For each graph, perform a percent difference calculation between the theoretical slope and y-intercept, and the measured values of slope and y-intercept. The circumference and diameter of each object was measured with the same measuring device in case the two instruments were not calibrated the same. If C is proportional to D, we should get a straight line through the origin. Abstract — summarizes in a paragraph or two at most the purpose of the experiment, as well as the key results and significance and major conclusion s you drew from these results. Take time to look back through the book, the packet, and your class notes to find physics and make an effort to apply it to the topic.
Examples: Exemplary for the most part projects areincluded online at ; a quick glance at these pagesis highly recommended prior to the completion of your project. If the percent variation is smaller than the largest percent v:F06 Guidelines 9 uncertainty in the experiment, then the variation of the experimental values can be attributed to measurement error. Some students will occassionally include a colorful graphic on this page. Usually, the introduction is one paragraph that explains the objectives or purpose of the lab. Investigate these to see whether one or more of them might explain your discrepancy. Your goal for this part of the report is to allow anyone reading the report to duplicate your results.
Sometimes an introduction may contain background information, briefly summarize how the experiment was performed, state the findings of the experiment, and list the conclusions of the investigation. Of course, there might be some reasons for some deviation from the accepted value. Consider each sub-experiment and determine the dominant source of uncertainty. Poor data recording skills lead to poor writeups. This is useful so that the experiment can be repeated by someone else. Do not spend enormous amounts of time explaining data that cannot be explained! Discuss other appropriate findings of interest.
Doing otherwise assumes that there is an accepted value that we are 100% certain of seldom the case and second, it can make results that are perfectly fine appear faulty. Each part should be appropriately labeled e. Conclusions First, write down important measured results. If you are asked by your professors to create this report, there are certain elements that must be in place in addition to a detailed explanation of the entire process and helpful formatting suggestions. If your instructor gives you an outline for how to write a lab report, use that. The percent error between these two values is 5. It may be helpful to provide a figure to diagram your experimental setup.
If your results are completely different than established values, then you have probably measured or calculated something incorrectly. University of Southern Maine Chemistry Dept. If your lab handout includes questions to be answered, include those answers here. Sample Calculations: Include a few of your calculations in this section, e. Some instructors require the lab report be included in a , while others will request a separate report. If so, how did these factors influence your results? Here is how you can write a perfect conclusion for a lab report. Final Remarks You should know that the uncertainty or error analysis methods discussed here are not necessarily the methods used by professional scientists.
Therefore you, the lab student, should always refer to your lab instructor with any disputes concerning the guidelines. Also states the research problem and the reason this problem is being investigated. Any additional actual data pages from the experiment including data written on pre-printed handout labs passed out to the class, or copies from your lab notebook can go in the appendix. It will be helpful to you during the actual performing of the experiment and also when you write your lab report. It's vital that your reader be told the difference between directly measured quantities and derived quantities. Percent Difference The percent difference is a comparison between a theoretical estimate and an experimental result. Data Data are what you measure! Object Description Diameter cm Circumfer.
A graph was made of h for the large aluminum sphere as a function of tave 2 , the square of the average drop time. First, do our data fit the model curve s on the graph s? The times for each height were then averaged. The procedure should be so specific and clearly stated that a stranger could repeat the experiment without knowing anything about it. This is to convey that each journal has its specific format, but all formats contain the same information. Another possible explanation is that air resistance, which is ignored in the theory, slowed the ball down as it fell. In these experiments, you will be asked to make predictions about the behavior of a system based on your physical understanding of the system.
Systematic errors cause all values of a data set to deviate from an expected value by a common factor. The line has an intercept -0. Purpose Tell us what your are trying to prove. Additionally you will make conclusions from your data by reviewing the percentage values. Were you consistently above expected values, or below? Use your book — or better yet, a journal in the field you plan to study, to help you identify the best format to use. The uncertainty in the measurements could be due to the paper-wrapping method of measuring the circumference, circles that may not be perfect, and the limited precision of the measuring devices. Suppose after reviewing your data you find that each percent variation value is less than the largest percent uncertainty value.
The answers often provide ideas to write about in your report. The circumference measurement was obtained by tightly wrapping a small piece of paper around the object, marking the circumference on the paper with a pencil, and measuring this distance with the ruler or caliper. But be consistent in that formatting; every reference should appear with the similar arrangement of information. Everyone is expected to read the assigned experiment before coming to lab. Also include who on your team did what during the experiment and for the report as appropriate recording data, organizing the team, performing particular tasks in the experiment, producing graphs, etc. Was your hypothesis supported or contradicted, or were the results not sufficiently precise to allow you to say one way or the other? Do not show each and every calculation. The variation in g for all of the masses is 2.