Lab Report Formats
| Writing Physics Lab Reports. This is a concise
discussion of what is expected in a lab reports for Chabot's
Physics courses. It follows closely protocols laid out here: http://www.physics.upenn.edu/~uglabs/
, page 5 of the Lab Manual (All Courses.) You will generally receive additional information in class.
and review rules on sig. figs with respect to multiplication , division, addition and subtraction, which are important for the lab
write ups. The lab report, other than data and graphs, should only be a few pages. Note the lab handout , including the data sheet, will generally contain all the elements arranged in the following format; so it's largely a question of re-arranging the information into the following categories:
(A) COVER SHEET
Must include: name of experiment and date performed; group partners, individual names and roles; Instructor's name; course and lab section numbers.
#Brief statement (1 paragraph) describing the goals of the lab and methods/procedure used .Do not merely duplicate the laboratory handout description.
#Written in a way that a person not familiar with the lab can quickly understand what the goals and methods used are.
Here is an example of a sentence from an abstract "Using the electronic picket fence method, we found the acceleration of gravity to be 9.9 m/s2 + or - 0.9 m/s2. " Here the goal, or purpose, is clearly to measure the acceleration of gravity. One could explain briefly the picket fence method. The absolute uncertainty of 0.9 m/s2 (discussed below) is quoted.
The statement may be written in terms of a hypothesis. For example, "The purpose of this experiment is to test the hypothesis that this resistor obeys Ohm's Law. The results display a linear relationship between the current and the voltage, Thus, the hypothesis is true."
(C) DATA : A carbonless copy of all handwritten data must be submitted .Show units and uncertainties. Should be well organized and arranged in tables for clarity. Sample printouts of computer generated graphs or tables are appropriate. Show for example uncertainties in the data points and the uncertainty in the slope of the best fit line.
If your lab hand out includes a data sheet and graph paper, include data points and plots here.
(D) ANALYSIS : Outline major calculations and provide an example calculation for each one. Calculate best values and uncertainties (should be done in lab to make sure that the data is correct and sufficient). Include graphs and tables with proper titles and units in sequence or at the end of the report. State the equations used in calculations and define all variables.
For example, suppose you measured the acceleration of gravity 6 times --recorded in your data table--see step (C); and suppose your minimum, average and maximum values were 9.214, 9.7870, and 10.185 m/s2. You can find the uncertainty of the measurement by taking half the difference between the minimum and maximum values. Note there are 5 sig. figs. after I took the average. See class hand out. The uncertainty in this case is (10.185 - 9.214)/2 = 0.971/2 = 0.4855 m/s2. According to the rules set down by the Picket Fence lab hand outs , you express your result as 9.7870 m/s2 + or - 4855 m/s2. If you round the uncertainty to one sig. fig, then the result is reported as 9.8 + or - 0.5.
These values would be recorded in your data table (under DATA) and discussed in the ANALYSIS section.
If your lab hand out includes analysis questions to be answered, include them here.
(E) SUMMARY/ERROR: Following upon the above-mentioned analysis, a short summary (no more than a few paragraphs) considering what could have caused error in your measurement. Include all sources of error (the more insightful the better). Determine the largest source of error and describe how it could be improved. Explain possible sources of systematic error that would effect the experiment's accuracy. Explain possible sources of random error that would effect the experiment's precision.
(F) CONCLUSION Brief (a few paragraphs). Compare your results to accepted values. Discuss what the data shows, why, and what you've learned. If your lab hand out includes a data sheet and tables , include your comparison here. See sample computation hand out. For example, here you would compute the percent error between your average value 9.7870 m/s2 and the accepted value 9.8 m/s2, where percent error =
(9.7870 - 9.8)*100%/9.8 = (0.013)/9.8*100 %. = 0 % . We get 0 % since 0.013 has a zero in the 1/10 place, the maximum precision of the accepted value 9.8 . Does the accepted value (i.e. 9.8 m/s2.) fall within your range based on the uncertainty? You check this way: The maximum value in the range is 9.7870 + 0.4855 = 10.2725. The minimum value is 9.7870 - 0.4855 = 9.3015. We see that 9.3015 < 9.8 < 10.2725. Thus, you would answer yes.