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Manual Operation of the Spectrophotometer: Performance Checklist

 Evaluating and assessing students' performance during laboratory procedures is difficult if there are no specific and structured checklists to monitor the performance.

The following are pointers on how to prepare a checklist for laboratory procedure evaluations.

1.Before preparing the checklist, be certain to establish your goals and objectives for that particular activity. Each activity should have its own evaluation tool based on the objectives.

i.e. At the end of the activity, the student should be able to:

1. name and identify the basic components of the spectrophotometer;
2. discuss the principle of spectrophotometry;
3. read properly the unknown solution in the spectrophotometer;
4. terminate the procedure with the proper sequence of events

2.After establishing the procedure's objectives, the different steps of the procedure should be identified clearly to determine which would be considered as the criteria.

i.e. identification of the basic components of the spectrophotometer excellent

3.Determine what scale to use in the evaluation. You can utilize the graded scale,

From 1- 5,

1 - done with more than 3 errors - poor
2 - done but with 3 errors - fair
3 done but with 2 errors - good
4 done but with 1 error - very good
5 done with no errors. - excellent

Or you could just use these two parameters.

Satisfactory - step has been performed well
Unsatisfactory - step has not been performed well

4.Each step of the procedure should be assigned one evaluation criteria.

i.e. identification of the light source
identification of the monochromator
identification of the cuvette

Notice that all of the 3 items above refer to only one objective the identification of the parts of the spectrophotometer.

5.The checklist should be used in rating all of the students to obtain objective results in the evaluation.

6.Leave a space for a comment portion in the checklist. This is where the instructor writes the corrections of the student's performance.

7.The criteria maybe modified for other procedures to fit in more complicated steps.

8.The student should be given a feedback by the instructor himself. How can the student improve if he does not know the error that he had committed in the procedure?

9.Be specific about the criteria involved in the procedure's steps. Sometimes the instructions are so vague, that the student has no idea what you would like him to perform and observe.

10.Checklists are good evaluation tools because they are objective. Instructors must remember however, that these are not perfect. The instructor has still the final decision. Modifications should be done regularly to come up with the best checklist for particular procedures.

Having objective tools -like checklists - in evaluating students will help a lot in reducing subjective biases.

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