Writing Physics Lab ReportsLabs are the basis for our understanding of the key concepts in physics.
What follows are the basic guidelines for success in writing a quality lab report.General guidelines1.
Your report should be hand-written in a composition book reserved for this purpose only. Write only on the right side of the page (one-sided).
Writing with a pen or pencil is acceptable.2.Your name, the name(s) of all members of your laboratory group and the date the investigation was performed is to be written in the upper right hand corner of the first page of each report.3.
An appropriate title for the report should be placed at the top of the first page of the report.4.Each of the following sections of the laboratory report should be included in order and labeled with the section names as headings. 5.Your report should conform to accepted standards of good writing.
Use complete sentences, proper grammar, punctuation, and spelling. Your writing style should be expositoryPurposeThis is a statement of the phenomena being investigated. It provides the overall direction for the investigation and must be addressed in the conclusion.
It will generally be given to you or discussed in class during the pre-lab discussion. VariablesIdentify the independent, dependent, and any controlled variables for this investigation, including their symbol and unit [i.e.: position, x(m)].
Define any new variables.ApparatusA detailed, labeled diagram listing and illustrating the configuration of the apparatus should be included in this section. See the example at right.
ProcedureThe procedure is a step-by-step description describing the method you used in conducting this investigation.
It should include, at a minimum, what you measured, how you measured it, and how you controlled variables (if it was necessary to do so). Did you use multiple trials?Include information about how you evaluated your data (averages, graphs, etc).
Someone who was not present during the lab should be able to understand how the experiment was performed and be able to replicate it by reading your procedure.
DataAll of the measurements you made should be recorded into a neat table with identifying headings.
Data consists only of those values measured directly from the experimental apparatus. No values obtained by way of mathematical manipulations (i.e.: averages) or interpretations of any kind may be included in this section.
Data should consist of as many trials as judgment would indicate necessary. The units for physical measurements in a data table should be specified in the column heading only.
Evaluation of Data This section should include all graphs, description and analysis of graphs, and post laboratory calculations. State each formula, and if necessary,
identify the symbols used in the formula. If repetitive calculations are to be performed, substitute only one set of data into each formula and then construct a table of values for all additional calculated values.
Be certain that your final calculated values are expressed to the correct number of significant figures. Do not show your arithmetic calculations.Scatter plots should be properly formatted.
This includes a descriptive title for each and proper labels for the axes, including units. Each graph should be accompanied by a verbal description detailing what was graphed, the shape of the best-fitting line, the proportionality (relationship) indicated, and the method you used to verify the relationship.
The slope and intercept of each linear best-fitting line should be clearly stated, including the proper units for each.
The equation for each best-fitting line should also be stated using the proper symbols (as defined in the variables section) and units for slope and intercept.
The 5% rule may be invoked, if appropriate (clearly state if it is).This is not the place for interpretations or meaning-making. You are simply representing your data in verbal, graphical, and algebraic form.ConclusionThis is the section for discussing what you found and what it means.
Your conclusions must be based on and directly address your stated purpose. Cite the evidence you used as the basis for your findings.
This evidence should include but is not necessarily limited to an interpretation of the graphs you produced in the evaluation section.
Refer to them. State the relationship between the experimental variables using a clear, concise, plain-and-ordinary-language sentence.
How did the dependent variable change in response to changes in the independent variable? This should first be stated in very simple terms, i.e.; “As _______ (your independent variable) increased, _________ (your dependent variable) decreased”
What trends do the graphs show? The trends identified through the graphs tell us how changes in the variables relate to each other.
Trends are identified based on the proportional relationship that exists between the variables. For example, each of the three graphs shown below exhibit increasing functions.
The difference is that for regular changes in “x”, the change in “y” is different for each example.
The trend statement gives more detail about how the variables change in relation to each other. For example, you might write that “as x increases so does y, but at a decreasing rate, as shown by its root curve shape.” Follow this with a mathematical statement that includes the proportionality and equations found.
Discuss the significance, meaning, and implications of your graphical and mathematical representations. What do they show? How could they be used?
What is the meaning of the slopes and intercepts of your linear graphs?
What new quantities do they represent and how are they defined?
Do not use jargon or overly technical terms. Finally, a short discussion about the amount of error present in your investigation.
Discuss how well your best-fitting lines fit your data points. These three graphs show different amounts of experimental error. Which graph shows a small amount of error?
Which shows a moderate amount and which shows a large amount?
How confident are you with your findings? Why? What could you change to improve your results if you were to repeat this investigation?