Purpose and Hypothesis
This section should be a concise summary of the lab (one paragraph with 3-5 sentences).
• State the purpose, the main scientific ideas/concepts you are trying to learn about or prove/observe (in your own words).
• State your hypothesis: focus on the science, NOT the learning objectives. This should be a prediction in the form of a clear, confident statement regarding what you would expect to happen in your experiment.
Pre‐Lab Questions (if shown in lab instructions document)
Most labs have pre‐lab questions associated with them. copy the questions into your report and answer them in complete sentences, explaining your answers. The example questions shown at the end of this document also apply to the pre‐lab questions.
Experiment/Activity #
Experiment
This section should briefly summarize what you did. NOTE: This section is where you want to place your photos for your lab.
• Data: Clearly present your data. Include data tables and graphs (if any were needed). While graphs may not be needed for every lab, data tables usually are. If you list numbers, make sure units are either with all the numbers or make sure the column label includes the appropriate unit associated with all the numbers in that column.
• Observations: Write in past tense. Here you summarize any observations (visual, sound, sight, or smell) that you think are significant and could help you explain or support your results. The lab may or may not specifically direct you to make observations, however in either case you should include a few general observations from the experiment which are not directly reported in your data tables.
• Do not copy the procedure from the lab manual or list the equipment and chemicals that were used.
Example Table
Step Substance Reagent Result Description
Calculations
This section needs to show calculations for any calculations that were needed in the lab.
• You must show work for the calculations in the questions or you will not get credit for you answer.
Conclusion
This section should summarize in detail the main findings of the lab. Your conclusion should be one paragraph and on the order of 6-10 sentences. Summarize the main results and conclusions from the experiment and the main sources of error. You may also include what you learned in the experiment or any results that you found surprising. For example:
• State how the results compared to expectations and why they did or did not match.
o If the lab is qualitative (observations only), how did the results compare to logical scientific expectations? It is NOT sufficient to say “the results of this lab were what I expected”. You need to say what you expected scientifically and why. Then say why your results matched or did not. If you do not know the value or expectations, look them up and then reference them as you discuss how your results compare.
• State ways to minimize error if the experiment could be repeated. This information needs to be in the conclusion section. You need specific examples for this. It is NOT ok to say “The error could be improved by having better equipment.” Be specific.
• State at least three sources of error in the lab.
o Sources of error do NOT include errors in calculations. Do not say “human error”.
o Error is classified as random or systematic, with explanations.
o Find things within the lab that you could not control this time, but that you might be able to control if you could repeat the experiment under different conditions or with better equipment. Do not list things like not reading the directions, not cleaning glassware, or just being careless.
For this section it is helpful to think of the assumptions that were made in the lab and how your data would be affected if those assumptions were not completely true.
Answer to Questions
Depending on the lab, there might be both Pre and Post lab questions along with Activity questions, which will all be found in the Lab Questions document. All of these questions must be answered for full credit on the lab report.
Be sure to completely answer and explain all the questions and include complete calculations for any questions that require calculations. Please feel free to ask questions in our discussion forums as you work through them.
Examples:
1. Which of the group I chlorides has the lowest molar solubility? What is its solubility in moles/L?
Answer this fully and give your reasoning/explanation for your answer
2. Could you foresee difficulty in quantitative analysis of your unknown ion in aqueous solution or ions by weighing the precipitate? Explain why or why not in quantitative terms.
Answer this fully and give your reasoning/explanation for your answer
References
You need to include, at minimum, one reference. Be sure to reference all information that you use to write you report, including any web resources or your text book. All sources should be cited using APA guidelines.
Students are required to include citations for a couple of reasons. First, include references for the lab manual because the class is following procedures and using materials from the lab vendor. If a person reads a lab, but isn’t already familiar with the procedure, they will have a difficult time understanding what was done. Including a reference at the end of the document provides a pathway for someone to look up the original procedures to help them understand the results. Another point in including references is to practice writing proper citations according to APA guidelines http://ccconline.libguides.com/APAtoolkit. See the report rubric for more information.
