Writing Lab Reports for BIO 1654

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Introduction

The Introduction is the section in which you describe the background information of your experiment. For example, if you were doing an experiment of the process of diffusion, you would want to include a brief paragraph describing what diffusion is, what are properties of diffusion and why is diffusion important (especially to biologists). Why do you care about diffusion and why should the reader care! The Introduction should contain enough information for the reader (who may not know much about diffusion) to understand diffusion and thus your experiment. This section should take some thinking, and should not be copied from your lab manual or text book (although both would be good sources for information and remember to cite them if they are used).

 

A second purpose of the introduction is to describe the purpose(s) of your experiment (in context to the background information that you have provided). For example, what questions about diffusion were you trying to answer in your experiments. ("We examined the effect of temperature on the rate of diffusion.", for example). The order of these two sections of the Introduction is determined by your writing style.

 

Methods and Materials

This is the section in which you describe the procudures and the materials that you used to to perform the experiment. This should not be a simple list of the procedures you did (as outlined in the lab manual) but should be a narrative (with paragraphs) describing what you did (and the rationale of what you did) during the experiment. When listing any solutions, you must include the concentration of all items in the solution. For example, "We add a salt solution" is not acceptable. A better sentance would be " We added 2.5 ml of 0.1 M NaCl." For instruments used in the experiments, you should include the model and the name of the manufacturer if known ( "The absorbance was measured with a spectrophotometer (Cary 14 model, Beckman Equipment Corp.)" or "The absorbance was measured with a Cary 14 spectrophotometer (Beckman Equipment Corp)).

One of the more common mistakes of students is to make this section too detailed. You may assume that most readers are familiar with with techniques that you use. For example, you can assume that the reader knows how to pipette or to measure the absorbance of a solution. Therefore, these should not be described. You want to provide enough information so that the reader could repeat the experiement but you generally do not need to describe detailed instructions on how to pipette, for example. Thus "We added 100 ml of 0.25 M glucose to the incubation media" is sufficient while " We poured 100 ml of 0.25 M glucose into a graduated cylinder and then poured the contents of the graduated cyllinder into beaker that contained the incubation media" has to much detail - you can assume the reader knows how to add 100 ml.

I liek to imagine that writing the Methods and Materials is similar to writing instructions on how to make a cake for a boxed mix. The instructions on the cake box do not tell you how to use your oven, they assume you already know that. The instructions do not tell you howto use the electric mixer, they assume you know that. The instructions do tell you exactly how to make the cake but do not describe the details of how to perform the specific techniques (hhow t use the oven or the electric mixer). When you write the Methods and Materials, write as if you were writing the instructions for a cake (but don't make a numbered list!).

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