Writing the Materials and Methods Section
The materials and methods section provides details related to the experimental requirements and procedures. This section appears just after the introduction section in a lab report and before the results section. From equipment used during the experiment to measures taken to ensure lab safety, the materials and methods section is an important part of a lab report.
The materials section simply states the processes followed during the experiment and doesn’t involve any analysis or additional details, which are usually reserved for the discussion section of a lab report. Below is the excerpt of the materials and methods section from a diffusion and osmosis lab report.
Materials and Methods Section Example
Materials:
The materials used for the procedure were a petri dish with three holes, gelatin, three dye solutions, potassium dichromate, malachite green, and gentian violet. The three dyes had different molecular weights of 294 MW, 364 MW, and 484 MW.
Methods:
The diameters of the holes were recorded. Then, two to three drops of each dye were placed into separate holes in the gelatin, making sure they were not being overfilled. When the dye was placed in the holes, the dishes were not moved and the dye particles were monitored every fifteen minutes and the distance the dye had moved was recorded in millimeters.
The same process was continued for a total of ninety minutes. Each distance was subtracted from the original size of the hole (5 mm) to determine the difference. Then, the rate of diffusion was calculated by dividing the distance difference at ninety minutes by ninety minutes.
Elements of the Materials and Methods Section
The step-by-step processes followed while conducting an experiment and all the essentials required to conduct the experiment together are known as experimental design. An experimental design is divided into two parts known as materials and methods.
In a lab report, however, the materials and methods are presented as one single section, the purpose of which is to shed light on how the experiment was carried out. Besides the procedure followed and the apparatus used, there are a few other elements in this section; they are listed below.
Measurements
It is important to quantify the materials that can be quantified. For instance, if a chemistry experiment uses solutions, solvents, catalysts, or reagents, then it is important to specify the quantity of these substances. Likewise, it is necessary to quantify the mass of an object or the force acting upon an object in the case of a physics experiment.
Inclusion or Exclusion Criteria
In the case of a psychology study, for instance, if someone participates in an experiment, then it is important to state the eligibility criteria based on which the subjects were chosen. Similarly, it is also necessary to state someone’s ineligibility to participate in a study based on the participation parameters.
Statistical Data Presentation
All data, statistical or otherwise, relevant to the experiment should be presented in this section. The data should not be analyzed or interpreted because the lab report has a separate section for analysis and interpretation of the data.
Referencing
When other studies on the same subject are referred to in the materials and methods section, it is crucial to provide proper references and citations. Failing to properly cite the sources is considered plagiarism, which can lead to serious consequences.
Tips to Write a Great Materials and Methods Section
The materials and methods section should be comprehensive yet precise. Below are some tips to help students put together an explicit methods and materials section:
- The information in the materials and methods section should be presented in a logical and chronological order.
- All details related to variables—dependent, independent, and control—should be included.
- Sample size, mass of the objects, or any other aspect that impacts the outcome of the experiment should be specified.
- The entire section should be written in past tense because the lab report is a record of experiments that have already been completed.
- The experimental procedure should be explained in detail in a series of detailed, sequential paragraphs.
- It is important to check the writing style guide to know when to spell out numbers.
If someone wants to replicate the experiment, they should be easily able to follow the steps mentioned in the materials and methods section. It is, therefore, essential to ensure that this section is not only elaborate but also unambiguous.
