Outside of the math and science worlds, U.S. citizens are so accustomed to the American system of measuring units that they may think it is too difficult to learn the metric system. If you are a teacher looking for ways your students can learn the metric system with little trouble, try using the following approaches.
Tell your students to keep their knowledge of the American measurement system--feet, inches, pounds, miles--separate from their understanding of the metric system. They will have a harder time trying to convert between systems than just focusing on one specific system. To help your students get a grasp on the metric system, make sure you have the following in your classroom: a Celsius thermometer, a kilogram scale, a liter water bottle, several meter sticks, and a bike metric odometer and speedometer. (A digital thermometer and scale will show only metric units.)
Weights and Height
To help your students learn and understand metric height, tape a meter stick to the wall and have your students measure their height in centimeters. Beforehand, give students the following reference points so they can compare and understand their own height measurements: 50 cm (an average newborn baby); 177 cm (the average 18-year-old man); 164 cm (the average 18-year-old woman); and 200 cm (the average tall basketball player). You can use the same approach with metric weight. Have your students get on the scale and weigh themselves. Beforehand, give them the following reference points: 2,500 g to 4,000 g (a newborn baby's average weight), 55 kg to 75 kg (an average lightweight adult); 70 kg to 100 kg (an average medium-weight adult); and 140 kg (the average big football player). To help your students comprehend small weights, have them look at the package on a loaf of bread and read the serving size and weight information. Have each student hold a slice or bread in his hand; if the slice weighs 26 g, students will have an idea of what 26 g means upon reference. Rather than looking at ounces on labels, look for grams (g), kilograms (kg), liters (l) and milliliters (ml). To get an idea of what 500 ml or 1 L feels like, look at a regular-sized water bottle. To visualize 2 L, think of a regular-sized bottle of soda. If you have a box of cereal that weighs 500 g, pick it up to get an idea of what that weight feels like.
Millimeters and Temperature
Students can get an idea of millimeter measuring on the computer. If you have computers in your classroom, have students change word-processing and other computer software to use millimeters rather than inches. If they use Microsoft Word, have them select "options" in the tools menu, choose the "general tab" and select "millimeters." Have them work on typing and setting their document margins using the metric system. If your students work on a Windows XP system, have them go to the "start" menu, select "control panel" and then "regional and language options." Once they see the dialog box and the "standards and formats" section, have them choose the "customize" button and change the measurement system to metric. When teaching Celsius temperature, have your students memorize the following: "Thirty's warm, 20's nice, 10's cold, 0's ice." It also will be helpful for students to know water's boiling point (100 degrees) and body temperature (37 degrees).
Set up three stations in your classroom with items that your students will measure in length, mass and volume. Item by item, have students record their size guesses on a two-column worksheet, then measure the item and record the actual size. As students compare their guesstimates with actual measurements, they will feel more comfortable gauging metric sizes and possibly make guesses that are close to the actual sizes.