MATERIALS AND METHODS

A well written methods sections provides enough information that the experiment could be repeated by another scientist. It also provides the reader with enough information that they can evaluate the validity of your data based on the experimental design. Using past tense, clearly and concisely describe in your own words the procedures and the essential materials used. Begin by creating an outline that follows a logical pattern. The following are usually included in a methods section:

1. The genus (capitalized and underlined or italicized) and species (underlined or italicized but not capitalized) of the experimental organism and where it was obtained;

2. The basic experimental design indicating the number of replicates for each treatment and which treatment serves as the control;

3. The rationale for the methods used;

4. The concentrations and quantities (or proportions) of reagents used;

5. Defininitions of any new or unusual terms or abbreviations;

6. The conditions of the experiment such as temp, photoperiod, pH;

7. The types of measurements and how they were made;

8. The statistical test used and why;

9. For field studies, a description of the study site and when the study was conducted.

You may refer to your lab handout or scientific papers for specific information, but you must reference them using standard scientific format.

e.g. Chloroplasts were isolated using the techniques described by Ross (1974).

• Omit details that are not essential for repetition of the experiment

e.g. I placed the test tubes in the test tube rack and my partner measured the solutions. e.g. I dropped one tube and we had to start over again.

e.g. Test tubes were held upright in a metal test tube rack.

e.g. I labeled the petri dishes with treatment number and recorded the time.

• Use precise language
  
  

Vague: I measured the length of the stem several times during the experiment.

Precise: I measured the length of the stem three and six days after germination.

• Do not write the procedures as if they were directions in a lab manual.

Incorrect: First, label 5 finger bowls (A-E). Then fill each bowl with 20% Steinberg's solution (pH 7.4). Place three tadpoles in each bowl. The bowls should then be labeled and put into an environmental chamber at 18⁰C or 25⁰C.

Correct: Three tadpoles were maintained in a finger bowl containing 200 ml of 20% Steinberg's solution (pH 7.4) at either 18⁰C or 25⁰C.

• Use past tense to describe what was done rather than telling the reader how to do it.