Problem Solving Strategy: Dimensional Analysis

Back in Module 1.1 we asked you to solve a problem involving tuna using dimensional analysis. We?re going to spend a little more time on this problem-solving strategy.

Dimensional analysis is a method used to convert from one unit of measure to another. It is also referred to as "unit analysis," or the "factor-label method," and is used extensively in science.

In a dimensional analysis problem, we place measurements into fraction form, build a product of fractions, and cancel units. The steps for performing a unit analysis are as follows:

1. Write the ending fact with the units called for in the answer.
2. Write the starting fact with units included as a fraction.
3. Determine what conversion facts are needed to get from the starting fact to the desired answer.
4. Between the starting and ending, build a product of fractions using the necessary conversion facts. Arrange the fractions so that the units to be eliminated can be cancelled.
5. Cancel unwanted units.
6. Perform the numerical calculations.

Let's look at the following examples. Note how the canceling is done.