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BIO 121 - General Biology: Writing a Scientific Report

Find resources and information to support General Biology I students.

Writing a Scientific Report



Communicating your results with other members of the scientific community is as essential as being a competent experimenter. The material in this handout contains some general hints on how to write a good scientific report. The essence of a good report is a clear understanding of the aim, results and significance of the experiment that has been translated into a written form.

Scientific reports are generally written in past tense and passive voice. For example rather than writing: "In this experiment we will examine the effects of temperature on oxygen consumption ....."  you should write: "In this experiment the effects of temperature on oxygen consumption were examined ........"

Scientific style is clear and concise.  Use only as many words as needed to clearly state the information.  Avoid repetition. Say as much as you can in as few words as possible. In this class your audience should be another General Biology student. When you read what you have written, if it is too abstract then go back and write it in plain English. However it is very important to use the correct scientific terminology as learned in class as well as provide, and underline, the species names of the organisms studied.  

You should never use direction quotations in a scientific report. A direct quotation is a statement exactly as it was said by another person and placed between quotation marks. For example:  “The mechanism for the action of JCl on muscle growth is unknown.” is a direct quotation.  Instead, you need to paraphrase ideas stated by other authors by writing them in your own words.  In addition to paraphrasing the information you must cite the source of information both parenthetically and also in a References section. This is explained below. Not citing ideas or information provided by another person is plagiarism and grounds for expulsion from this class.



All relevant facts in a scientific report should be supported by citation to scientific sources such as journals or books. The journals, books and other sources of information that you cite are called the references. It is very important to choose appropriate sources of information. Websites may not be allowed as acceptable sources of information.  All sources, including any acceptable online sources, must have an author/editor and a publisher. Ask your instructor if you are not sure if a source of information is acceptable!

In the text of your report, sources are cited parenthetically, at the end of the information, by the surname(s) of the author(s) and the year of publication, all of which should be in parentheses for example: (Casotti 2001). You will also write out the full citation in the References section at the end of the report. For both parenthetical citations and the full citation format use the “Name-Year System of Citation in Biology” as described in your lab manual only.  Examples are given for many different sources of information. Do not use MLA or APA in this class. Remember: not citing ideas or information of another person is plagiarism and grounds for expulsion from this class.

Always use:

  1. your textbook
  2. your lab manual
  3. at least one source from a peer reviewed scientific scholarly journal
  4. the required number of sources as shown on the rubric for that assignment


Never use as sources:

  1. your lecture notes
  2. encyclopedias
  3. Wikipedia or other online encyclopedias
  4. Most, or all, websites (depending on instructor) 



o Title
o Abstract
o Introduction
o Materials and Methods
o Results
o Discussion
o References

All of the above sections (excluding the title of course) are titled as such.


Every report must have a title. The title should be fairly brief and should use keywords that describe what you are studying. Usually the independent variable, dependent variable and organism being studied are included in the title. 

For example a good title might be “The effect of temperature on the rate of respiration in goldfish.”

The abstract is basically a summary of four things: 1. what was done 2. how it was done 3. what were the major results and 4. what is the significance of the results. These four ideas should be formatted into one paragraph and the total length should be no more than 200 words. You may or may not be asked to write an abstract.

This section should proceed from the general to the specific. It begins with general background information and guides the reader to your few final sentences in your last paragraph. First the experimenter should provide all relevant background information that is necessary for the reader to understand the experiment. Thinking of: who, what, where, when and how may be helpful to insure all relevant information is included. The introduction informs the reader of the context in which the work was done, and why it was necessary to do the work, in other words, why the study was important.

After the background information there should be a clear statement of the aim(s) of the experiment: what questions are you trying to answer? This is followed by your hypotheses and predictions. The final paragraph should include a brief statement of what you did including the organism used, what you measured and how you measured it. You should have provided enough information previously so the reader understands why you have chosen the organism to use and the factor(s) to measure. Correct scientific terminology should be used. In addition to the common name of the organism you must provide the species name which should be underlined or italicized. Never state or discuss your results in the Introduction.

All relevant facts in this section should be supported by citation to scientific sources such as journals or books. This was discussed previously in the section titled “Sources of Information & Citing your sources”. Remember that not citing ideas or information provided by another person is plagiarism and grounds for expulsion from this class.

Materials and methods
This section tells the reader exactly what you did in the laboratory to arrive at the results that you obtained. You can organize this section anyway you wish, either by dividing it into smaller sections using subtitles or keeping it in one large section. The rule of thumb is that it should provide enough information so that someone else could come into a lab and repeat your experiment. Anything quantified, such as by size, volume, mass or number should be included. However it should be clear and concise, not repetitive. If the same procedure is carried out multiple times you can refer to the initial explanation and then include a brief explanation of how this trial differs.  

The materials and methods section of a scientific report is written in the past tense and passive voice.  It is not written as a list of instructions but instead states in paragraph format what was done and how it was done. Do not list materials or steps or refer to your lab manual. Basic lab procedures that are common knowledge such as taking temperature using a thermometer, recording data in a table, graphing data or using a balance to determine mass should not be included.  If a computer program is used to collect or analyze data the name of the program should be stated. However every step you performed in using the computer program does not need to be included. Do not include your results or discussion of results in this section.


This section contains all of your experimental observations and manipulations of the data into a format appropriate to summarize your results. It does not, however, discuss the significance of these results; that belongs in the Discussion section.  You will present your data as text first, followed by tables and finally graphs.

Text: In this section the results are stated in paragraph format. Start this section with one to two sentences reminding the reader of the nature of the experiment.  Then state the specific data (the actual numbers with their units of measurement) indicating minimums, maximums, averages and/or trends seen in each organism or condition. Be clear and organized. Refer the reader to the related tables and figures by number. For example: “As seen in Table 2 the maximum rate of respiration in peas was 1.23 ppm CO2/min.”

Tables: Always include tables when you have a large amount of data to present. Tables should include all the data obtained for example all runs if there are multiple runs, averages if determined etc. Tables are much easier to read than a mass of written data/observations. Do not include a table that contains only one or two numbers; this information can be given in the text section of the results or in the title of a table or graph. . Tables are numbered sequentially and have a unique title that describes the type of data in the table. No two tables should have the same number and/or title and tables should be presented in order by number.

Graphs: Graphs are one possible type of a Figure in a paper and are used to help the reader visualize data for purposes of showing trends in the data. They are not intended for the extraction of accurate data; that is the job of tables. They are also a very good way of summarizing data for the reader into a clear, concise format. Figures should be referred to in the text of a sentence as Figure 1 or at the end of a sentence as (Fig. 1). Like tables, figures are numbered sequentially and each figure has a unique title that describes the information shown in the figure. The title often includes the independent & dependent variables and the name of the organism.  Unlabeled figures are of no use in a scientific report. They are presented in order by number.

The axes of figures must be labeled and units given in parentheses after the label. For example: Height (m). If there is more than one line or set of bars on a graph then these should be labeled or a legend provided.  With a line graph always connect the points with straight lines.  The scale of axes must be appropriate for the data and such that minor fluctuations do not show up as major changes as the important data can be lost by the reader.

In general a line graph is best for presenting continuous data (as in change in a variable over tim) whereas a bar graph is best for representing discrete or separate categories of data. Ask your instructor if you are not sure which type of graph to use.

In this class you may be allowed to produce graphs by hand on graph paper although it is preferred that graphs are made using Excel (which calls them “charts”) or another graph-making computer program.

The purpose of this section is to analyze and interpret your results. Hence, the primary emphasis is on your observations and your interpretation of them and only secondarily on what has been shown by other workers or is written in text books. The reader will be looking for a logical, objective and comprehensive analysis of your results, not merely how well or badly your work compares with that of previous investigators.

Begin this section with a very brief summary of your key results and explain how they support or don’t support your hypotheses. These should be related back to your aim (as stated in the Introduction). In subsequent paragraphs you can deal with results in more detail and bring in relevant information from other papers and books (all of which you must cite) to help you give a full description of what has been going on. However do not introduce new information from sources not cited previously. In addition, explain how your results are significant in a broader biological context.

A common source of problems for students is deciding what is results and what is discussion. A result may be "The oxygen consumption of a mouse is 10 mg O2/kg body mass/min". The discussion should compare the results obtained from different mice and why they occurred and how closely these data resemble previous data by other investigators as well as reasons for possible discrepancies. At the end of this section you should briefly analyze any flaws in the experimental procedure and suggest means to correct them as well as new experiments that may better fulfill or further the aims stated in your Introduction.

This section includes the full description (all the information) for all of the sources you refer to in your paper. The journals, books and other sources of information that you cite are called the references. Everything should be provided that will allow the reader to locate that source and read it more fully. Different disciplines use different styles of citation and scientific journals have different styles of referencing as well. In reports you write for this class you must use the format shown on the following pages entitled “Name-Year System of Citation in Biology”. Note that in the References section you must give the last names and initials of all authors (not use “et al” as in parenthetical citations). For a source with multiple author’s their names should be listed in the same order as listed on the source. Your list of sources should be in alphabetical order by last name.   

Finally: Once you have completed all the above you should correct your report for spelling and grammatical errors. In this day and age of spelling and grammar checkers there is no excuse for incorrect spelling or grammar. It is also a good idea to have someone else read your paper to give generalized feedback and to check for errors you may have missed. Good luck!