|PH111L - Physics I Lab|
Fall Term 2014
Instructor: Galen C. Duree Jr., PhD
Office: Room DL102 Phone: 872-6025 Box: 182
Office Hours: 9:30 AM - 11:00 AM T Th & 4:20 PM - 5:15 PM M T Th F
The third series of experiments, entitled "The Simple Pendulum" (a description of which can be found in the lab manual beginning on page 82), will be performed in BL113 this week.
The lab reports for the "The Simple Pendulum" experiments are due in the green bin outside my office by 5:30 PM, one week after you performed them in the lab.
Section 52 will meet at 8:05 AM on Monday, Oct. 27.
Section 53 will meet at 8:05 AM on Friday, Oct. 31.
For this experiment, the purposes are to evaluate the model for the period of motion of a simple pendulum and determine if mechanical energy was conserved in one of your experiments. Include one sample graph of θ vs. t in your procedure section and include a graph of θ vs. t with a sine curve fit in your analysis section. Unlike the procedure described in the lab manual, I think it is much easier to analyze the data using the sine curve fit. In Logger Pro, the A coefficient is θmax and B is the angular frequency. To find your experimental period from the curve fit, T = 2*π/B. Make a comparison between the theoretical period and the experimental period, using a format that you decide is best and make a conclusion about the appropriateness of the model for your situation. Evaluate the conservation of mechanical energy for one of your data sets (at a minimum) and calculate the energy lost per cycle for one of your data sets (at a minimum). Remember that the ωmax (in the maximum kinetic energy term) is equal to A*B, not just B! Make sure to include experimental uncertainty in your period and energy calculations and energy lost per cycle.
Download the elliptical table to your desktop
Open the file and copy and paste the two columns into a new window of Logger Pro. Once you paste the columns into Logger Pro, you can use the Interpolate function under the Analyze button to determine the values of the elliptical function for any angle used in your experiment.
The description for Newton's Second Law:
For this experiment, the purpose is to evaluate the model for the acceleration of a system presented for your particular experiment. Remember to do all of the curve fits in Logger Pro. Use only the position vs. time graphs, not the velocity vs. time graphs for your calculations (the analysis of the velocity vs. time graphs is optional). Include, at a minimum, four graphs: the one graph showing the levelness of the track with parabola fits on each side (place this graph in the Analysis Section), one sample data graph with NO curve fits on it (in the Procedure Section), one sample graph showing at least one curve fit (showing the fitted parabola and the equation parameters) and, finally, the plot of acceleration vs. the mass ratio with a line fit and error bars on the data points. In order to make the error bars, you will need to propagate the uncertainty in the mass ratio - make sure that you calculate it or you will get a low lab report grade! Remember to make a comment about whether the model is appropriate for your experimental situation or not. You are NOT investigating Newton's Second Law, just a model for the acceleration of the system you are working with. In the analysis section, be sure that you list explicitly the values you obtained from each data file. You do not need to show how you got each one, but you must list all of the values that you used. If you find that the model is not a good one, list some factors that you think may have contributed to the situation in the conclusion section of your report.
Download a copy of the Error Analysis Worksheet
The last labs, entitled "Conservation of Linear Momentum", will be performed during 9th and 10th week.
Lab Report Format
A complete lab report must have the following sections:
Do not forget to update your Table of Contents and to number the pages in your lab notebook!
The first page of your report must have a title, the name of the P.I. (explicitly indicate who was the P.I.), the name of the lab assistant, and the date that the report was turned in (not the date that you performed the experiment!).
*Abstract - a BRIEF description of what you were investigating, how you conducted the experiment and your conclusions based on your experience. The abstract should not be a discussion of what you are going to do in the lab. The abstract cannot be written before you have analyzed your data. In the lab notebook, skip a page or two so that you can write this in at the beginning of the report after you have analyzed your data.
Introduction - a discussion about any details that you think would help someone perform the experiment. This should include a discussion about the model (equations that you are using) or the method selected for performing the tests. If you use models (equations) in your analysis, list the models in this section and describe what each of the variables represent.
**Procedure - a detailed description of what you did in the lab. At the beginning of this section, place the date and the time that you began the experiment. This section must include a schematic, detailing how things were connected, where appropriate. The raw data must appear in this section immediately following the description about how the data was taken. A person must be able to read your procedure section and be able to duplicate your results without having the lab manual present. Do not do any calculations in this section, just record how you performed the experiments and record the raw data. If the data is taken by computer, you must specify the path and filename where the data is stored. This information must be listed in this section right after the description of how the data was taken. Do not simply list all of the files generated at the end of the section.
This section be signed by the instructor before you leave the lab. If you turn in a report without the signature, it will not be accepted!
Analysis - a sample of the calculations made in the lab. This section should include a sample of the error calculations and propagation of errors used in your analysis. The final data that you are analyzing to generate conclusions, the values with appropriate uncertainties, must be shown in this section. The actual calculations for each one does not have to be included, as long as you show an example for one, but you may include them all if you wish. The calculations may be done by the computer, but include printouts of the worksheet in your lab book. Any graphs or printouts that are placed in your notebook must occupy one whole page and be trimmed to fit within the page and not hang outside of the notebook.
*Conclusion - this section must have a conclusion that is based on your experiments and analysis. If your conclusions do not following logically from your analysis, your grade will be deducted significantly. This section must also contain a brief description of significant factors that you think affected your data, in particular, the uncertainties in your data (factors that contributed to the error in your experiment). A good thing to keep in mind is to think of this report as a report you are submitting as part of your job responsibilities. If you do not think your boss would accept what you have to say, it is a safe bet that I will not like it either.
The asterisks indicate the sections that I will pay closest attention to.
Modified October 27, 2014 by Galen C. Duree Jr.