down an inclined plane, first they predict what the particular motion they are studying will look like on a graph, picking the proper equations and coefficients to match their prediction. Then the students open their movie in VideoTOOL, calibrate the scale, choose axes, and set the time = 0 point. After the calibration is finished, students collect data by advancing video frames and following the object on the screen with the mouse cursor. Data is plotted by the computer, as it is gathered, on the graph which also displays their prediction. Once the data collection is over, students compare their prediction to the data, and determine the functional form of their data by selecting an equation and coefficients as in the prediction. Students are next asked to predict the functional form of the velocity graph. Then the program analyzes the position data and plots the velocity data on the graph with their prediction. Students then determine the functional form of the velocity data, and then determine the acceleration and compare it to their prediction. The graphs are printed out or saved as a pdf document for the students to review and use in their lab reports. The document includes both predicted and fitted values for all graphs.

# PER

# Comp. Problem-solving Labs:

- Home Page
- Frequently Asked Questions
- (Old) Pictures of our labs
- Laboratory
Manuals from the

Problem-solving Labs section. # FAQ Contents

- Why computers?
- Why video?
- Why design our own software?
- Why LabVIEW
^{TM}? - How are computer-based labs used at U MN?