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

Teaching Dimensional Analysis - Interactive Map of Units

There are four interactive maps that are used as active learning experiences to enhance student understanding of dimensional analysis . . . . Maps 1 and 2 are shown for demonstration purposes.

  • Map 1: Length, Area, Mass and Volume
  • Map 2: Volume, Mass, Density, Moles, Molar Mass, and Atoms.
  • Map 3: Map 2 is "duplicated" and placed to the right of the original Map 2 - the left side is Substance A and the right side is Substance B. The coefficient ratios from the balanced equation provide a "bridge" between Substance A units and Substance B units.
  • Map 4: Molarity and PV=nRT is added to Map 3.

Many users have converted their first and second CHEM1 labs into Dimensional Analysis labs. The first lab consists of 10 questions that require students to use Map 1 to arrive at the answers . . . the second lab contains another 10 questions and uses Map 2. The use of interactive dimensional analysis maps in lab has several advantages:

  1. Students are not ready for a wet lab.
  2. Students that miss the first lab can easily make it up because it is online. Also, the 2nd lab can be used to check-in to lab desks and work with Map 2 dimensional analysis problems.
  3. Students that have learned the ratio method in high school are forced to learn the factor-label method which will be invaluable to them in university science courses.
  4. The lab setting is a more intimate environment to help students who struggle with dimensional analysis problems. As the proficient students finish and leave the laboratory, more one-on-one help can be directed toward the remaining students.
  5. This is a perfect setting and a perfect time in the semester to help students become proficient with the use of their calculators - especially in entering numbers in scientific notation.

Map 1: Length, Area, Mass and Volume Map

  1. Click on the starting unit.
  2. Find a path between the starting unit and ending unit and click the units starting with the one adjacent to the starting unit.
  3. This sets up the factor-label part of the dimensional analysis problem.
  4. If the problem wanted you to convert 1.23 miles into fm, you would click on the following units in the order listed: mile, foot, inch, cm, m, fm. Notice that the units have been "set up" at the bottom of the map: it starts with mile and ends with fm and all the units cancel out except fm.
  5. In the "live" implementation, the student would click the Next button to open a web page where she would enter the "numerical part" of the conversion factors and the final answer.



Map 2: Volume, Mass, Density, Moles, Molar Mass, and Atoms

Determine if the problem is asking you to report a numeric answer for a "1-unit" problem or a "2-unit" problem (density, g/mL or molar mass, g/mol).

  1. One Unit
    • Click on the starting unit.
    • Find a path between the starting unit and ending unit and click the units starting with the one adjacent to the starting unit. This sets up the factor-label part of the dimensional analysis problem.
    • In the "live" implementation, the student would click the Next button to open a web page where she would enter the "numerical part" of the conversion factors and the final answer.
  2. Two Unit: If it is asking for density or molar mass, click the Two Unit button - this open a factor-label method in the numerator AND denominator at the bottom of the Map.
    • Click on the starting numerator unit.
    • Find a path between the starting numeratorunit and ending numerator unit and click the units starting with the one adjacent to the starting numeratorunit. This sets up the factor-label part of the dimensional analysis problem for the numerator.
    • Click the Denominator button and repeat the previous step for the units in the denominator.
    • In the "live" implementation, the student would click the Next button to open a web page where she would enter the "numerical part" of the conversion factors and the final answer.