Writing a Lab Report


There are five main parts to a lab report:  The title, the aim, the method, the results and the conclusion.  Here is what to include in each one:


  • Start with the heading such as "Natural Science" or "Physical Science"
  • Then put an appropriate title.  "Investigating the Refraction of Light" is an appropriate title while "Science Project" is not. The title should be informative and brief - make sure it is not too general.  


  • The aim of an experiment is the objective.  In other words, it says what can be learned from the experiment.  "To see how light is affected by lenses and plates of glass of various thickness."
  • The aim should be brief - one or two lines.
  • If a hypothesis was formulated before the experiment was done, than it should be written here.  In addition, any good hypothesis should be backed up with an appropriate justification.


  • If a sheet explaining the method was used in class, often it is enough in this section to write "See instruction sheet . . . " and put the title of the sheet used.
  • If it is necessary to write out the method, follow these instructions:  Similar to a recipe in order to make a cake, the method includes all the information necessary to successfully carry out the experiment:
    1. All the materials needed (this is usually in the form of a separate list).
    2. A step-by-step description of what was done during the experiment.  
      • It should be written using language such as "The beaker is placed on the tripod and heated for four minutes".  Do not use first person such as "We took the beaker and ..."
      • Include the times of each operation, what things should be measured, etc.
      • Be precise about units: "the Petri dishes were kept at 37C for 7 days", "16 grams of magnesium oxide werer collected."
    3. A diagram or images to illustrate the apparatus used and how it was set up.  It can be a drawing or a photo.
  • Try to keep the method as brief but precise and clear as possible.  Someone who has never seen the experiment before should be able to take your paper and repeat the experiment without having to ask you "What's this part here?" or "How did you do this?"


  • The results of the experiment are your observations. Observations are what you saw, heard, felt, etc. during the experiment.  In the results we put what happened during the experiment but we do not state any interpretations of the results.
  • The results are sometimes only qualitative, sometimes only quantitative, but often they are both.  Qualitative refers to results which do not have numbers associated with them:  colors, effervescence (fizzing), texture (smooth or rough), etc.  Quantitative refers to results which have numbers:  109 bubbles, 37C, 12.8 cm, 110 Volts, etc. 
  • Often, a diagram shows the results best.  If you have any photos of the results, put them in this section.
  • If many quantitative results were found, they can be shown as a graph or as a table


  • The conclusion is the most challenging part of the lab report because it involves analyzing the experiment and it tries to explain what the experiment proves.  The conclusion includes some or all of the following information:
    1. Interpretations of the results.  In other words, what do the observations mean?  For example, if an indicator turned from blue to red, explain what significance that has.  
    2. If a hypothesis was given in the aim, the conclusion should state whether the hypothesis was confirmed or contradicted by the experiment.  
    3. Sources of error - if unexpected results were obtained, what possible flaws might have existed in the way the experiment was set up?  How could the experiment be improved?
  • The best place to start when writing the conclusion is to go back to the aim.  Read it again and see what the experiment was trying to show.  Did it show that or something totally different?
  • The conclusion may only be one paragraph but usually takes several paragraphs to explain fully.  Remember, the results are what you got, and the conclusion is what you learned. 




A.W. Damon 2011


Last modification: 2011-03-01