Write an introduction that explains the question or issue the lab experiment is addressing. Include any relevant history and explain why the experiment is taking the approach that it is. Finish with a brief outline of the methods used in the experiment and the hypothesized results.
Explain in detail how you did the experiment, including the exact tools you used in each step and the methods you used to get to your eventual results. A good "methods and materials" section should have enough detail that anyone in your lab setting can do the same procedure and get the same results you did.
Describe your results using both detailed paragraphs and visual aids, such as graphs or tables. Every graph or table requires a title as well as a number, which makes it easier for you to reference in your results description.
Evaluate the results of the experiment and comment on what the experiment either proves or disproves and what work could be done in the future to further the line of thought the experiment follows. This conclusion also answers any likely questions a reader would have about the procedure or the findings.
Include a list of all your references, which are any sources from which you derived information. Always credit original authors for their work in lab reports so there is no confusion over where certain information came from. List references in alphabetical order by the first letter of each author's last name.