It just dawned on me that we tend to assume that Americans are more familiar with customary measurement than with the metric system. But is it even true? I'll wager that Americans DON'T know customary units as well as we all think (even the most common ones), and that they know metric units BETTER than we all think.
Why not devise a test to find out which we know better? A few examples.... Anyone willing to predict what the results would be? Have several jugs of widely varying sizes. Ask questions like "which jug holds 40 fluid ounces?" "Which jug holds 600 ml?" Continue with a variety of sizes and a variety of units. Give a list of different lengths in a variety of units, and ask them to put the list in order from smallest to largest. Try sorting the list in customary units (inches, feet, yards, etc.) Then try with metric units (mm, cm, m, km...) Repeat the above sorting exercise with other types of common measurements, like mass, volume, & area. Can people really compare square feet, square yards, and acres? Gallons and cubic feet? Ounces and pints? Have a few lengths measured out. For each length, ask how long it is in inches, feet, yards, etc. Then ask in cm, m, etc. What's a valid unit for measuring X? For example, heating power of a stove, power of a light bulb, volume of a bottle, temperature, atmospheric pressure, etc. Give them multiple choice, like BTU, BTU/h, foot-pounds, etc. Then ask the same thing with multiple-choice metric units. For a variety of containers, ask them to guess how many tablespoons, fl oz, pints, quarts, gallons, etc. each container will hold. Then ask the same question for ml, cubic cm, l, etc.
