Guidelines for Formal Lab Reports
Remember, a lab report is a way of recording the steps a scientist follows as they work their way through the scientific method. So, each part of a lab report correlates to a specific part of the process as shown below:
Lab Report / Experimental ProcessIntroduction / What is the problem?
Materials and Methods / How did I test the problem?
Results / What happened when I tested the problem?
Discussion / Why did this happen & what does it mean?
Conclusion / How can I apply this?
General Format guidelines: Remember, one of the most important factors people consider when determining to consider your results as reliable is the credibility of the author. The way you choose to present your results helps to establish that credibility. Think of it this way:
Person A: lab report is cobbled together on random sheets of crinkled paper using barely readable handwriting in various colors of ink/pencil. Graphs are sloppy & incomplete. Data tables are sloppy, missing data, have lots of scribbles, etc. Information presented in the test of the report contains many misspellings & uses incorrect grammar. Many words used do not make sense in context or are incorrect homonyms. Sections may or may not be in correct order, but are not clearly labeled and paper is difficult to follow.
Person B: Lab report is neatly printed on computer paper using a color laser printer so the colored details on the graphs & diagrams are visible & placed in a labeled report cover. All graphs, data tables & calculations have been copied/pasted directly into the presentation so they are also neatly computer generated. Data tables are logically organized and referenced in order in the procedure so that information is easy to find. Information presented in the text is free of misspellings/homonym inconsistencies & the content flows and is easy to follow from one section to the other. Content is grammatically correct and makes sense.
In this situation, which person are you likely to believe conducted a careful experiment and drew logical, well thought out conclusions from their data? In other words, if this was a job interview for the doctor whose experiment could either save your life or kill you, who do you hire!?! Below are general guidelines to help you present your ideas as credible:
- Use blue or black Ink or computer (PREFFERED – don’t forget to save it multiple times while writing it!).
- Write only on one side of the paper and double space all writing. This makes it easier to read & leaves
room for the reader to make comments on your report.
- Keep margins straight and consistent.
- Underline each section title. Make section titles very obvious.
- Check spelling, grammar and punctuation - not just with spell check, but also read it to yourself to make
sure it makes sense & that you haven’t used the wrong words (two/too), or better yet have someone else
read it that doesn’t know what you were trying to say (often times you will think it makes sense b/c you’ll
know what you meant & only another person will be able to see it doesn’t make sense.)
- Use thick lines & dark black ink to draw in all diagrams (like a felt tip pen). If you aren’t the greatest artist,
draw it in pencil first & trace over it to avoid mistakes that make it look sloppy.
- Use a ruler for all charts and graphs if hand drawn or produce them on the computer (PREFFERED).
- MOST IMPORTANTLY – make sure the information in each section is what is supposed to be there
according to the descriptions given below, and that it is complete. A typical formal lab report will range
from 8-30 pages (average is about 12) and will feel like you’ve included WAY to much information
compared to the papers you are probably used to writing.
The Parts of a Lab Report
The Introduction (Parts I-V):
Begin with broad statements, including enough background information (with reference to outside sources) to set the stage for your experiment. Then narrow down to your particular study, explaining why it is of interest. Specify the objectives of the experiment (problem statement), and make your hypotheses clear. Include the following in your introduction:
Title/Credits: Put your title at the top of the lab report in large bold print, centered & underlined. Place your name(s) on the next line in smaller bold print, centered with NO underlining. Your title should tell anyone interested in your lab exactly what is being tested & should reflect the variables in your experiment. In other words, if your results were to be published and someone was looking for research about the topic you experimented on, would your title be clear enough to make them call up your research & look at your conclusions?
Background Information: This can be a few statements or a few paragraphs, depending on the complexity and generally known relative knowledge about the concept about which you are experimenting. This section should give the reader enough background information about the concepts you are investigating to give them a general understanding of them as they run and analyze the results of the experiment. It gives them a frame of reference to view the results from so they can understand what is happening.
Problem Statement:This is a statement that clarifies the question you are investigating. It should be written in such a way that it cannot be answered by a yes/no response, and should include both the independent and dependent variables you will be investigating.
Hypothesis: This is a statement that predicts the outcome of your experiment based on the background knowledge you have of whatever it is that you are investigating (this background should be included in the introduction). This statement must include both the independent and dependent variables in the experiment & must be testable. You may use IF …., THEN …. Format to write your hypothesis if you wish. The I.V. will be in the IF statement and the D.V. will be in the THEN statement.
Variables: Identify the variables associated with the lab.
1. Independent Variable (I.V.) – The variable being altered, changed, manipulated.
2. Dependent Variable (D.V.) – The variable being measured, the results.
3. Constants/Controlled variables – list the variables that are to be held constant in all
set-ups of the experiment. Be sure to list all the most directly important to keep constant. In other
words, what variables could have an effect on your results if not kept constant? Then, give a brief
description about how you will keep each of these controlled throughout the experiment.
Experimental Control: Be sure to describe the control set-up that you will be using as a standard of
comparison, and explain how it functions as a control.
Methods (Parts VI-VII):
Use this section to describe exactly how you are testing your hypothesis. This section should be a small part of the report, so don't expand endlessly. Do not include results here.
Materials: This part only needs to be included if you are describing a self designed experiment. It is not necessary if you are conducting a lab that has been written up previously, such as those in our lab book. The
exception to this rule is if you change any materials from those given in the lab, you must include those here.
This will be a list of all materials used within a lab. It will include all volumes, masses, distances and quantities (keep in mind to give TOTAL amounts needed for multiple trials, not just the amounts needed for 1 trial). It will be in column format, for example:
- 1 graduated cylinder - 20 g of NaCl (salt)
- 500 ml of water - 2 plastic cups
Procedures: Them most important consideration for writing the procedures (whether writing your own or
following a prewritten lab) is clarity and detail. Don’t assume the reader knows how to run the experiment
and be sure to carefully explain exactly how to do everything necessary to complete your experiment. The
exception to this is when the experimenter needs to complete basic lab protocols (such as weighing out a
substance on an electronic balance), these do not need quite as much detail. The key is that anyone who
reads your report should be able to duplicate the experiment and obtain the same results that you did.
If this is a self designed experiment, you must include step by step directions for accomplishing
the lab. Directions must be repeatable. Include all equipment to be used and all details for performing the
lab. Each step will be numbered and in list form. Directions should be clear enough for someone with little
knowledge of the content or lab procedures to follow. Each step should be no more than a sentence or two.
For most procedures-especially those with multiple set-ups and many trials- a labeled diagram to accompany
the procedure is very helpful in clarifying steps visually for the reader. One or more diagrams should be added
within the procedures to help aid the reader in understanding what you did (not to mention help you stay
organized and avoid errors while running the experiment!).
If you are following a prewritten lab, such as one from out lab book, summarize briefly the entire process that
was followed and the materials that were used, and then refer to the lab directions and to any flow charts you
have included for the details. Do note any differences in the procedures you actually followed from what was
specified in the lab directions.
Results (Parts VIII-XIII):
This will typically be the longest section of the laboratory write-up. What was experienced and observed will be described in great detail. All measurements and numbers will be included. Data must be presented several forms (numerically, visually/graphically & textually in a narrative). This section includes the following:
Qualitative Observations from the experiment: Describe qualitatively what you observed at multiple
points throughout the experiment in each of the trials/set-ups. Use all 5 senses to make these observations,
not just your eyes. Be detailed in your descriptions and put every observation down-even if you think it is not
important. Often times, you may not realize that something was important until later when you are analyzing
the data & begin to notice patterns- if you don’t record everything, those patterns may never be noticed & an
important part of your research would have been missed! You may be surprised how important something is
once you have all your final data & are trying to interpret it! A chart/table works well to help clearly organize
these ideas while collecting the data.
Raw Data Table: This should include all raw data from the experiment (usually numeric measurements) for
each trial of all setups being run at multiple points in time throughout the experiment. Since you should know
what variables you are testing, these should be set up neatly BEFORE you begin your experiment so that all
data can neatly & reliable be recorded. All data should have units & all tables should be properly labeled
using a table number & title (such as -Table 1: Change in egg mass over time) and they should be in sequential
order. Make sure to refer to these labels when specifying where to record each piece of data in the procedure.
Calculations: In order to condense all your data into more manageable information that you can analyze &
interpret, you will need to make various calculations using your raw data. These usually include percent error,
mean/average, median, & range. However, others may be necessary depending on the experiment. ONE
example of each of your calculations should be given in this section using a word equation and simple
calculation for each value shown in the results table.
Results Table: This table will include only data that has been condensed to the most significant data (often
contains averages of multiple trials) that will be used to draw your conclusions while analyzing your data.
Graphs (Figures): These should be constructed from the condensed data tables and should be properly
labeled with a sequential numbering system and a title that describes the relationship they are showing. Unless
otherwise specified, all figures should show data related to the independent variable on the X-axis and data
related to the dependent variable on the Y-axis. All axes should include a label and units appropriate for the
data that was collected. Also, if you have more than one set of data, you should use different colors to
represent the data associated with each set & include a clearly labeled key to accompany the graph. Be sure to
choose the correct type of graph for the data you are showing. Here is a general guideline to follow:
· A bar graph might be appropriate for comparing different trials or different experimental groups. It also may be a good choice if your independent variable is not numerical.
· A time-series plot can be used if your dependent variable is numerical and your independent variable is time.
· An xy-line graph shows the relationship between your dependent and independent variables when both are numerical and the dependent variable is a function of the independent variable.