Physics C Mechanics

Video Lab: Measurement

If you are taking this course through PA Homeschoolers, you must submit this lab report.

Before performing this lab you must read through the previous assignment in the unit 1 workflow titled Overview: Course Information detailing the nature of science and the lab notebook requirements. You must also take the quiz at the end of that assignment.

The video below will allow you to make timing measurements on a device known as an inertial balance.  The inertial balance will illustrate an important idea that we will discuss extensively in this course: The more mass something has, the harder it is to change its state of motion.  Your goal in this lab is to create a graph that will allow you to determine the mass of an unknown object using the inertial balance.  To accomplish this goal you will need to make careful observations of the apparatus in the video.  You will need a stopwatch to make these measurements. Almost all mobile phones come with a stopwatch function, so please make use of it for this lab exercise.
When you are ready to start, play the video and follow the instructions as given.  Please record all your work in a lab notebook. Use this structure:
1. The title of the lab activity
2. The date the lab activity was performed
3. The goal(s) of the lab activity
4. A description of the lab activity (procedures, sketches, pictures, etc.)
5. Data collected in the lab activity
6. Analysis of data and sample calculations
7. Analysis of error (In this lab calculate the percent error between the unknown mass you calculated and the actual value given in the video)
%Error = [(actual – measured)/actual] x 100%
8. Conclusion(s) (Summarize your findings and answer the following "What if?" question: If your stopwatch systematically undermeasured the time for the oscillations how would that have affected your calculation of the unknown mass? For example, if your measured times were all 0.3 seconds short would you still arrive at the same unknown mass? Perhaps create another data table and do a second analysis to find out. Explain your findings.)

Note: When you create the graph for this lab report, consider using spreadsheet applications like Google Sheets or Microsoft Excel to plot the data (a scatter plot) and add a line of best fit (a trendline). If you are unfamiliar with these applications, here are links to short videos (less than 5 minutes) that provide detailed instructions: