**Benefits of Metric-only Measurement Instruction in Education:**

**Reason 2: Reclaimed Class Time**

#### A. Metric-only STEM instruction would eliminate the need to teach duplicate concepts and conversions between unrelated measurement units.

The current practice at most K-12 schools is to educate students to understand all important mathematical concepts in two measurement systems: customary units as well as the metric system. This practice adsorbs one of an Educator’s most valuable resource- time in classroom with their students. Currently, when teaching measurement concepts, students are required to first understand the learning objective in customary units, then re-learn the same objective in metric units, and, lastly, the students is expected to perform functions which allow conversions between the two related units of measurement. This practice is the most common method of teaching a child measurement related mathematical concepts in the U.S. Team Metric has labeled it, dual-measurement instruction.

To better illustrate this practice we sometimes use the example of teaching a child to build a house; we like this analogy because measurement is to science as a strong foundation is to well-built home.

In the classroom, if we wanted to teach a student to build a house, the Educator would first teach them to build a sand (customary units) foundation, then the Educator would require the student to build another foundation of concrete (metric units), and finally would expect a student to understand how to turn sand into concrete (converting customary units to metric units).

*Note: Your child just spent 2-4 days learning how to build a foundation to only one very specific type of home.* This knowledge, usually, will not transfer to the next concept.

All the while, within the same 2-4 days, the student’s international counterparts have (1) laid the single, stronger, concrete foundation, (2) put up the walls, and are now (3) working on the roof. Meanwhile, the American students are still struggling to understand the difference between sand and concrete foundations and perform the calculations required to turn sand into the more solid concrete. The American educational system utilizes this teaching methodology in all the important STEM concepts.

Even under the best circumstances with the best Educators, the practice of dual-measurement instruction creates a noticeable knowledge gap between US students and their international counterparts and this knowledge gap compounds every year. It is important to note that most American students never learn to construct the walls, or design roof structures. The limited time allowed for that particular concept was absorbed teaching and trying to understand two unrelated measurement systems and the conversions between them. Within the same amount of time, the international student now has a better and deeper understanding of the concept and a much stronger foundation upon which to build knowledge.

#### B. Metric-only STEM instruction would allow Educators to reclaim the copious amount of instruction time spent on teaching definitions of, and the forced relationships between, customary units.

*Customary units are NOT a system of measurement!* A system is a set of interconnecting parts forming a complex whole. Customary units are an assortment of disparate, unconnected units based on historical artifacts and colonial legacies chiefly supported through our continued teaching of them and reinforced by our consumption habits.

**Customary units do not even have primary definitions. **They are legally defined as fractions of metric standards. When one researches the science of measurement, the fact that customary units do not have primary standards is very significant, and a clear indication that no organization, including the U.S. government, is supporting customary units.

In the classroom, this hodgepodge of units translates into copious amounts of instruction time. There are no consistent relationships in customary units; for instance, there are 12 inches in a foot, three feet in a yard, and 5280 feet in an mile. Therefore, no knowledge is transferable. The student must rely on rote memory and mathematical functions to utilize customary units. A child could spend a month mastering the measure for length but that will not facilitate learning in any other measure such as weight. Students must start from the very beginning with each new measure, **none** of the previous definitions or calculations are transferable. Most students find themselves focusing on the convoluted process needed to solve a problem without ever understanding the concept in which the problem was intended to teach.

In contrast to customary units, the metric system is indeed a true system. The units (centimeter, milligram) have simple and consistent meanings. The conversions are always by 10. The same six prefixes are used throughout the system to simplify the vocabulary. For each characteristic to be measured (except mass), only one unit is defined. That unit can then easily be scaled from very small to the very large by using one of the same six prefixes. The system allows unit conversions within all measures by merely moving the decimal point the correct number of places in either direction. In the classroom, once a student masters the units within one measure, such as length, they immediately understand the unit relationships throughout the entire metric system. All knowledge gained is transferable! All units of the metric system (except mass) have primary definitions based on scientific constants.

For more than 200 years, the metric system has been actively advanced by incorporating scientific discoveries into its definitions. The metric system’s primary purpose is to facilitate easy mathematical and scientific calculations. The metric system allows a student to focus on the problem, not the process; thereby, freeing their brains for higher-order thinking.

See the Compare Units page for graphs

Finally, under a single measurement metric model, we no longer teach unit conversions! All that class time is reclaimed by Educators as well.

#### C. Metric-only STEM instruction would allow teachers to reclaim class time when performing in-class exercises.

Customary units are inherently more difficult to work with as they require complex multiplication and division more frequently than metric units, which are based on units of 10. When working with metric units, students’ computations were found to be 44.9% faster and less error-prone (1985 Tew).