Guide to Writing a Lab Report PDF

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A Guide to Writing a Lab Report

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Biology 2: Concepts in Genetics Types of scientific literature •

Primary literature: novel work conducted by the authors of the paper

•

Secondary literature: “review paper” – paper written by an expert in the field, covering what’s currently known from many other papers and a variety of authors, possibly including their own work

•

Tertiary literature: paper or article written for a general audience (e.g. newspapers, popular press). Usually, these are not written by an expert in the field, but sometimes experts do write tertiary papers.

The peer-review publication process in science: primary and secondary papers 1. Once a researcher (or group) has written a paper, they send it to a journal of their choosing 2. The editor of that journal finds several (3+) “peer” scientists with the appropriate expertise to review the paper 3. Reviewers write up their responses to the paper (strengths, weaknesses, suggestions for changes, questions they have, etc.) and send them back to the editor 4. The editor looks at all the reviews and reads the paper as well, and makes a decision: a. accept as is (almost never happens) b. accept with revisions c. allow revisions and resubmission d. reject (and do not resubmit)

Questions to discuss with your group •

Why is this an important process?

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Why do scientists insist upon peer-reviewed sources?

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How else would you suggest publications be screened before they’re published?

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How should you decide whether or not a source is reliable?

Using the articles put on your table, discuss answers to the following questions •

What type of source is each article? Primary, secondary, or tertiary?

What aspects of each article made you decide which type it is? Are any of those aspects found in more than one type of source

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How to cite papers in a lab report Citations within the text The way a citation should look in the text depends upon how many authors there are in the paper. Here’s how to do this, based upon the number of authors: If your paper has this many authors…

At the end of the information concerning the paper

Within the sentence

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(Einstein, 1930 )

.. as stated by Einstein (1930), there is no chance…

2

(Tesla and Westinghouse, 1890)

… as stated by Tesla and Westinghouse (1890), there is no chance…

3 or more

(Darwin et al., 1860)

… as stated by Darwin and others (1860), there is no chance…

Cite it one of these two ways in the text

How these papers look in the text Example 1: citations at the end of phrases or sentences Einstein moved to New Jersey in the 1930s as Hitler rose to power in Germany; he always said that Princeton was a really nice place to live (Einstein, 1930). Living at a time of rapid modernization, Einstein was eternally grateful for commercial electricity, and agreed with its developers that alternating current was the best way to deliver electricity across long distances (Tesla and Westinghouse, 1890). While he was making important contributions to theoretical physics, evolutionary biologists were developing the modern synthesis, bringing together the theory of evolution by natural selection (Darwin et al., 1860) with Mendelian genetics.

Example 2: citations embedded within the sentences Princeton was a really nice place to live, according to Einstein (1930), who moved there in the 1930s as Hitler rose to power in Germany. Living at a time of rapid modernization, he was eternally grateful for the contributions of Tesla and Westinghouse (1890) to the development of alternating current as the standard of electricity delivery. While Einstein was making important contributions to theoretical physics, evolutionary biologists were developing the modern synthesis, bringing together the ideas of Darwin, Wallace, and Bates (1860) with Mendelian genetics.

How these papers look in the Literature Cited section Darwin, C., Wallace, A.R., and Bates, H. 1860. You won’t believe what we went through to bring you the theory of evolution by natural selection. Journal of Weary World Travelers 2: 6-12. Einstein, A. 1930. Life as a German-American scientist in Princeton. New Jersey Digest 1: 1-10. Tesla, N. and Westinghouse, G. 1890. On why alternating current is the way to deliver commercial electricity. Electricity Today 5: 100-105.

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Practice your citation format The example below is from the following paper: Manney, G.L., Santee, M.L., Rex, M., Livesey, N.J., Pitts, M.C., Veefkind, P., Nash, E.R., Wohltmann, I., Lehmann, R., Froidevaux, L., Poole, L.R., Schoeberl, M.R., Haffner, D.P., Davies, J., Dorokhov, V., Gernandt, H., Johnson, B., Kivi, R., Kyrö, E., Larsen, N., Levelt, P.F., Makshtas, A., McElroy, C.T., Nakajima, H., Parrondo, M.C., Tarasick, von der Gathen, P., Kaley, A., and Zinoviev, N.S. 2011. Unprecedented Arctic ozone loss in 2011. Nature 478: 469-475

Introduction, start of the first paragraph - fix any mistakes in the citation format: According to Anderson (1989), since the emergence of the Antarctic ‘ozone hole’ in the 1980s and elucidation of the chemical mechanisms (Solomon, 1999 p. 280; Solomon, Garcia, Rowland, and Wuebbles, 1986; Molina et al., 1987; Anderson, 1989) and meteorological conditions (Schoeberl, 1991) involved in its formation, the likelihood of extreme ozone depletion over the Arctic has been debated.

Here’s the Literature Cited section (bibliography) for the papers in the example above: Anderson, J. G., Brune, W. H. and Proffitt, M. H. 1989. Ozone destruction by chlorine radicals within the Antarctic vortex: the spatial and temporal evolution of ClO-O3 anticorrelation based on in situ ER-2 data. J. Geophys. Res. 94: 11465–11479. Farman, J. C., Gardiner, B. G. and Shanklin, J. D. 1985. Large losses of total ozone in Antarctica reveal seasonal ClOx/NOx interaction. Nature 315: 207–210. Molina, L. T. and Molina, M. J. 1987. Production of Cl2O2 from the self-reaction of the ClO radical. J. Phys. Chem. 91: 433–436. Schoeberl, M. R. and Hartmann, D. L. 1991. The dynamics of the stratospheric polar vortex and its relation to springtime ozone depletions. Science 251: 46–52. Solomon, S. 1999. Stratospheric ozone depletion: a review of concepts and history. Rev. Geophys. 37: 275–316. Solomon, S., Garcia, R. R., Rowland, F. S. and Wuebbles, D. J. 1986. On the depletion of Antarctic ozone. Nature 321: 755–758.

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The sequence of writing sections of your report First just a quick comment about how to start writing a lab report. We’re going to go over writing various sections in the order you write them, not the order they’re assembled when the lab report is completed: The order of sections in a finished lab report is not the order to actually write them in! (see Pechenik, Chapter 9)

The order the sections appear in a lab report

The order to actually write the sections

Abstract

Results

Introduction

Methods

Methods

Discussion

Results

Introduction

Discussion

Abstract

Literature Cited

Literature Cited

Acknowledgements

Acknowledgements

How to write the Methods and Results sections of a lab report Using the papers put on your table (or posted on Blackboard): Methods section  What is the overall message that the Methods section needs to convey?  What do you notice about how the authors wrote the text in this section? Is there enough detail that you could repeat their experiment if you wanted to? Have they written out their protocol like a cookbook recipe, or in another format?  Are there citations of peer-reviewed papers in this section? If so, what are the authors using a citation to back up? Results section  What is the overall message that the Results section needs to convey?  Look at the text in this section. What kinds of messages are the authors conveying with this text?  Look at the tables and figures in this section. Write down some notes about what you notice they’ve done to make their tables and figures clear, simple, and easy to follow.  Look at the figure legends and table legends; this is the text that directly accompanies each figure or table, and they are sequentially numbered. What kind of information are the authors conveying in the figure and table legends about the data?  Are there citations of peer-reviewed papers in this section? If so, what are the authors using a citation to back up?

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Tips for writing the Methods and Results Methods 

Give enough detail so that your experiment can be repeated in its entirety by someone who doesn’t know the experiment at all.



Don’t give unnecessary details. Ask yourself: does someone need to know every detail to be able to repeat the experiment?

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Passive or active voices are ok (this varies across fields and journals in biology)

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Don’t write this section like a recipe or list; write it out in full, detailed sentences.

Results 

Show data in clear, simple figures (graphs) and tables. Ideally, these should be able to “stand alone”; a reader should be able to figure out what you did just by looking at the figures and tables, before even reading the paper. So they should be self-contained and self-explanatory (including the legends, as described below).

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Display means and variation (e.g. standard deviations), not raw data. Variability is shown on figures as error bars, not as the means are plotted.

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Every figure and table should have its own legend (text) explaining what data are shown. These legends do not explain the data, nor do they point out patterns in the data. If you’ve done a statistical test, the results go here as well as in the text of this section

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Do not interpret data in this section. Only point out patterns; do not explain them.

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This section always includes text. It is not simply the figures and tables with their legends. The text describes patterns in the data but does not attempt any explanation of the patterns.

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How to write the Discussion section of a lab report A helpful suggestion: please read Pechenik, Chapter 9. Pages 196-203 focus on the Discussion section, but the entire chapter covers writing lab reports. Many other parts of the book could help you with writing your lab report too, such as Chapter 4 (writing about statistical analyses).

Using the papers put on your table (or posted on Blackboard): Answer the following questions about the Discussion section: What is the overall message that the Discussion section needs to convey? What kinds of things did the authors write at the start, in the middle, and at the end of this section? (i.e. how do the message and topics change through this section) Are there citations of peer-reviewed papers in this section? If so, what kinds of statements are the authors using a citation to back up?

  

Generic Outline of a Discussion section Discussion 

The first idea I’ll cover is this o One thing about idea #1 (these will be full sentences in your outline!!!) o Another thing about idea #1 o



The next idea I’ll cover is this o Here’s the first thing I’ll say about idea #2 o Then I’ll say this about idea #2 o



And finally I’ll say this about idea #2

What others have found in their studies o Here’s what other researchers have found that’s relevant to our study o Here’s some more information that others have demonstrated o These things are relevant to our study because of this o



Which leads me to say this about idea #1

Here’s what we think our results mean, in light of what others have found

What it all means o Here’s the major thing that we found in our study o Other people have also found this when they’ve done similar studies o These findings are important, for these reasons o These findings mean more; here’s how they apply to the “big picture”

Tips for writing the Discussion Discussion 

Start by saying whether or not your data supported your hypothesis

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

If you’ve done a statistical test, say whether or not you could reject H0

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Explain why you think you got the results you did, in this section (not in the Results)

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Be sure to keep your comments linked to your data – you need to back up everything you say with data (yours or someone else’s)

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Compare your results to what others have found. Cite appropriate sources in the text (and list the full references properly in the Literature Cited section at the end of the paper).

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If there are obvious “next steps”, here’s where to include those comments

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This section should make it clear why your results and/or question are interesting, and how they fit into the “bigger picture”

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How to write the Introduction section of a lab report *** Please read Pechenik, Chapter 9, for help with writing this section. Pages 195-202 focus on the Introduction section, but the entire chapter covers writing lab reports. Many other parts of the book could help you with writing your lab report too, so use them too! Using the papers put on your table (or posted on Blackboard), and the reading in Pechenik: Answer the following questions about the Introduction section:   

What is the overall message that the Introduction section needs to convey? What kinds of things did the authors write at the start, in the middle, and at the end of this section? (i.e. how do the message and topics change through this section) Are there citations of peer-reviewed papers in this section? If so, what kinds of statements are the authors using a citation to back up?

Work with your group to prepare a document with answers to the questions above, and submit them to Blackboard, as instructed. Generic outline of an Introduction section Introduction 

Here’s what the “big picture” is for our study o Important big picture stuff (these will be full sentences in your outline!!!) o Some more things about the big picture o



Getting a little closer to what you did, but not there yet o What others have studied that is relevant to the specifics of your experiment o Making sure the readers know this key piece of information o o



Here’s some more information my readers will need to know Here’s why these things are important in the “big picture”

Here’s some other information my reader will need to know to “get” what we did o Here’s some more information that others have demonstrated o



And even more to put our study into context and make it relevant

These things are relevant to our study because of this

And finally, our experiment o This is the null and alternate hypotheses we tested o Here is an explanation of our prediction in the alternate hypothesis, based upon all the information I just explained above o And this is what we found in our results... no details, just a quick comment.

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Tips for writing this section Introduction 

Start broad and end narrow in this section. The first parts should be about the “big picture” or context of the study. This is not specific to the study, but to the general ideas you’re testing (e.g. how cell membrane transport works and why it’s important for cells, what happens if it doesn’t work properly, etc.)



Start with some general background information on what is known about the system you have studied. Do not assume your reader knows anything about what you’ve done.

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Cite peer-reviewed sources for any and all background information you provide. Cite the sources properly in the text (see Class 11b). Later when you write the Literature Cited section, include each source you cite in the text as a full, properly formatted citation in the Literature Cited section (bibliography).

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Don’t trust the authors of papers when they tell you what another paper said. Track down every paper you cite, and make sure it says what you think it says.

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Formally state your null and alternate hypothesis at the end of the Introduction section. By this point, you should have given enough information that your reader has no problem understanding why you are making the prediction you have made....