Writing a Lab Report

The key to writing any type of paper is to understand the purpose. In other words, why are you writing it? What are you trying to accomplish? In the lab, our purpose is to explore by experimentation and then to explain our results. Our writing should be precise, technical and definitive. Think of it as a recipe. A main title as well as section titles help organize the report. What follows is a sound format for a laboratory report.


State Title and Define Hypothesis. Remember that the scientist seeks to explore. Summarize your expected outcome or what you think will or should happen based on your prior knowledge. For example: "When we add baking soda to vinegar, we get a fizzing reaction. "Subtituting another weak acid (e.g. coca cola) for acetic acid (vinegar) will have no affect on the fizzing action of baking soda". In addition, an appropiate title should head the report. The reader should be able to understand the key elements of the experiment. For example: "Determination of the Reactivity of Baking Soda Towards Weak Acids"


Materials Listed. Like any good recipe, your report must include the specific materials you used - and in what quantities. This is an area for detail and description. Using a bulleted list works well in this section. Remember that scientists must be able to demonstrate their experiments so it must be repeatable. For this to occur, an accurate listing of all must be present in your report.


Methods Used. Be very specific. Describe in detail what procedures you followed, step by step. It is essential that this be very sequential and orderly. It is also a great place to insert a diagram or flow chart.


Results. Describe the quality of matter: smoke, noise, odors and any other details you may have observed. Remember these sensory details: sight (color, size, quantity), sound (tinny, hissing, sizzling, popping), smell (pungent, acidic, sweet, spicy), touch (sticky, smooth, soft, coarse) and taste (only if applicable). Your observations must be measured and values given using correct units. In this section include data, diagrams, graphs and charts.


Conclusions. Summarize what you had predicted would happen versus what actual did happen. Use this section to support or reject your hypothesis. If necessary, rewrite it to explain your results. Using the coca cola example - suppose the coca cola created a reaction, but it was less dramatic than the experiment with vinegar. You might conclude that you had been right to suppose that other acids produced similar results, but that they were less potent. Therefore, the acid in them was different. You could rewrite your hypothesis to say that other acids -more like vinegar in composition - would get better results.


Remember to keep your lab reports in a notebook and in sequential order. Write neatly and highlight different concepts or vocabulary. Remember the words of Thomas Edison: "Invention is 1% inspiration and 99% perspiration!"


Be sure to view the grading rubric for lab assignments.


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