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Writing a Lab Note or Report

Page history last edited by David Young 7 years, 6 months ago

Here are some guidelines


Remember, many assignments will only require you to complete part of a full lab report.  These smaller lab notes follow the same format as a full report but do not contain all of the sections.  Read and listen carefully to the instructions given by your teacher.




The first part of a complete laboratory investigation is to make a plan.  This involves the following steps


UNDERSTAND something about concept(s) related to the investigation you wish to conduct

  • do some background research, this will help you with ideas for the experiment and to write the introduction.  Google is a good place to start.  Remember to bookmark useful websites as you might need to cite them later.  Your introduction could include information on the topic you are studying, the factor you choose to investigate,  etc.


BE VERY SPECIFIC about what you are planning to investigate 

  • Decide on a research (or investigative) question.  Try to be as specific as possible.
  • Your question and will look something like "What is the effect of ______________________ on ___________________" 
  • Identify the independent and dependent variables.  This should be clear from the research question.


Design a FAIR TEST 

  • Decide how you will manipulate the independent variable and how you will measure them both.
  • What variables need to be kept fixed?  How will you ensure a fair test?
  • List the materials you will need to complete the experiment.  Choose the most precise measuring tools available.



  • Write a procedure consisting of numbered steps.  Each step should only contain one command. 
  • Make sure you have at least FIVE (more is better) manipulations of the independent variable and REPEATED (3 or more) trials for each.


Now you have some ideas and a draft.  It is time to write this all down scientifically.  There are lots of places you can get information on how to do this. 



Data Collection, Processing and Analysis



This section contains observations and data collected during the course of the experiment.  Such data is called raw data and includes the measurements you made during the lab (make sure you make all the appropriate measurements and enough of them) and any other observations that were made (what you saw, smelled, or heard are examples of qualitative observations and are important to include)




Qualitative Observations

  • observations that are not measurements are qualitative observations
  • it is appropriate to make notes in this section of factors that may lead to errors, weaknesses or limitations in the experiment or the data.  For example, it would be suitable to note an unstable meter value, or a difficulty making measurements



Quantitative Observations


Raw data must be presented neatly and in a format that is easy to understand.  This will almost always require a table.


Data Tables

  • Use a standard row/column format
  • Draw a box around the table and use lines where appropriate to separate rows/columns of data. 
  • It is common practice to write the independent variable data in a column to the left of the dependent variable data.
  • Table headings must include units of measurement and any applicable uncertainties
  • Titles for tables are very important.  Titles must be meaningful and contain a written description of data presented. 
  • Do not overlap a table on two pages.  Keep all data on one page!



Raw data is processed in the analysis section with the results presented (Note: it is quite common for both raw and processed data to be presented together in the same table).  Data processing includes any calculated values obtained from raw data, averages, graphing raw data, converting sketches to formal diagrams etc.  The two most important considerations when processing data are to a) perform calculations correctly and b) present results in a way that is easy to interpret.


Presenting processed data in tables:

  • it is important to separate raw data from processed data in tables.  If you wish to combine data into one table, ways to indicate columns of processed data include using a double line between raw and processed columns, shading the columns containing calculated values, or changing the font (to italics) for calculated values
  • any data processing should be accompanied by a sample calculation to clearly show how the processed result was obtained.  YOU DO NOT NEED TO SHOW EVERY CALCULATION FOR EACH LINE OF DATA, just one example for each type of calculation


Presenting processed data in graphs:

Don’t forget:  Your graph must be at least half a page in size, be placed at the appropriate place in your report and include

  • a descriptive title
  • labeled axis with units
  • appropriate scale
  • properly plotted points with uncertainty bars
  • line of best fit (linear or curve)
  • the equation of line – if linear (use points on the best fit line to calculate)
  • legend or key (if more than one series of data)


Students often fail to realize the significance of data processing and tend to focus more on drawing nice tables and graphs without realizing and clearly presenting what the data means.  The data is your evidence.  You use this evidence to make a conclusion. Your data analysis and presentation tell the story from the raw data (a bunch of numbers) to the conclusion statement.  Make this story clear.  CHECK OUT THIS EXAMPLE



Conclusion and Evaluation (still working on this section)


This section begins with a statement of results, an explanation and conclusions.  The conclusion should be backed up with relevant information and a statement of validity for the experimental result.  This may mean doing some research in order to compare an experimentally determined value with an accepted value from the literature.  


Make sure your conclusion is valid.  In other words it must reflect the data on paper and NOT what you think is or should be the correct answer.  The data may not be correct, your conclusion should consider that.


The conclusion can be simply broken into three parts:

  1. A knowledge claim that answers the research question
  2. Evidence to support the knowledge claim
  3. Comparing the knowledge claim to others if possible



Evaluation of the lab is one of the more difficult parts.  Students must critically examine the entire lab process including the procedure, the equipment used, how the lab was conducted and how the data was analyzed in an attempt to identify significant limitations, weaknesses or errors.  Furthermore, you are expected to provide realistic suggestions to improve where fault has been identified.


Limitations, weaknesses and errors include

  • poor measuring equipment 
  • difficulty making accurate measurements
  • variables that are difficult to control such as friction, air resistance and heat loss


Human mistakes are not considered to fall in this category.  If you made a mistake during the lab, it is not acceptable to publish incorrect results and then blame it on a mistake you knowingly made.  Care must be taken to ensure this does not occur and may mean you arrange an alternate time to repeat a lab that has been ruined by careless technique.


Use the following guide to help you write this last section:

  1. Identify a fault, weakness or limitation in the lab activity
  2. Discuss how the fault, weakness or limitation is shown in the results (refer to data)
  3. Suggest a realistic improvement 




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