## Potpourri – Things I Learned … Dimensional Analysis (Thursday 11/12/09)

Last weekend I attended a book summit, which was a chance for me to talk to instructors about the future course of my textbook. One of the instructors from Dyersburg State CC shared this idea for teaching dimensional analysis to students. I will share what I learned, as well as my own spin on this that will tie into incorporating study skills in the classroom.

Group (Class) Activity for Learning Dimensional Analysis

Start by bringing a “conversion note card” to class for each student. Each student needs to have a different conversion factor. On one side of the card will be a unitary fraction that can be used when converting units, on the other side will be the reciprocal of this fraction. For example, one student can have 1 ft / 12 in on one side and 12 in / 1 ft on the other. You will need to create enough cards so that you can perform any conversion.

She begins by writing a quantity such as “4 miles” on the left side of the board, and a target such as ____ inches on the right side of the board. Students are then asked to take their cards and form a chain that converts 4 miles into inches. The student with “5280 ft / 1 mi” would get in line first, followed by the student with “12 in / 1 ft”. Students need to think about the proper order, as well as having to decide which side of their card is appropriate.

The problems can get much more complex than the previous example, including conversions between the English and metric systems and conversions of rates (km/hr to cm/sec).

Creating these cards once will allow you to use them in future semesters. You can also use these cards to teach the different conversion factors to your students in class, provided that the cards are large enough.

My Spin on This

As you teach the different conversion factors, have your students create their own personal set of note cards as shown above. Having their own note cards will help students to memorize these conversion factors. Students can use these cards, lining them up as in the above activity, to do their homework. This will be an effective strategy for visual learners. I’d recommend using a couple of in class examples to demonstrate how to use the note cards.

Summary

There are so many good ideas out there – innovative solutions to make learning fun, real, and meaningful to students. You just have to know where to look, and remember to always keep your ears and eyes open. Thanks to Jani for sharing. I can’t wait to incorporate this into my prealgebra classes later this month.

I am a math instructor at College of the Sequoias in Visalia, CA. If there are topics you’d like me to address in future Potpourri articles, send in your requests through the contact page on my web site. Be sure to check out next Thursday’s article.  – George