Online Lab Submission
Students: Instructors: Virtual Labs: Pre-Lab Assignments
Interactive Animations:

Grading Web Reports

Chem21Labs Web Reports are customized displays of "mined" lab data. Student data stored in our databases are collected, collated, manipulated, sorted, displayed, and graded in seconds after a click of a link. The grade and a customized comment are automatically generated from YOUR rubric. Web Reports are used in the following ways:

  • Display Student Lab Data - if students enter their lab data during lab, a TA / Instructor can click on a web report link and quickly see the "progress" of all students in the lab by how much of the lab data has been entered. Students that are "behind" can be helped by the TA / Instructor. In addition, lab data from multiple lab sections can be pulled into the same web report and sorted to determine if students from different sections have shared their lab data. Any column heading in the web report can be clicked to sort (ascending) the entire report by that column . . . . a second click will sort in a descending manner.
  • Automatic Grading of Reported Precision of Lab Data (Decimal Places) - in addition to simply "viewing" the lab data, web reports can be generated that grade the data on the reported precision of the data (3 decimal places for a mass from a mg balance, 2 decimal places for volumes read from a buret, etc.). The report consists of the following columns:
    1. Student Name Column
    2. A 3-Column Sequence
      • Student Data
      • Number of decimal places reported
      • Grade based on decimal places reported
    3. Total Grade Column - sums all the individual grade columns
    4. Instructor-entered Grade Column - although the Chem21Labs program computes the Total Grade, there may be instances where the Instructor wants to change the grade . . . . this column allows for this situation.
    5. Comment Column - the comment is uniquely constructed from information found in the student's row of information . . . . each student will have a comment based on their lab data / results.
  • Automatic Grading of Reported Significant Figures (SigFigs) of Lab Calculations - grading SigFigs is not a trivial task when the numbers on which the calculation depends is entered by students. Instructors may expect that students will enter a mass to 3 decimal places, but it is only an expectation. During the submmission of the lab report, calculation answers are graded based on a tolerance (i.e. ±1 in 3rd SigFig) that is displayed in the side panel. But, to accurately grade students on the reported SigFigs, a web report must be used. The web report lists the data on which the calculation is based, the SigFigs of this data, determines the required number of SigFigs in the answer and compares that number to the reported number of SigFigs in the answer. Specifically, the web report compares the required and reported SigFigs of both the Molar Mass (blue circle) and the Standard Deviation (blue square) . . . . the grade is assigned by applying the Instructor's rubric. A customized comment is generated for each student that references values specific to that student.
  • Automatic Grading of Accuracy and Precision of Lab Results - the error (relative or percent), R2, and standard deviation are easily graded with a Web Report.

    The report below presents information from a titration of Benzoic acid synthesized in an organic lab when phenylmagnesium bromide reacts with dry ice. The absolute difference in the experimental and theoretical molar mass of benzoic acid (8.7) is assigned a grade when the Instructor's rubric is applied.

    The report below presents information from a boiling point determination of a liquid unknown. The web report "extracts" a certain digit from the 4-digit unknown number - in this case it is the 2nd digit, a "3". The "3" is used to "lookup" the unknown in the stockroom key . . . . it is Acetone. The program then "looks up" the boiling point of acetone and compares it to the experimental boiling point. The difference (4.9) is assigned a grade by applying the Instructor's rubric.