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Suggestion to teachers for a painless way to teach one facet of SI

by Valerie Antoine, USMA Executive Director

We have found that students learn the correct SI metric unit symbols (short forms are symbols, not abbreviations) much more easily if they get involved by pointing out errors on packages to the companies that sell the products in the packages.

For example, a local teacher, as homework in a measurement class, told the students to check supermarket and drugstore shelves to ensure that the correct symbols are being used (g for gram instead of grms, g., G, etc.).

Then a class project was instigated (at the time students found incorrect symbol usage) where each student: (1) went to the library and researched the name of the company's president and the complete address of the company (as packages often give only the company name and city); then (2) wrote a tactful letter to the president of the company, stating that the student noted incorrect use of the metric symbol. The letter stated the correct way to print the symbol and suggested that when the product package is reprinted the correct symbol be used.

Forty students participated in this project and 6 of them received personal letters from the company, thanking them for their suggestion and saying the next printing would give the correct symbol. A few of those six even received complimentary packages of the product (which in that case were snacks). Of course, it probably wouldn't be a good idea to tell the students they may get a response or samples because too many would expect this and might be disappointed.

This exercise provides a painless way of educating students because:

  1. They quickly learn the correct SI metric symbols.
  2. They are involved in research at the stores and in the library.
  3. They get a lesson in letter writing.
  4. They learn that tact is necessary when correcting someone.

Assignment sheets and worksheets are available:

Metric Patrol (on-screen version for easy preview).
Metric Patrol (PDF version for printing copies for the classroom).

Note: Students should be cautioned to submit their suggestion tactfully, perhaps indicating that the firm's advertising personnel who designed the package may not be aware that the meaning of a symbol can be changed greatly when using the wrong designation. For example, 750 mL indicates contents of a bottle which totals less than a quart. But 750 ML means 750 million liters.

If you try this exercise and get any results, please send a report to USMA, so we can write it up for our newsletter's education column.

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Updated: 2014-11-18