For All 200 Level Labs

 

Each group must submit a project report for it's lab project. Alternatively, each member of the group may submit his own report. Project reports should be typewritten and grammatically correct. Hand written equations may be included in typewritten reports if it is done neatly. All graphs must conform to the rules and procedures described in sections "Graphing Data" and "Data Reduction." The text of your project reports, excluding your calculation page(s), must be less than 160 lines in a font no smaller than 10 points. Laboratory instructors may choose to read only the first 160 lines and grade it based solely on that portion.

 Generally speaking, each lab report follows an outline typical of published physics research. It should contain the following.

 Cover/Title Page

The first page of your lab report is the title page. An acceptable title page must contain the following information

• Your name and your VIP student number.
• The name(s) and VIP student number(s) of your partner(s).
• Underline the name(s) of the author(s).
• The title and number of the project.
• The course number (either 201, 202, 211, or 212) and the day of the week and time your section meets.
• The date the project is due.
• Include your abstract at the bottom of the title page.

 

Abstract

 The abstract is a short paragraph, located at the bottom of the title page, stating what quantities you measured (e.g., the acceleration of gravity, test of Ohm's law, etc.), how you measured them (e.g., by dropping weights, measuring voltages and currents, etc.), and your results (e.g., the value of g with the uncertainty, the percent difference between observed and calculated resistances, etc.). The abstract should be only a few sentences, but it should nonetheless be clear and self-contained. As an example, a laboratory project that investigates the relationship between the phase of the moon and the length of a board might read as follows:

Abstract

We investigated the relationship between the phase of the moon and the length of a pine board. We measured the length of the board throughout one lunar month. Within uncertainties, our measurements of the length of the board were constant and we observed no correlation between the length of the board and the phase of the moon. We determined, by averaging our measurements, that the length of the board is (12.4 ± 0.6) cm.

 

Introduction/Background

 The Introduction/Background section of your project report gives a context for your project. This section should contain background information, of an historical and theoretical nature, that explains why your measurements are interesting physics.

One hallmark of a technical document is its reliance on previous efforts in the field for which it is written. It takes advantage of references to quickly cover background information and acknowledge the earlier work of others. If you use a well known technique, refer to the developer(s) of the method. The purpose of the introduction is to prepare the reader for your experiment. For our example project, we might write the introduction as follows:

Introduction

The relationship between wooden boards and the phases of the moon has been a subject of much controversy for many years. Most recent experiments in this field have focused on boards made of wood from pine boards¹. Pine boards are chosen for their density and color, both of which are suspected of making a difference.

The technique we used is similar to the techniques used by earlier investigators². We determined the phase of the moon from information published in the local newspaper and correlated it with the measured length of our board. Using the information from the local paper insures that our measurements are public knowledge and guarantees the accuracy of this part of our experiment. One problem that we encountered in earlier investigations was the uncertainties associated with trying to determine the exact phase of the moon by direct observation with the unaided eye. This will not be a problem here.

 

Notice that information from outside references, such as your course text, is identified by a superscript numeral. The superscript numeral indicates from which reference, in the list at the end of your report, the information was obtained. You may also use a number in square brackets, e.g. [1], in lieu of a superscript. The reference clearly indicates to the reader which information is not original and which source you used.

• Write for an informed audience, such as the students in your class who have not performed the experiment.
• Give the reader a context for understanding the experiment.
• Use references to acknowledge the work of others and cover background information.

 

Procedure

State clearly what you did, why you did it, and how you did it. Use diagrams and tables to illustrate the method. Remember a picture is worth a thousand words. The reader should be able to repeat your measurements from the information given in your report.

If you have jargon for devices, procedures, data sets (private labels), or anything else, define it here. For example, if you have data sets you call "set A", "set B," and "set C", define what these mean so that the reader can follow your discussion. It is preferable to omit jargon, but sometimes it is not practical. Before beginning to write this section, take a few moments to think about your experiment. What is the essence of the method? What are the really important things that you must explain so that your results will make sense? Once you've answered these questions, filling in the details is easier.

• Include a clear statement of what you did, why you did it, and how you did it.
• Include a diagram of the apparatus.
• Define any terminology (equipment parts, procedures, etc.) that is non-standard.

 

Results/Analysis/Physics

This section includes a discussion of the theory and its relationship to the experiment. Your discussion of the theory should include the relationship among the variables, what the variables mean, and how this relationship follows from fundamental principles such as Newton's laws, energy conservation, the universal law of gravitation, etc.

This portion of the report also includes a description of the relationship between theoretically interesting quantities and the measured quantities. For example, suppose you measure position as a function of time for a falling object. Explain the connection between the slope of the graph of position versus time² and the acceleration of gravity.

You should not use any idea or equation that is not explained or referenced to another source. Write for an educated audience. Assume that the reader (in this case the laboratory instructor) is well versed with the basic ideas but that your specific application or technique is new. You do not have to include a long derivation (unless you wish to or are specifically asked to) but you should include more than just a statement of the equations into which you put numbers. Rather than derive an equation, explain in words the assumptions and basic principles involved. Discuss the concepts.

Always explain the basis of your project starting from fundamental laws and principles of physics. For example, start with Archimedes' Principle to explain why an object floats; begin with Newton's Laws to describe the motion of a block sliding down an inclined plane.

There are several types of calculations implied in the lab procedures. Whenever you are asked to compare two experimental results, compute the percent difference. When you are asked to compare with an accepted value, compute the percent error. Physics is a quantitative science. Be specific. These quantities are discussed in the section "Precision and Accuracy."

You should always tabulate all of the data. All raw and calculated results must be collected into tables. The tables must have a descriptive title and the rows and columns must have labels. All measured and calculated quantities must have units (if any) indicated. When you measure something several times to get an average, do not simply report the average; include all the data along with the average (and its uncertainty). Even though the average value is what you will use in subsequent calculations, presenting all the data is important for the lab instructor's evaluation of your report.

Always be clear about the units and the uncertainties in any numerical results you report. As described in the section "Graphing Data," we require you to compute the uncertainties only for four data points, two at each extreme of the graph.

Graphs must conform to the guidelines for plotting in the section "Graphing Data" and must incorporate the methods for finding uncertainties in slopes and y-intercepts described in the section "Data Reduction."

 

• Include all data with uncertainties in tabular form.
• Present data and analysis (including uncertainties) in graphical form.
• Computer generated using spreadsheet or other software
• Propagate experimental uncertainties through the equations to get the uncertainty in the final answer.
• Comparison with another measurement means compute the percent difference.
• Comparison with an accepted value means compute the percent error (section IV)
• All final results must have the correct units and uncertainties.
• Use references to acknowledge the sources of accepted values or values measured by others.

 

Calculation page

Include a page in the report that shows explicitly how all calculations are done. This page may be hand written but it must be neat and orderly. It should include at least one example of every type of calculation in the lab. The page should be organized and labeled so that it is clear what is being calculated and to which set of measurements the calculation corresponds. It is neither necessary nor desirable to include all calculations; only a set of examples is required.

 

Conclusions

The conclusion is where data and theory are synthesized, important points of the experiment are summarized, and connections are made between your findings and the world outside the lab. Your conclusions should include such information as what you learned from the experiment, what you conclude about the quantity you measured, and the sources of uncertainty.

Note: If you simply blame the equipment or human error for disagreement between measured and expected results, your assertion will be taken as evidence that you did the experiment sloppily, and the instructor will deduct points from your grade.

Include a discussion of any questions posed in the project description. In addition, your conclusion should always contain the answers to the following questions:

1. How did your data compare to what you expected? Include a percent difference and/or percent error where appropriate and a discussion of what you expected (see section V.). If no "accepted" value exists or is known, present arguments based on your data, experiment summary research and everyday experience that your result is at least reasonable.
2. Give two different places that you see this phenomenon in everyday life. Be explicit about how your laboratory experience relates to the everyday occurrences you list. For example, if friction is the effect you study in lab, don't just simply list "walking". Explain how friction enters into the walking process and what would happen without it.

Although stylistically it is better to answer the questions in the flow of a written narrative, it makes the laboratory instructor's job of grading more difficult. Thus, the answer to each question (the two given above as well as those found at the end of each lab project) should be clearly marked to facilitate the grading of the report.

• State what was learned from the lab and discuss the uncertainties
• Answer all questions posed in the lab project description
• Answer the two universal questions stated above
• Clearly indicate where each question is being answered

 

References

The written report must reference the sources used to generate your experiment preparation summary. Usually this will be the lecture text and possibly one other source. If the material in your text is not helpful, then reference just to the other source is acceptable.

All quotes must be referenced. If you merely follow a derivation in a textbook or the lab notebook, you must acknowledge the source with a reference. Whatever is not referenced is presumed to be your work. Do not plagiarize.

 

Use a consistent scientific style for your references. In scientific writing, the style of references is different from that commonly used in the humanities. In scientific writing, endnotes are numbered in the text as was indicated in the sample introduction, above. These numbers are assigned in the order in which they appear except that a subsequent reference to the same source uses the same footnote number. For example, suppose your first reference is to book A, your second reference is to book B, and your third reference is to book A again. Then in your text, you would insert endnote number 1 for book A for the first reference to this source, endnote number 2 for the reference to book B, and then use endnote number 1 again for the second reference to book A. Gather all your source citations into a list at the end of the report and number them according to the order in which they are cited in the document. This simplifies the reference task significantly. Without the numbers inserted into the text, you simply have a bibliography of useful readings. What is required here is acknowledgement of what information in your report comes from which source. This numbering scheme provides a simple way to do this and is the accepted style in technical writing.

The style of the citations should include enough information to allow the reader to find the information for himself. A good form for references to a book is

1. J. D. Jackson, Classical Electrodynamics, 2nd Edition, pp 5-9, (John Wiley & Sons, New York, 1975).

And for an article in a magazine or journal

2. B. L. Berman, Atomic and Nuclear Data Tables, 15, 319-372 (1975).

In the first example, the title of the book is in italics and is followed by inclusive page numbers and publisher information. In the second example, the journal title is not italicized, the volume number is underlined and is followed by the inclusive page numbers and the year of publication. If you have several references to the book that you wish make, list the page numbers that include all the relevant material so you can use the numbering scheme given above. This is the way scientists avoid the use of ibid and the large number of endnotes found in English and History papers.

The second example illustrates an acceptable form for referencing a journal article. After the author's name and the journal title (not in italics), comes the journal volume number (underlined), the page numbers, and the year of publication (in parentheses). There are several variations on the basic style given above, but all include essentially the same information. You are free to choose a slightly different style such as is found in Kate Turabian's book, the AIP Style Manual, the Physical Review writers guide, or any other scientific style manual with which you are familiar. But you must choose an appropriate style (similar to that given above) and follow it consistently. This style must include enough information for the reader to find the information to which you refer.

• Your report must reference the sources used for your experiment summary
• Use a consistent and accepted scientific style for references
• Use an endnote number system (superscript or in square brackets) for references.