# Discovering Velocity Outside of the Classroom

Initial Publication Date: September 26, 2007

#### Summary

In this teaching physics with data based activity, the students gather data as a class from a person running at different rates on a football field. Synchronizing stopwatches and placing students every 10 yards apart as a classmate runs down the field and data is collected. The students then share the data as a class and transfer it to any graphing program. Once graphed, the entire class has the exact same distance versus time graph. As a class we then discuss what was happening between various time intervals, record in words what the graph is showing, and calculate average velocity.

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## Learning Goals

Concepts:
The student will learn the concept of the importance of accurate data collection.
The student will learn the concept of creating a distance versus time graph.
The student will reinforce the concept of converting yards to meters and minutes to seconds.

Vocabulary Words:
velocity
average velocity
instantaneous velocity
distance versus time graph

Higher order thinking skills:
data analysis

Other skills:
Observation
Data collection
Proper use of a stopwatch
Factor-Label method of converting

## Context for Use

Class size - larger than 11
Educational level - 9-12
Instruction Type - field exercise, lab, lecture
Time - 3 50mn class periods
Instrumentation - marked field, stopwatches (11)
Prior Knowledge - graphing programs (Excel), division, slope, conversions, speed

## Description and Teaching Materials

I do little to introduce this activity other than let them know we are going outside. Before I bring them outside I teach the students how to properly use a stopwatch, discuss the idea of synchronizing, split them into 11 groups, and designate a runner. We then go down to the painted football field and synchronize the stopwatches. Each group goes to their assigned yard marker (0-100 yards) and is instructed to stop the watch when the runner passes their marker. The students are then required to record that time and contribute their data to the class data. Once the experiment is completed outside, the students then return to the classroom where they place their yard maker and time recorded on the board. Their homework overnight is to convert all of the yards into meters, discuss the importance of the first time recorded (this is the 0), and calculate the time at each yard marker. When they return the next day we go over, as a class, what values they should have obtained. We then take the period to go to the computer lab to plot their data into a distance versus time graph using Excel. The entire class then has the exact same graph in which data analysis can be done. On the third day I have an open style lecture with the class describing what we did, why we did it, and what we can do with it. This brings in analyzing, using words, a distance versus time graph and calculating average velocity. Once the activity is completely over it has provided an excellent segue into acceleration.

## Teaching Notes and Tips

1. Students may have a difficult time understanding synchronizing, be patient. To synchronize stopwatches have all of the students with stopwatches gather around and have them all start their stopwatches at the same time. They leave it running until the runner reaches them. The stopwatch is then stopped. The students have to subtract the time from the person that stood on the goal line from their time to get the actual time it took to reach that point.
2. You may have to send the runner 2 or 3 times before the class actually understands when to stop their stopwatch.
3. If a football field is not available any marked off area will work.
4. When graphing in Excel many students will need help. I commonly walk them through the graphing portion. They are allowed time to tinker with the graphing program and are able to compare the graph to their hand made graph on paper. Graph as a scatter plot that is connected between the data points. Distance should be on the y-axis with time on the x-axis. Be sure to add an appropriate amount of grid lines for accurate calculation of average velocity (slope) the following day.

## Assessment

The students are assessed on this project during the chapter exam and the final exam. They are to write what is happening on a distance versus time graph and calculate various average velocities using the same graph. As for collecting the materials, I do very little, we go over all of it in the classroom and they correct as they go. I check to make sure they completed the project.

## Standards

I.B.2 - qualitative v. quantitative
I.B.3 - math and models
I.B.4 - error