The materials and methods section is not merely a list of what was used and the steps of the procedure. Instead, the section should be written in narrative form in the past tense. This section relates how the research was done and the specifics behind examining the hypotheses. The description of the experiments should provide ample details, including special equipment, procedures, and organisms, such that an independent researcher could repeat the experiments. Experimental details regarding the way measurements were made and data was collected should be included in this section. If different treatments or levels of treatment were a part of the research, they should be fully explained. If the experiments included field research, a detailed account of the conditions and the study site should be included in the methods.
Any factors that are related to analysis of the data, such as the number of replicates for each treatment and the type of statistics performed, should be explained. The independent variable (the factor which was altered, for example, light intensity) and the dependent variable (the parameter which was measured, for example, the production of oxygen) should be clearly identified.
Materials or methods that are standard in lab settings need not be addressed in this section (e.g., how to take readings with a thermometer should not be described unless the method was unusual). The specifics of the experiment are critical. For example, if a sample is heated slowly at first and then the temperature is increased, then simply saying “the sample was heated” is insufficient. If any material of a specific size or type is used for the experiment, then those details should be included. In addition, any equipment which is used in an unconventional or novel manner must be described completely.
A sample of the materials and method section from the example paper shown so far may look like this:
Measurement of oxygen production was performed using freshly obtained healthy Elodea canadensis sprigs (10–15 cm long). The bottom 1 cm of each sprig was removed by cutting diagonally with a razor blade. For each replicate, three E. canadensis sprigs were loosely tied to a glass rod and placed in separate 100 mL glass graduated cylinders with the cut ends upward. A total of three replicates are done for each distance from the light source. The sprigs were completely submerged in the cylinders in a freshly prepared pH 6.9 solution of 3% NaHCO3 (sodium bicarbonate). A 500 mL glass beaker of plain water was positioned adjacent to the cylinders to act as a heat absorber. Control cylinders were wrapped with aluminum foil to exclude light. A 200-watt light source was placed the indicated distance (0, 15, 30, and 45 cm) from the heat absorber and the light was turned on. After 15 minutes, the number of oxygen bubbles evolving from the cut ends of the sprigs in each cylinder in a 5-minute period were counted and recorded. The corrected number of oxygen bubbles was calculated by subtracting the number of bubbles formed in the control cylinder from those formed in the experimental cylinder.
Clarity of the water was determined by Secchi disk observations at two sites in the University Lakes system: the dock at University Lake, and the footbridge over Campus Lake. The Secchi disk was lowered straight down into the water until it could no longer be seen or until the disk hit the lake bottom. The disk was then slowly raised until the disk pattern was just visible and the rope was marked with a clip on the edge of the dock or at the water level. The disk was then raised to the water surface and the rope marked again in the same manner. The distance between the two markings was recorded in meters. Readings were done in duplicate.