Lab Report #1 Specifications: Accuracy vs. Precision
Introduction
Objectives: Follow the lab report guidelines and don't forget that this must be in complete sentences in a paragraph. Besides the main objective to solve the given problem, remember that you should add at least 2 other minor objectives that you think this lab has. Hint: One of your minor objectives should have something to do with learning the use of the quadruple-beam balance.
Theory: Possible topics this time include proper use of the quadruple-beam balance since this is the first time it is being used. Other topics include the difference between accuracy and precision as well as possible examples. Explain why both are important in laboratory situations. Also, here may be included a discussion of metric measurements such as the prefixes of measurement and the tools used to make basic measurements. There will be a class discussion on the metric system within a couple of days so use that to help guide this theory section more. Don't forget to talk about the meniscus during your discussion of accuracy. The theory this time should be about 1 ~ page.
Hypotheses: Which measurement do you think will lead to the least accuracy and thus the greatest percent error? Make sure that what you write here is what you thought in class, not what you learned after the lab. You are allowed to be wrong here as long as you thoroughly support your ideas somehow and don't just guess haphazardly. It should of course be a declarative statement, rather than rewriting the questions that was given to you here.
Methods
Materials: Follow the lab guidelines and make sure that you have included all materials that were
used.
Procedure: It may be copied straight from the lab handout. However, remember that if we make ANY changes or specifications during the lab, you must make these same changes in your report. Finally, don't forget that text inside parentheses should not be included as part of the lab report.
Results
2 Tables Total
1 Table should include each of the 3(or 4) groups' measurements for each of the four properties that were measured. Also, in the same table should be included an average of the 3(or 4) groups' measurements. Finally, the accepted values should also be present in this table. This is the same table that I handed out in lab on the lab sheets.
1 other Table should include just your group's measurements again plus the % precision of each measurement and the % error of each measurement. The other groups' data need not be considered or written here. This table can't be completed until the calculations in the next section are completed.
Again, the only text, as stated in the general lab report guidelines, should be a caption explaining what's in the tables. Follow the lab report guidelines for how to do this.
Calculations
There should be 8 total calculations, 4 for % precision and 4 for % error. Calculations are to be completed only for your individual groups' results, not for the other groups' results. The following equations are to be used:
% Precision = [(Given Measurement-Avg. Measurement) / Avg. Measurement]*100
% Error = (Accepted Value - Experimental Value) x 100
Accepted Value
Calculations must be done using the problem solving method reviewed in class. It is also modeled in the general lab report guidelines so please read the guidelines for important details about how to do calculations. Remember that they can be hand-written, but must be in pencil on loose leaf and follow the other guidelines set in the general guidelines.
Discussion
Once again, I will give you some hints about what to write about, but you will soon be on your own to figure this out. Make INFERENCES about the results in your data tables, especially table #2. Talk about how your results can be used to explain the difference between precision and accuracy. Comment on your degree of accuracy and precision. Generally anything under 10% error and greater than 90% precise are considered good. If you have poor results, comment on why you think that is! In doing so, talk about any possible sources or error and ways to avoid these errors or improve the lab in general. Was your hypothesis correct? Why do you think it was or wasn't?
Don't forget that this section, in addition, to including your inferences, must also include a general statement (s) about whether the objectives were accomplished and how. Finally, the most creative part of the lab is often the end of your discussion where you must think creatively to determine how the procedures of the lab and/or the information learned in the lab and/or the theory proven in the lab can be used in the real world. For this lab, once again, I will actually give you a huge hint so that you get the idea: You learned about precision and accuracy in this lab; name a real life situation where precision is very important and also a real life situation where accuracy is very important. They should not really be the same situation since I want you to highlight the difference between these two words.
This section should include about a 2 page discussion and remember that it should read well and be organized well just like a mini-essay.
References
You probably won't have any for this lab, but if you do, use the links on my website for how to properly reference.
General Reminders (Common mistakes)
· Don't use any personal pronouns!!!!!!! Scientific writing often uses passive voice!
· Follow all formatting guidelines explicitly as outlined on the general lab report guidelines. · You have calculations this time. Students often don’t follow the problem solving method presented in class and unnecessarily lose credit.
· Always write in complete sentences and strive for organization like one would use in essay writing.
· Remember to use the appropriate tense in the appropriate sections. No past tense in
introductions! !!! Refer to guidelines for other details about verb tense.
· Don't forget to double space everything except the procedure, which is single spaced.
· Computer and printer malfunctions are not acceptable so again, start early!
· Email me with any questions!