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Physics 300 - Teacher's Notes

This lab is meant to provide a problem solving approach to data analysis. Be a guide and resource during the design of the cars. Allow the students to attempt different designs, even if the design may not work properly. The students need to find out what does and doesn't work on their own. Encourage students to investigate different designs. Also point out to groups how the knowledge of design strategies that work affect the design of their cars as well as the others.

During the data collection of the lab, remind students to change both the angle of the incline as well as the mass on the car. Also remind them that the analysis of the car's motion should be done once the car is off the ramp. The car should have a relatively constant velocity during the data collection period.

During all parts of this lab, be prepared to answer a lot of questions. Most students are not used to this type of lab. Some may not know where to start. They may become frustrated. Encourage them to talk about the design with the group, this usually helps. Be cautious as to how much you tell the students regarding the design of the car. If possible question the student about what he/she thinks or how a certain decision will affect the performance of the car.

The data collection for the trial runs should be done using Logger PRO® and the motion detector for the ULI. The experiment file for the Average Velocity lab will provide the data collection features needed for this lab. Although it would be nice to use the Logger PRO® to analyze the data, the data recorded includes some time in which the car has not yet been detected by the motion detector. This extra data is used when computing the regression line in Logger PRO®, giving the wrong answer for the constant velocity. Instead, students should choose ten points throughout the experiment that represent the car as it rolls across the floor, enter this data into the TI-83®, graph it and determine the slope of the "best fit" line. This slope will be the car's average velocity as it moves across the floor. If several TI Graph Links® are available, the students can use them to print out the data lists and the graphs from the calculator.

Another option for the analysis of the data is the use of Graphical Analysis® software from Vernier Software. Students can export the data from Logger PRO® and import it into Graphical Analysis® which will allow them to delete the data prior to the car being detected. Graphical Analysis® can then show the regression line as well as the slope of the line. The program can also print out the data tables and graphs as needed.

Either method that is used should follow a few trials in which the students draw their own graphs and "best fit" lines. These trials can then be checked using the methods above. This will easily show the student the accuracy of the graph and regression line that they have chosen. This helps insure that the student understands the concepts and mechanics of determining the "best fit" line.

After the project is completed, lead a discussion regarding the design process of the different teams. Allow teams to explain the design of their car to the other teams. During this discussion, try to point out the connection between the group's knowledge of what worked and the integration of that "technology " in their design.

Remember, this project is intended to give the students practice at problem solving. It's their problem to solve, not yours.

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