LAB REPORTS

The lab should be written in "past-tense".

Correct "We calibrated the oscilloscope after we took data."

Incorrect "We calibrate the oscilloscope after we take data."

Lab Report Outline

Lab Report Content

1. ABSTRACT (3 pts)
   The abstract must be on a separate page by itself. It should be a short paragraph that contains the following:
   1. clear, consise statement of purpose
   2. what the experiment did to study the issue
   3. summary of results

   The abstract should be self-contained. For example, it should not refer to figures or graphs in the report.

2. DISCUSSION OF BACKGROUND (6 pts)
   1. Provide explanation on background physics as found in places such as:
      • lab write-up
      • text books, library books
      • instructor's lecture
      • include references as necessary
   2. Provide discussion on how your experiment explores these ideas and principles and/or tests some theory. Answer the questions; Of what relevance is this specific lab to these general ideas?, How will these ideas be studied and/or tested?

3. PROCEDURE (3 pts)
   This section should be brief
   1. Like the rest of the report, this section must be a narrative (versus a "recipe" or list).
   2. describe the apparatus
      Write this as if the reader has not seen the lab. References to the lab manual are allowed, but, as with all of the report, use your own words.
   3. Discussion of sigificant deviations from the procedures in the lab manual or deviations from procedures given by the instructor, or innovations introduced by the experimenter
      This must include justifications for these changes.

4. RESULTS & ANALYSIS(8 pts)
   This is the mosts important section of the report. Most of your effort should go into writing this section.
   1. discussion of data
      • Verbally present the data found in your tables and figures to the reader. That is, introduce every single table and figure by number. State what the table or figure includes.
      • Relate these data to the goals of the experiment and background ideas being studied. Address such issues as how the data compare to what you expected to see from your understanding of relevant concepts and theories. Reference tables and figure specifically by table and figure numbers.
      • Include a discussion of the sources of uncertainty in your data and results. This discussion must address the uncertainty in your measurements (which are listed in the data tables). Comments about uncertainty in your results must be supported by the data (rather than simply specualtion on such things as friction or "human error".)
   2. address any specific questions from the manual or instructor and enumerate them where appropriate
   3. include equations and calculations where appropriate
      Lengthy calculations are better suited to the data section or an appendix.
   4. Contradicting statements are not acceptable.
      One should read over the report after it is written and look for contradicting statements and resolve them in a new draft.
   5. Any conclusions about the experiment need to address the data.
      1. address the data specifically: "From our measurements of period for different amplitudes, listed in table xxx, (and/or plotted in figure xxx), we conclude..."
      2. state explicitly how you draw your conclusions from the data:
         "That the period depends on the length can be seen in table xxx, where the period varies from xxx to xxx while the length is changed from xxx to xxx..."
         or
         "From figure xxx one can see that the period depends on the length. In the figure one can see the period is smaller for smaller lengths. Furthermore the dependence is non-linear as can be seen by the trend..."
      3. It is acceptable and proper to discuss ideas not addressed by the data as long as their relevance is made clear:
         "One would expect that air friction would have an effect on the period. We suspect that different geometries and mass densities of the pendulum bob will be effected by friction according to..." "We were not able to draw any significant conclusions about friction from our data. As can be seen in table xxx, we used only two different masses, both of which have the same radius. Their masses did not differ enough to measure the predicted differences in the periods (xxx s) given the errors shown in the table."
      4. When comparing two numbers refer to the comparrison as percent difference. Percent error is not acceptable (even though the lab manual uses percent error).

         This is correct:	percent difference
         This is incorrect:	percent error

5. SUMMARY (2 pts)
   Summarize the lab and the most important results as they relate to the stated purpose. Everthing in this paragraph must already have been stated in earlier sections of the report. Add no new information in this section. The summary can be done in a short paragraph.

6. DATA, GRAPHS & TABLES (8 pts)
   1. tables and figures and calculations (all appropriately labeled with the correct units)
      • The first table is Table 1.
      • The first figure is Figure 1.
      • All tables are together, in order, after the text.
      • All figures are together, in order, after the tables.
      • include one example calculation for each type of calculation done
      • tables must have a title (rather than next to all table entries)
      • tables can have units in column headers
      • table should include a column containing the uncertainty of each measurement
      • figures must include title and axes with appropiate scales and axis labels with appropiate units
      • figures must be drawn by hand on graph paper unless otherwise stated
      • figures must have an indication of the uncertainty of each point on the graph. For example, in a position(x-axis) vs. time(y axis) plot suppose the uncertainty in position is 0.2 cm and the uncertainty in time is 0.5 sec. One draws a point at the correct correct coordinates. A horizontal line of length 0.2 cm is then drawn through the point and a vertical line of length 0.5 sec is drawn through the point.
      • Include horizontal and vertical lines on each point on a graph indicating the uncertainty in each axis value. If the the lines are too small to be seen on the scale being used then state this.
      • When calculating the slope do not use data points. Use points that lie on a line drawn through the data points.
      • When writing calculations on graphs be sure to include units.
      • Make your own tables. Do not copy or rip out the tables from the lab book.
   2. Uncertainty Table. All measurements should have a measurement uncertainty listed. The source of the uncertainty must be stated in the following places.
      • Uncertainty table
      • text of report
      • in each data table
      • in each graph
      In your data section include a table listing the measured quantities, their uncertainties and the source or sources of the uncertainties.
      Table of Uncertainties

      measured quantity	description of measured quantity	uncertainty in measurement or measurements	source of uncertainty
      q	position of image using method 1	+/- 0.05 cm	the optical bench is graded to 0.1 cm
      q	postion of image using method 2	+/- 0.1 cm to +/- 0.8 cm	the image appeared focussed on the screen over a range of screen positions. The degree of uncertainty varied over the range indicated and the specific values for each measurement are listed in the data tables.

1. excessive verbiage: In technical writing it is inappropriate to be less than clear, complete and consise. It is difficult to read and obtain information from technical writing, so including flowery language or excessive words can be distracting and misleading.
2. statements made, which are not supported by the data
3. statements made, which use invalid arguments
4. statements made about results, but without reference to the data. For example, statements about trends seen in a plot of the data. The author needs to explicitly explain how the data follows a trend by referencing the plot and supporting data. Do not leave it to the reader to make connections between your statements and your data.
5. contradicting statements - whether they are explicit in the text or deducible from reading the text
6. specific questions assigned by the instructor left unanswered
7. idle speculation on sources of error and uncertainty (i.e., statements about error need to be backed up by data and/or error analysis)
8. reference to tables or figures without using the table and figure numbers
9. tables and figures which are not referred to in the text

1. Significant observations not called for in the manual or by the instructor, but supported by the data and relevant to the goals of the experiment
2. Proposals for a better experiment. These must address issues of significant improvements on the method use and/or equipment. They must include details on how and why the proposal is a significant improvement.